Instrument Procedures 

Handbook

U.S. Department of Transportation

FEDERAL AVIATION ADMINISTRATION

Flight Standards Service

2014
ii
iii

This handbook supersedes FAA-H-8261-1A, Instrument Procedures Handbook, dated 2007. It is designed as a technical 

reference for all pilots who operate under instrument flight rules (IFR) in the National Airspace System (NAS). It expands 

and updates information contained in the FAA-H-8083-15B, Instrument Flying Handbook, and introduces advanced 

information for IFR operations. Instrument flight instructors, instrument pilots, and instrument students will also find this 

handbook a valuable resource since it is used as a reference for the Airline Transport Pilot and Instrument Knowledge Tests 

and for the Practical Test Standards. It also provides detailed coverage of instrument charts and procedures including IFR 

takeoff, departure, en route, arrival, approach, and landing. Safety information covering relevant subjects such as runway 

incursion, land and hold short operations, controlled flight into terrain, and human factors issues also are included.

This handbook conforms to pilot training and certification concepts established by the FAA. The discussion and 

explanations reflect the most commonly used instrument procedures. Occasionally, the word “must” or similar language 

is used where the desired action is deemed critical. The use of such language is not intended to add to, interpret, or 

relieve pilots of their responsibility imposed by Title 14 of the Code of Federal Regulations (14 CFR).

It is essential for persons using this handbook to also become familiar with and apply the pertinent parts of 14 CFR and 

the Aeronautical Information Manual (AIM). The CFR, AIM, this handbook, AC 00-2.15, Advisory Circular Checklist, which 

transmits the current status of FAA advisory circulars, and other FAA technical references are available via the internet at 

the FAA Home Page http://www.faa.gov. Information regarding the purchase of FAA subscription aeronautical navigation 

products, such as charts, Airport/Facility Directory, and other publications can be accessed at http://faacharts.faa.gov.

This handbook is available for download, in PDF format, from the FAA’s Regulations and Policies website at: 

http://www.faa.gov/regulations_policies/handbooks_manuals/aviation/instrument_procedures_handbook/

This handbook is published by the United States Department of Transportation, Federal Aviation Administration, Flight 

Technologies and Procedures Division, Flight Procedures Standards Branch, AFS-420, 6500 S. MacArthur Blvd, Ste 104, 

Oklahoma City, OK 73169.

Comments regarding this publication should be sent, in email form, to the following address: 9-AMC-AFS420-IPH@faa.gov

John S. Duncan

Director, Flight Standards Service

Preface
iv

The following individuals and their organizations are gratefully acknowledged for their valuable contribution and 

commitment to the publication of this handbook:

FAA: Project Managers: Lt Col James Rose and Maj Brian Strack (USAF); Assistant Project Manager: Gilbert Baker; 

Editor: Tara Savage; Technical Illustrator: Melissa Spears; Subject Matter Experts: Dean Alexander, John Bickerstaff, 

Barry Billmann, John Blair, John Bordy, Larry Buehler, Dan Burdette, Kel Christianson, Jack Corman, Rick Dunham, 

Dave Eckles, Gary Harkness, Hooper Harris, Harry Hodges, John Holman, Bob Hlubin, Gerry Holtorf, Steve Jackson, 

Scott Jerdan, Alan Jones, Norm Le Fevre, Barry Miller, John Moore, T.J. Nichols, Jim Nixon, Dave Olsen, Don Pate, Gary 

Powell, Phil Prasse, Larry Ramirez, Mark Reisweber, Dave Reuter, Jim Seabright, Eric Secretan, Ralph Sexton, Tom 

Schneider, Lou Volchansky, Dan Wacker, Mike Webb, and Mike Werner.

The Instrument Procedures Handbook was produced by the Federal Aviation Administration (FAA) with the assistance 

of Safety Research Corporation of America (SRCA). 

The FAA also wishes to acknowledge the following contributors:

Aircraft Owners and Pilots Association (www.aopa.org) for image used in chapter 5.

Volpe National Transportation Systems Center (www.volpe.dot.gov) for image used in chapter 5. 

Gary and Cecil Tweets at ASAP, Inc. (www.asapinc.net) for image used in chapter 1. 

The staff of the U.S. Air Force Advanced Instrument School (HQ AFFSA/AIS) for various inputs.

Acknowledgments
v

The United States Government does not endorse products or manufacturers. Trade or manufacturers’ names appear

herein solely because they are considered essential to the objective of this handbook.

Notice
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vii

Preface.............................................................................................. iii

Acknowledgments....................................................................... iv

Table of Contents........................................................................vii

Chapter 1

Departure Procedures.............................................................1-1

Introduction ...............................................................................1-1

Surface Movement Safety......................................................1-2

Airport Sketches and Diagrams.......................................1-2

Airport Facility Directory (A/FD) ......................................1-2

Surface Movement Guidance Control System 

(SMGCS)....................................................................................1-3

Advanced Surface Movement Guidance Control 

System (A-SMGCS)................................................................1-4

Airport Signs, Lighting, and Markings.......................1-4

Runway Incursions................................................................1-5

Runway Hotspots..................................................................1-6

Standardized Taxi Routes...................................................1-6

Taxi and Movement Operations Change .................1-6

Weather and the Departure Environment .......................1-8

Takeoff Minimums................................................................1-8

Takeoff Minimums for Commercial Operators...........1-8

Operations Specifications (OpSpecs).............................1-8

Ceiling and Visibility Requirements..............................1-10

Visibility .............................................................................1-10

Prevailing Visibility .........................................................1-10

Runway Visibility Value (RVV).....................................1-10

Tower Visibility.................................................................1-10

Runway Visual Range (RVR).........................................1-10

Adequate Visual Reference .........................................1-11

Ceilings...............................................................................1-11

Automated Weather Systems.........................................1-11

Automatic Terminal Information Service 

(ATIS)....................................................................................1-12

Digital Automatic Terminal Information 

Service (D-ATIS) ...............................................................1-12

IFR Alternate Requirements........................................1-12

Alternate Minimums for Commercial 

Operators...........................................................................1-14

Departure Procedures...........................................................1-14

Design Criteria......................................................................1-14

Low, Close-In Obstacles................................................1-17

One-Engine-Inoperative (OEI) Takeoff 

Obstacle Clearance Requirements ..........................1-19

Categories of Departure Procedures................................1-22

Obstacle Departure Procedures (ODPs)......................1-22

ODP Flight Planning Considerations.......................1-23

Standard Instrument Departures (SIDs).................1-23

Transition Routes............................................................1-26

SID Flight Planning Considerations..........................1-26

Area Navigation (RNAV) Departures........................1-30

SID Altitudes ....................................................................1-36

 Pilot Responsibility for Use of RNAV

 Departures.........................................................................1-36

Radar Departures................................................................1-37

Diverse Vector Area ............................................................1-38

Visual Climb Over Airport (VCOA).................................1-38

Noise Abatement Procedures.........................................1-42

Procedural Notes.....................................................................1-42

DP Responsibilities.............................................................1-42

Departures From Tower-Controlled Airports............1-43

Departures From Airports Without an Operating 

Control Tower.......................................................................1-43

Ground Communication Outlet.....................................1-43

See and Avoid Techniques...............................................1-43

VFR Departures....................................................................1-44

Chapter 2

En Route Operations................................................................2-1

Introduction ................................................................................2-1

En Route Navigation.................................................................2-2

Airways.....................................................................................2-2

Air Route Traffic Control Centers.....................................2-3

Safe Separation Standards.................................................2-4

Sectors..................................................................................2-5

In-flight Requirements and Instructions..................2-6

High Altitude Area Navigation Routing........................2-7

Table of Contents
viii

Preferred IFR Routes.............................................................2-7

Substitute Airway or Route Structures..........................2-9

Substitute Airway En Route Flight Procedures......2-9

Tower En Route Control....................................................2-10

Tower En Route Control Route Descriptions........2-10

Airway and Route System ....................................................2-13

Airway/Route Depiction...................................................2-13

IFR En Route Low Altitude Chart...............................2-14

IFR En Route High Altitude Chart .............................2-17

VHF Airways..........................................................................2-18

Victor Airway Navigation Procedures......................2-18

LF/MF Airways......................................................................2-18

En Route Obstacle Clearance Areas..............................2-18

Primary and Secondary En Route Obstacle 

Clearance Areas...............................................................2-19

Changeover Points.............................................................2-20

Direct Route Flights............................................................2-21

Published RNAV Routes....................................................2-23

Composition of Designators.......................................2-23

Use of Designators in Communications.................2-24

Random RNAV Routes.......................................................2-25

Off-Airway Routes...............................................................2-26

Off-Route Obstruction Clearance Altitude............2-27

Monitoring of Navigation Facilities..............................2-29

Navigational Gaps...............................................................2-29

NAVAID Accuracy Check...................................................2-29

VOR Accuracy...................................................................2-29

VOT.......................................................................................2-30

VOR Checkpoint Signs..................................................2-31

Dual VOR Check...............................................................2-31

Airborne VOR Check ......................................................2-31

NDB Accuracy Check .....................................................2-31

RNAV Accuracy Check...................................................2-32

Waypoints..................................................................................2-31

User-Defined Waypoints...................................................2-32

Floating Waypoints.............................................................2-32

Computer Navigation Performance .................................2-33

Required Navigation Performance ...................................2-34

RNP Levels.............................................................................2-35

Standard RNP Levels......................................................2-35

Application of Standard RNP Levels........................2-35

IFR En Route Altitudes...........................................................2-35

Minimum En Route Altitude (MEA) ..............................2-35

RNAV Minimum En Route Altitude...............................2-35

Minimum Reception Altitude (MRA)............................2-35

Maximum Authorized Altitude (MAA).........................2-36

Minimum Obstruction Clearance Altitude 

(MOCA)....................................................................................2-36

Minimum Turning Altitude (MTA) .................................2-38

Minimum Crossing Altitude (MCA)...............................2-40

Minimum IFR Altitude (MIA)............................................2-40

Minimum Vectoring Altitudes (MVA)...........................2-41

IFR Cruising Altitude or Flight Level.............................2-42

Reduced Vertical Separation Minimums 

(RSVM).....................................................................................2-43

Cruise Clearance..................................................................2-43

Lowest Usable Flight Level ..............................................2-43

Operations in Other Countries.......................................2-44

Altitude Above Ground (QFE).........................................2-45

Barometric Pressure for Standard

Altimeter Settings (QNE)...................................................2-45

Barometric Pressure for Local

Altimeter Settings (QNH)..................................................2-45

En Route Reporting Procedures ........................................2-46

Non-Radar Position Reports............................................2-46

Flights in a Radar Environment......................................2-46

Position Report Items........................................................2-46

Additional Reports.........................................................2-47

Communication Failure.........................................................2-47

ARTCC Radio Frequency Outage...................................2-48

Climbing and Descending En Route ................................2-48

Aircraft Speed and Altitude.............................................2-49

En Route Holding Procedures.............................................2-51

ATC Holding Instructions.................................................2-51

Maximum Holding Speed................................................2-52

High Performance Holding .............................................2-52

En Route Safety Considerations.........................................2-52

Fuel State Awareness.........................................................2-52

Diversion Procedures.........................................................2-52

Chapter 3

Arrivals...........................................................................................3-1

Introduction ................................................................................3-1

Navigation in the Arrival Environment..............................3-2

Descent Planning..................................................................3-3

Vertical Navigation (VNAV) Planning.............................3-4

LNAV/VNAV Equipment......................................................3-6

Descent Planning for High Performance Aircraft......3-6

Descending From the En Route Altitude......................3-8

Controlled Flight Into Terrain (CFIT)...............................3-9

Standard Terminal Arrival Routes (STARs) ......................3-10

RNAV STARs or STAR Transitions....................................3-12

Interpreting the STAR ........................................................3-12

STAR Procedures .................................................................3-16

Preparing for the Arrival........................................................3-16

Reviewing the Approach..................................................3-16

Altitude ..................................................................................3-16

Airspeed ................................................................................3-20

Holding Patterns.................................................................3-21
ix

Approach Clearance...........................................................3-22

Present Position Direct......................................................3-24

Radar Vectors to Final Approach Course ...................3-24

Special Airport Qualification...............................................3-26

Chapter 4

Approaches.................................................................................4-1

Introduction ................................................................................4-1

Approach Planning ..................................................................4-2

Weather Considerations ........................................................4-2

Weather Sources ..................................................................4-2

Broadcast Weather ...............................................................4-5

Automated Terminal Information Service (ATIS) .......4-5

Automated Weather Observing Programs..................4-5

Automated Weather Observing System...................4-5

Automated Surface Observing System (ASOS)/

Automated Weather Sensor System (AWSS) ..........4-5

Center Weather Advisories (CWA)...................................4-6

Weather Regulatory Requirements ...............................4-6

Weather Requirements and Part 91 Operators..........4-6

Weather Requirements and Part 135 Operators........4-7

Weather Requirements and Part 121 Operators .......4-7

Aircraft Performance Considerations.................................4-7

Airplane Performance Operating Limitations............4-7

Aircraft Approach Categories...........................................4-8

Instrument Approach Charts................................................4-9

Approach Chart Naming Conventions .........................4-9

Straight-In Procedures .......................................................4-9

Circling Only Procedures .................................................4-11

Communications ....................................................................4-11

Approach Control ..............................................................4-13

Air Route Traffic Control Center (ARTCC)....................4-13

High or Lack of Minimum Vectoring 

Altitudes (MVAs)..............................................................4-14

Lack of Approach Control Terrain Advisories........4-15

Airports With an ATC Tower ............................................4-15

Airports Without A Control Tower ................................4-15

Primary NAVAID.......................................................................4-17

Equipment Requirements....................................................4-17

Courses........................................................................................4-17

Traditional Courses ............................................................4-17

Area Navigation Courses .................................................4-18

Altitudes ....................................................................................4-19

Minimum Safe Altitude ....................................................4-19

Final Approach Fix Altitude ............................................4-19

Minimum Descent Altitude (MDA), Decision 

Altitude (DA), And Decision Height (DH)....................4-20

Enhanced Flight Vision Systems (EFVS) and

Instrument Approaches........................................................4-21 

Vertical Navigation..................................................................4-23

Wide Area Augmentation System ................................4-23

Benefits Of WAAS In The Airport Environment

Advantages Of WAAS Enabled LPV 

Approaches.......................................................................4-25

Ground-Based Augmentation System (GBAS)..........4-26

Required Navigation Performance (RNP)...................4-26

RNAV Approach Authorization .....................................4-30

Baro-VNAV.........................................................................4-31

Hot and Cold Temperature 

Limitations ....................................................................... 4-31

LNAV, LNAV/VNAV and

Circling Minimums......................................................... 4-33

Airport/Runway Information...............................................4-33

Instrument Approach Procedure (IAP) Briefing............4-33

Navigation and Communication Radios ...................4-33

Flight Management System (FMS)................................4-35

Autopilot Modes ................................................................4-35

Descents.....................................................................................4-36

Stabilized Approach ..........................................................4-36

Descent Rates and Glidepaths for Nonprecision 

Approaches ..........................................................................4-37

Maximum Acceptable Descent Rates......................4-37

Transition to a Visual Approach .....................................4-39

Missed Approach ...............................................................4-39

Example Approach Briefing ...........................................4-46

Instrument Approach Procedure Segments..................4-49

Feeder Routes ......................................................................4-49

Terminal Routes ..................................................................4-50

DME Arcs ...............................................................................4-50

Course Reversal ..................................................................4-51

Initial Approach Segment ...............................................4-53

Intermediate Approach Segment.................................4-53

Final Approach Segment .................................................4-54

Missed Approach Segment ............................................4-54

Approach Clearance ..........................................................4-54

Vectors To Final Approach Course ...............................4-54

Nonradar Environment ....................................................4-56

Types of Approaches..............................................................4-56

Visual and Contact Approaches ....................................4-56

Visual Approaches..............................................................4-57

Contact Approaches..........................................................4-59

Charted Visual Flight Procedures .................................4-59

RNAV Approaches ..............................................................4-59

Terminal Arrival Areas .......................................................4-62

RNAV Approach Types.......................................................4-62

GPS Overlay of Nonprecision Approach.....................4-62

GPS Stand-Alone/RNAV (GPS) Approach....................4-64

RNAV (GPS) Approach Using WAAS..............................4-68

ILS Approaches ...................................................................4-68

ILS Approach Categories..................................................4-71

CAT II and III Approaches .................................................4-71
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ILS Approaches To Parallel Runways ...........................4-71

Parallel (Dependent) ILS Approaches..........................4-71

Simultaneous Parallel ILS Approaches........................4-71

Simultaneous Close Parallel ILS Precision 

Runway Monitor Approaches.........................................4-77

Simultaneous Offset Instrument Approaches 

(SOIAs).....................................................................................4-79

Converging ILS Approaches............................................4-80

VOR Approach .....................................................................4-80

NDB Approach ....................................................................4-84

Radar Approaches .............................................................4-84

Precision Approach Radar (PAR)....................................4-87

Airport Surveillance Radar (ASR) ..................................4-87

Localizer Approaches .......................................................4-87

Localizer and Localizer DME ...........................................4-87

Localizer Back Course .......................................................4-87

Localizer-Type Directional Aid (LDA)............................4-88

Simplified Directional Facility (SDF).............................4-88

Chapter 5

Improvement Plans..................................................................5-1

Introduction ................................................................................5-1

Next Generation Air Transportation (NextGen) 

System...........................................................................................5-2

NextGen Existing Improvements....................................5-3

Benefits of NextGen.............................................................5-6

Head-Up Displays (HUD).........................................................5-7

Synthetic Vision System (SVS)......................................5-8

Enhanced Flight Vision System (EFVS)......................5-8

Developing Combined Technology ..........................5-9

Electronic Flight Bag (EFB)................................................. 5-9

Access to Special Use Airspace ..................................... 5-10

 Civilians Using Special Use Airspace........................ 5-11

Chapter 6

Airborne Navigation Databases...........................................6-1

Introduction ...............................................................................6-1

Airborne Navigation Database Standardization............6-3

ARINC 424................................................................................6-4

Fix Records..........................................................................6-4

Simple Route Records.....................................................6-4

Complex Route Records.................................................6-5

Miscellaneous Records...................................................6-5

Path and Terminator Concept...............................................6-5

Path and Terminator Legs..................................................6-5

Path and Terminator Limitations.................................6-9

Role of the Database Provider............................................6-13

Role of the Avionics Manufacturer...............................6-13

Users Role ..............................................................................6-14

Operational Limitations of Airborne Navigation 

Databases...................................................................................6-14

Closed Indefinitely Airports............................................6-15

Storage Limitations............................................................6-15

Charting/Database Inconsistencies.............................6-15

Naming Conventions....................................................6-15

Issues Related To Magnetic Variation ......................6-16

Issues Related To Revision Cycle................................6-17

Chapter 7

Helicopter Instrument Procedures......................................7-1

Introduction ................................................................................7-1

Helicopter Instrument Flight Rule (IFR) 

Certification ................................................................................7-2

Flight and Navigation Equipment...................................7-2

Miscellaneous Requirements ...........................................7-2

Stabilization and Automatic Flight Control 

System (AFCS) .......................................................................7-2

Helicopter Flight Manual Limitations ...........................7-3

Operations Specifications .................................................7-5

Minimum Equipment List (MEL)......................................7-5

Pilot Proficiency ....................................................................7-5

Helicopter VFR Minimums ................................................7-8

Helicopter IFR Takeoff Minimums ..................................7-8

Helicopter IFR Alternates ...................................................7-8

Part 91 Operators .............................................................7-8

Part 135 Operators ..........................................................7-9

Helicopter Instrument Approaches ...............................7-9

Standard Instrument Approach Procedures to an 

Airport .................................................................................7-9

Copter Only Approaches to An Airport or 

Heliport ..................................................................................7-10

Copter GPS Approaches to an Airport or 

Heliport ..................................................................................7-10

Helicopter Approaches to VFR Heliports ...................7-14

Approach to a PinS ............................................................7-14

Approach to a Specific VFR Heliport............................7-14

Inadvertent IMC...................................................................7-16

IFR Heliports..........................................................................7-17

Appendix A

Emergency Procedures ..........................................................A-1

Introduction ...............................................................................A-1

Emergencies ...............................................................................A-1

Inadvertent Thunderstorm Encounter..........................A-1

Inadvertent Icing Encounter.............................................A-2

Precipitation Static ..............................................................A-2

Aircraft System Malfunction..................................................A-2

Generator Failure ..................................................................A-3
xi

Instrument Failure ................................................................A-3

Pitot/Static System Failure.................................................A-3

Loss of Situational Awareness (SA) .....................................A-3

Inadvertent Instrument Meteorological Condition 

(IIMC)..............................................................................................A-4

Maintaining Aircraft Control .............................................A-4

ATC Requirements During an In-Flight Emergency......A-4

Provide Information.............................................................A-5

Radar Assistance....................................................................A-5

Emergency Airport ..............................................................A-5

Emergency Obstruction Video Map (EOVM)...............A-6

Responsibility.........................................................................A-6

Escort ........................................................................................A-6

Appendix B

Acronyms.....................................................................................B-1

Glossary.....................................................................................G-1

Index............................................................................................. I-1
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1-1

Introduction 

Thousands of instrument flight rules (IFR) takeoffs and

departures occur daily in the National Airspace System

(NAS). In order to accommodate this volume of IFR traffic, air

traffic control (ATC) must rely on pilots to use charted airport

sketches and diagrams, as well as departure procedures

(DPs) that include both standard instrument departures

(SIDs) and obstacle departure procedures (ODPs). While

many charted (and uncharted) departures are based on

radar vectors, the bulk of IFR departures in the NAS require

pilots to navigate out of the terminal environment to the

en route phase.

Departure Procedures

Chapter 1
1-2

Figure 1-1. Airport diagram included on the Oshkosh, Wisconsin 

VOR RWY 9 Approach Chart as depicted in the IFR TPP.

NOT FOR NAVIGATION

Runway numbers

Runway slope

Runway length and width

IFR takeoffs and departures are fast-paced phases of 

flight, and pilots often are overloaded with critical flight 

information. While preparing for takeoff, pilots are busy 

requesting and receiving clearances, preparing their aircraft 

for departure, and taxiing to the active runway. During IFR 

conditions, they are doing this with minimal visibility, and 

they may be without constant radio communication if flying 

out of a non-towered airport. Historically, takeoff minimums 

for commercial operations have been successively reduced 

through a combination of improved signage, runway 

markings and lighting aids, and concentrated pilot 

training and qualifications. Today at major terminals, some 

commercial operators with appropriate equipment, pilot 

qualifications, and approved Operations Specifications 

(OpSpecs) may takeoff with visibility as low as 300 feet 

runway visual range (RVR). One of the consequences of 

takeoffs with reduced visibility is that pilots are challenged 

in maintaining situational awareness during taxi operations.

Surface Movement Safety

One of the biggest safety concerns in aviation is the surface 

movement accident. As a direct result, the Federal Aviation 

Administration (FAA) has rapidly expanded the information 

available to pilots, including the addition of taxiway and 

runway information in FAA publications, particularly the 

IFR U.S. Terminal Procedures Publication (TPP) booklets and 

Airport/Facility Directory (A/FD) volumes. The FAA has also 

implemented new procedures and created educational and 

awareness programs for pilots, ATC, and ground operators. 

By focusing resources to attack this problem head on, the 

FAA hopes to reduce and eventually eliminate surface 

movement accidents.

Airport Sketches and Diagrams

Airport sketches and diagrams provide pilots of all levels 

with graphical depictions of the airport layout. National 

Aeronautical Products (AeroNav Products), formerly known 

as The National Aeronautical Charting Office (NACO), 

provide an airport sketch on the lower left or right portion 

of every instrument approach chart. [Figure 1-1] This sketch 

depicts the runways, their length, width and slope, the 

touchdown zone elevation, the lighting system installed on 

the end of the runway, and taxiways. Graphical depictions 

of NOTAMS are also available for selected airports as well as 

for temporary flight restriction (TFRs) areas on the defense 

internet NOTAM service (DINS) website.

For select airports, typically those with heavy traffic or 

complex runway layouts, AeroNav Products also print 

an airport diagram. The diagram is located in the IFR TPP 

booklet following the instrument approach chart for a 

particular airport. It is a full page depiction of the airport 

that includes the same features of the airport sketch plus 

additional details, such as taxiway identifiers, airport latitude 

and longitude, and building identification. The airport 

diagrams are also available in the A/FD and on the AeroNav 

Products website at www.aeronav.faa.gov. [Figure 1-2]

Airport Facility Directory (A/FD)

A/FD, published in regional booklets by AeroNav Products, 

provides textual information about all airports, both visual 

flight rules (VFR) and IFR. The A/FD includes runway length 

and width, runway surface, load bearing capacity, runway 

slope, runway declared distances, airport services, and 

hazards, such as birds and reduced visibility. [Figure 1-3] 

Sketches of airports also are being added to aid VFR pilots in 

surface movement activities. In support of the FAA Runway 

Incursion Program, full page airport diagrams and “Hot 

Spot” locations are included in the A/FD. These charts are 

the same as those published in the IFR TPP and are printed 

for airports with complex runway or taxiway layouts.
1-3

Figure 1-2. Airport diagram of Oshkosh, Wisconsin as depicted 

in the A/FD.

EC-3, 29 JUL 2010 to 26 AUG 2010

EC-3, 29 JUL 2010 to 26 AUG 2010

NOT FOR NAVIGATION

Longitude and latitude

Airport name and location On-airport buildings

Taxiway designations

Precise runway direction

Runway slope

Surface Movement Guidance Control System 

(SMGCS)

The Surface Movement Guidance Control System (SMGCS) 

was developed in 1992 to facilitate the safe movement of 

aircraft and vehicles at airports where scheduled air carriers 

were conducting authorized operations. This program was 

designed to provide guidelines for the creation of low 

visibility taxi plans for all airports with takeoff or landing 

operations using visibility minimums less than 1,200 feet 

RVR. For landing operations, this would be pertinent only to 

those operators whose OpSpecs permit them to land with 

lower than standard minimums. For departures, however, 

since there are no regulatory takeoff minimums for Title 14

Code of Federal Regulations (14 CFR) Part 91 operators, 

the SMGCS information is pertinent to all departing 

traffic operating in instrument meteorological conditions 

(IMC). Advisory Circular (AC) 120-57, Surface Movement 

Guidance and Control System, outlines the SMGCS program 

in its entirety including standards and guidelines for 

establishment of a low visibility taxi plan.

The SMGCS low visibility taxi plan includes the improvement 

of taxiway and runway signs, markings, and lighting, 

as well as the creation of SMGCS visual aid diagrams. 

[Figure 1-4] The plan also clearly identifies taxi routes 

and their supporting facilities and equipment. Airport 

enhancements that are part of the SMGCS program include, 

but are not limited to:

•	 Stop bar lights—required at intersections of an 

illuminated (centerline or edge lighted) taxiway 

and an active runway for operations less than 

600 feet RVR. These lights consist of a row of red 

unidirectional, in- pavement lights installed along 

the holding position marking. When extinguished by 

the controller, they confirm clearance for the pilot, 

or vehicle operator, to enter the runway. Controlled 

stop bars operate in conjunction with green/yellow 

centerline lead-on lights that extend from the stop 

bar location onto the runway.

•	 Taxiway centerline lead-on lights—guide ground 

traffic under low visibility conditions and at night. 

These lights consist of alternating green/yellow inpavement lights.

•	 Runway guard lights—either elevated or inpavement, may be installed at all taxiways that 

provide access to an active runway. They consist 

of alternately flashing yellow lights. These lights 

are used to denote both the presence of an active 

runway and identify the location of a runway holding 

position marking.

•	 Geographic position markings—ATC verifies the 

position of aircraft and vehicles using geographic 

position markings. The markings can be used either 

as hold points or for position reporting. These 

checkpoints or “pink spots” are outlined with a black 

and white circle and designated with a number or a 

number and a letter.

•	 Clearance bar lights—three yellow in-pavement

clearance bar lights used to denote holding 

positions for aircraft and vehicles. When used for 

hold points, they are co-located with geographic 

position markings.

Both flight and ground crews, Part 121 and 135 operators, are 

required to comply with SMGCS plans when implemented 

at their specific airport. All airport tenants are responsible 

for disseminating information to their employees and 

conducting training in low visibility operating procedures. 

Anyone operating in conjunction with the SMGCS plan 

must have a copy of the low visibility taxi route chart for 

their given airport as these charts outline the taxi routes 

and other detailed information concerning low visibility 

operations. These charts are available from private sources 
1-4

Figure 1-3. Excerpts from the Airport Facility Directory of Naples Muni, Naples, Florida.

outside of the FAA. Government sources for SMGCS 

charts may be available in the future. Part 91 operators 

are expected to comply with the guidelines listed in AC 

120-57, and should expect “Follow Me” service (when 

available) when low visibility operations are in use. Any 

SMGCS outage that would adversely affect operations at 

the airport is issued as a Notice to Airmen (NOTAM).

Advanced Surface Movement Guidance Control 

System (A-SMGCS)

With the increasing demand for airports to accommodate 

higher levels of aircraft movements, it is becoming more 

and more difficult for the existing infrastructure to safely 

handle greater capacities of traffic in all weather conditions. 

As a result, the FAA is implementing runway safety systems, 

such as Airport Surface Detection Equipment-Model X 

(ASDE-X) and Advanced Surface Movement Guidance and 

Control System (A-SMGCS) at various airports. The data that 

these systems use comes from surface movement radar 

and aircraft transponders. The combination of these data 

sources allows the systems to determine the position and 

identification of aircraft on the airport movement area and 

decreases the potential of collisions on airport runways 

and taxiways.

Additional information concerning airport lighting, 

markings, and signs can be found in the Aeronautical 

Information Manual (AIM), Chapter 14, “Runway Incursion 

Avoidance” in the Pilot’s Handbook of Aeronautical 

Knowledge as well as on the FAA’s website at http://www.

faa.gov/airports/runway_safety/.

Airport Signs, Lighting, and Markings

Flight crews use airport lighting, markings, and signs to 

help maintain situational awareness. These visual aids 

provide information concerning the aircraft’s location on 

the airport, the taxiway in use, and the runway entrance 

being used. Overlooking this information can lead to 

ground accidents that are entirely preventable. If you 

encounter unfamiliar markings or lighting, contact ATC 

for clarification and, if necessary, request progressive taxi 

instructions. Pilots are encouraged to notify the appropriate 

authorities of erroneous, misleading, or decaying signs or 

lighting that would contribute to the failure of safe ground 

operations.
1-5

Figure 1-4. Key airport lighting and markings.

A A

81

18

Runway holding position marking and lights for land and hold short operations (LAHSO)

Painted taxiway direction sign

Painted taxiway location sign

Taxiway centerline marking

Under ATC Not under ATC control

control

Taxiway edge marking (do not cross)

Centerline/lead-on lights

Stop bar at instrument landing system hold position

Broken taxiway edge markings may be crossed

Painted

holding

position

sign

Low 

visibility

hold

point

Vehicle lanes

Reporting points

In-pavement runway guard lights

Runway Incursions

On any given day, the NAS may handle almost 200,000 

takeoffs and landings. Due to the complex nature of the 

airport environment and the intricacies of the network of 

people that make it operate efficiently, the FAA is constantly 

looking to maintain the high standard of safety that exists 

at airports today. Runway safety is one of its top priorities. 

Beginning FY 2008, the FAA defines a runway incursion as: 

“Any occurrence at an aerodrome involving the incorrect 

presence of an aircraft, vehicle, or person on the protected 

area of a surface designated for the landing and takeoff of 

aircraft.”

The four categories of runway incursions are listed below:

•	 Category A—a serious incident in which a collision

was narrowly avoided.
1-6

Figure 1-5. FAA recommendations for reducing runway incursions.

The FAA recommends that you:

• Receive and understand all NOTAMs, particularly 

 those concerning airport construction and lighting.

• Read back, in full, all clearances involving 

 holding short, line up and wait, and crossing runways

 to ensure proper understanding.

• Abide by the sterile cockpit rule.

• Develop operational procedures that minimize 

 distractions during taxiing.

• Ask ATC for directions if you are lost or unsure of 

 your position on the airport.

• Adhere to takeoff and runway crossing clearances in 

 a timely manner.

• Position your aircraft so landing traffic can see you.

• Monitor radio communications to maintain a 

 situational awareness of other aircraft.

• Remain on frequency until instructed to change.

• Make sure you know the reduced runway distances 

 and whether or not you can comply before accepting 

 a land and hold short clearance or clearance for

 shortened runway.

• Report confusing airport diagrams to the proper 

 authorities.

• Use exterior taxi and landing lights when practical.

 

The sterile cockpit rule refers to a concept outlined in 14 CFR 

Part 121, sections 121.542 and 135.100 that requires ight 

crews to refrain from engaging in activities that could distract 

them from the performance of their duties during critical phases 

of ight.

NOTE:

•	 Category B—an incident in which separation

decreases and there is a significant potential for 

collision that may result in a time critical corrective/

evasive response to avoid a collision. 

•	 CategoryC—anincidentcharacterizedbyampletime

and/or distance to avoid a collision. 

•	 Category D—an incident that meets the definition

of runway incursion, such as incorrect presence of a 

single vehicle/person/aircraft on the protected area 

of a surface designated for the landing and takeoff of 

aircraft but with no immediate safety consequences.

Figure 1-5 highlights several steps that reduce the chances 

of being involved in a runway incursion.

In addition to the SMGCS program, the FAA has implemented 

additional programs to reduce runway incursions and other 

surface movement issues. They identified runway hotspots, 

designed standardized taxi routes, and instituted the 

Runway Safety Program.

Runway Hotspots

ICAO defines runway hotspots as a location on an 

aerodrome movement area with a history or potential risk 

of collision or runway incursion and where heightened 

attention by pilots and drivers is necessary. Hotspots 

alert pilots to complex or potentially confusing taxiway 

geometry that could make surface navigation challenging. 

Whatever the reason, pilots need to be aware that 

these hazardous intersections exist, and they should 

be increasingly vigilant when approaching and taxiing 

through these intersections. These hotspots are depicted 

on some airport charts as circled areas. [Figure 1-6] The FAA 

Office of Runway Safety has links to the FAA regions that 

maintain a complete list of airports with runway hotspots 

at http://www.faa.gov/airports/runway_safety/.

Standardized Taxi Routes

Standard taxi routes improve ground management at highdensity airports, namely those that have airline service. At 

these airports, typical taxiway traffic patterns used to move 

aircraft between gate and runway are laid out and coded. 

The ATC specialist (ATCS) can reduce radio communication 

time and eliminate taxi instruction misinterpretation by 

simply clearing the pilot to taxi via a specific, named route. 

An example of this would be Los Angeles International 

Airport (KLAX), where North Route is used to transition 

to Runway 24L. [Figure 1-7] These routes are issued by 

ground control, and if unable to comply, pilots must 

advise ground control on initial contact. If for any reason 

the pilot becomes uncertain as to the correct taxi route, a 

request should be made for progressive taxi instructions. 

These step-by-step routing directions are also issued if the 

controller deems it necessary due to traffic, closed taxiways, 

airport construction, etc. It is the pilot’s responsibility to 

know if a particular airport has preplanned taxi routes, to 

be familiar with them, and to have the taxi descriptions 

in their possession. Specific information about airports 

that use coded taxiway routes is included in the Notice to 

Airmen Publication (NTAP).

Taxi and Movement Operations Change

As of June 30, 2010, controllers are required to issue explicit 

instructions to cross or hold short of each runway that 

intersects a taxi route. Following is a summary of these 

procedural changes: 

•	 “Taxi to” is no longer used when issuing taxi

instructions to an assigned takeoff runway. 

•	 Instructions to cross a runway are issued one at a

time. Instructions to cross multiple runways are not 

issued. An aircraft or vehicle must have crossed the 

previous runway before another runway crossing 

is issued. This applies to any runway, including 

inactive or closed runways.
1-7

Figure 1-6. Example of runway hot spots located at Long Beach/Daugherty Field Airport (KLGB).

At Long Beach/Daugherty Field Airport, the following areas have been 

designated as hot spots, posing a special challenge to pilots.

HOT1

Runway 25R and Taxiway D

Aircraft exiting runway 30 at taxiway A turn 

left on taxiway D, anticipate reaching their 

destination, and fail to hold short of runway 

25R.

HOT2

Runway 12 and Taxiway B

Aircraft northbound on taxiway B for departure 

on runway 16R at taxiway intersection D miss 

the right turn onto taxiway D and enter 

runways 12, 7L, and 25R.

HOT3

Runway 25L/7R at Taxiway B

Aircraft southbound on taxiway B anticipate 

reaching their destination parking ramp and 

fail to hold short of runway 25L/7R.

HOT4

Runway 16R/34L at Taxiway F

Aircraft taxiing to runway 16R from the 

southwest ramp miss the left turn onto 

taxiway B, continue eastbound onto taxiway 

F, and enter runway 16R/34L.

HOT5

Runway 25L at Taxiway D

After completing a runup on inactive runway 

34R, aircraft fail to hold short of runway 25L.

HOT6

Landing Runway 30

Be aware that this runway crosses every other available runway 

at the airport. When exiting the runway, pilots should make sure 

they are turning with a “lead-off” taxiline onto a taxiway and not 

onto another active runway.

Figure 1-7. Los Angeles International Airport diagram, North Route, and standardized taxi route.

0102 GUA 62 ot 0102 L UJ 92, 3- WS

SW-3, 29 JUL 2010 to 26 AUG 2010

NOT FOR NAVIGATION

Standardized Taxi Routes for Los Angeles 

International Airport (KLAX)

The following Standardized Taxi routes 

may be issued to all taxiing aircraft.

North Route

Taxi via Charlie (C) towards taxiway Sierra (S) taxi northbound on taxiway Sierra (S), 

and at Check-point-1 contact Ground Control on frequency 121.65, hold short of 

taxiway Delta (D). When advised by the north Ground Control, the North Route 

continues on taxiway Echo (E) to Runway 24L or the gate, whichever applies.

South Route

If the aircraft is west of taxiway Romeo (R), taxi eastbound on taxiway Echo (E) and 

turn right on taxiway Romeo (R), if the aircraft is east of taxiway Romeo (R), taxi 

westbound on taxiway Echo (E) and turn left on taxiway Romeo (R). And at 

Check-point-2, contact Ground Control on frequency 121.75, hold short of taxiway 

Charlie (C).

West Route

Taxi via taxiway Charlie (C) west-bound, hold short of taxiway Alfa Alfa (AA), contact 

Ground Control on frequency 121.65 when number one approaching Taxiway AA.

Bridge Route

Taxi via taxiway Echo (E) then south on taxiway Alfa Alfa (AA), and at Check-point-3 

contact Ground Control on frequency 121.75, hold short of taxiway Charlie (C). 

(AJV-W2 4/23/2010) SAMPLE NOT FOR ACTUAL USE 

North Route
1-8

•	 Never cross a runway hold marking without explicit

ATC instructions. If in doubt, ask!

Reminder: You may not enter a runway unless you have been: 

1. Instructed to cross or taxi onto that specific runway; 

2. Cleared to take off from that runway; or 

3. Instructed to line up and wait on that specific runway.

For more information on the change, refer to FAA Order N 

JO 7110.65, which can be found at www.faa.gov.

Weather and the Departure Environment

Takeoff Minimums

While mechanical failure is potentially hazardous during 

any phase of flight, a failure during takeoff under 

instrument conditions is extremely critical. In the event of 

an emergency, a decision must be made to either return to 

the departure airport or fly directly to a takeoff alternate. If 

the departure weather were below the landing minimums 

for the departure airport, the flight would be unable to 

return for landing, leaving few options and little time to 

reach a takeoff alternate.

In the early years of air transportation, landing minimums 

for commercial operators were usually lower than takeoff 

minimums. Therefore, it was possible that minimums 

allowed pilots to land at an airport but not depart from that 

airport. Additionally, all takeoff minimums once included 

ceiling, as well as visibility requirements. Today, takeoff 

minimums are typically lower than published landing 

minimums, and ceiling requirements are only included if 

it is necessary to see and avoid obstacles in the departure 

area.

The FAA establishes takeoff minimums for every airport 

that has published Standard Instrument Approaches. 

These minimums are used by commercially operated 

aircraft, namely Part 121 and Part 135 operators. At airports 

where minimums are not established, these same carriers 

are required to use FAA designated standard minimums: 

1 statute mile (SM) visibility for single- and twin-engine 

aircraft, and 1⁄2 SM for helicopters and aircraft with more 

than two engines.

Aircraft operating under 14 CFR Part 91 are not required to 

comply with established takeoff minimums. Legally, a zero/ 

zero departure may be made, but it is never advisable. If 

commercial pilots who fly passengers on a daily basis must 

comply with takeoff minimums, then good judgment and 

common sense would tell all instrument pilots to follow 

the established minimums as well.

AeroNav Products charts list takeoff minimums only for 

the runways at airports that have other than standard 

minimums. These takeoff minimums are listed by airport 

in alphabetical order in the front of the TPP booklet. If an 

airport has non-standard takeoff minimums, a (referred 

to by some as either the “triangle T” or “trouble T”) is placed 

in the notes sections of the instrument procedure chart. In 

the front of the TPP booklet, takeoff minimums are listed 

before the obstacle departure procedure. Some departure 

procedures allow a departure with standard minimums 

provided specific aircraft performance requirements are 

met. [Figure 1-8]

Takeoff Minimums for Commercial Operators

While Part 121 and Part 135 operators are the primary users 

of takeoff minimums, they may be able to use alternative 

takeoff minimums based on their individual OpSpecs. 

Through these OpSpecs, operators are authorized to depart 

with lower-than-standard minimums provided they have 

the necessary equipment and crew training.

Operations Specifications (OpSpecs)

Within the air transportation industry, there is a need to 

establish and administer safety standards to accommodate 

many variables. These variables include a wide range 

of aircraft, varied operator capabilities, the various 

situations requiring different types of air transportation, 

and the continual, rapid changes in aviation technology. 

It is impractical to address these variables through the 

promulgation of safety regulations for each and every 

type of air transport situation and the varying degrees of 

operator capabilities. Also, it is impractical to address the 

rapidly changing aviation technology and environment 

through the regulatory process. Safety regulations 

would be extremely complex and unwieldy if all possible 

variations and situations were addressed by regulation. 

Instead, the safety standards established by regulation 

should usually have a broad application that allows varying 

acceptable methods of compliance. The OpSpecs provide 

an effective method for establishing safety standards that 

address a wide range of variables. In addition, OpSpecs 

can be adapted to a specific certificate holder or operator’s 

class and size of aircraft and type and kinds of operations. 

OpSpecs can be tailored to suit an individual certificate 

holder or operator’s needs. 

Part 121 and Part 135 certificate holders have the ability, 

through the use of approved OpSpecs, to use lower-thanstandard takeoff minimums. Depending on the equipment 

installed in a specific type of aircraft, the crew training, and 

the type of equipment installed at a particular airport, these 

operators can depart from appropriately equipped runways 

with as little as 300 feet RVR. Additionally, OpSpecs outline 

T
1-9

Figure 1-8. Examples of non-standard takeoff minimums for Colorado Springs, Colorado.

C3

TAKE-OFFMINIMUMSAND(OBSTACLE)DEPARTUREPROCEDURES

10210

CANON CITY, CO

FREMONT COUNTY

TAKE-OFFMINIMUMS:Rwy 29, 4600-2or std.witha

min. climb of 450' perNM to 10400.

DEPARTUREPROCEDURE:Rwy11, climbrunway

heading.Rwy29,

AllaircraftinterceptandclimbviaPUBVORTAC

R-262(V244)PUBVORTACbeforeproceedingon

course.

CLAYTON, NM

CLAYTON MUNI

TAKE-OFF MINIMUMS: Rwy 30, 1300-1 or std.witha

min. climb of 244' perNM until 6700.

COLORADOSPRINGS,CO

CITY OF COLORADO SPRINGS MUNI

TAKE-OFFMINIMUMS:Rwy30,600-2or std.witha

min. climb of 220' perNM to 6900.

DEPARTUREPROCEDURE:Rwys12,17L,17R,turn

left. Rwys30,35L,35R,turnright.Allaircraft climb

directBRKVORTAC.Aircraft departing onBRK R-325

CWR-153 climb on course.Aircraft departingBRK

R-154 CWR-324 climb inBRKholding pattern (NW,

above14000.

CORTEZ, CO

CORTEZ MUNI (CEZ)

AMDT 3 10098 (FAA)

DEPARTUREPROCEDURE: use LEDVE

DEPARTURE.

CRAIG, CO

CRAIG-MOFFAT

TAKE-OFFMINIMUMS:Rwys7,25,800-1 ,or std.with

a min. climb of 400' per NM to 7000.

DEPARTUREPROCEDURE:Rwys7,25, climbdirect

climbing to: aircraft departing CHE R-213 CW R-296

departoncourse;allothers continueclimbingtocross

CHEatorabove;CHER-076CWR-11410500,R-115

CWR-21211300,andR-297CWR-07611300.

DEMING, NM

DEMING MUNI

TAKE-OFF MINIMUMS: Rwy 4,NA.

DEPARTUREPROCEDURE:WESTBOUND:Rwy8,

Rwy22, climbingright

Rwy26, climbingrightturnheading

course.EASTBOUND:Rwy8, climbdirectDMN

VORTAC; Rwys 22, 26, climbing right turn direct DMN

VORTAC;thenviaV94oncourse.NORTHBOUND:

Rwy8, climbdirectDMNVORTAC;Rwys22,26,

climbing right turn direct DMN VORTAC; then viaV110

oncourse.

DENVER,CO

CENTENNIAL (APA)

AMDT 4 08213 (FAA)

TAKE-OFF MINIMUMS:Rwy17L, std.w/min. climbof

Rwy17R,

perNM to 6900.

DEPARTUREPROCEDURE: Rwy10,whendeparting

DEN VOR/DME R-191 to DEN VOR/DME, thence ...

Rwys17L,17R,

DMER-196toDENVOR/DME,thence...Rwy 28,climb

endofrunway.Allother courses: climbingrightturn

DENVOR/DME,thence...Rwy35L, climbonaheading

VOR/DMER-208toDENVOR/DME,thence...Rwy

35R,

departureendofrunway.Allothercourses:climb

DENVOR/DME,thence...

...Climb inDENVOR/DMEholding pattern (hold south,

course.

NOTE:Rwy10,

Rwy17L,

Rwy17R,

fromdepartureendofrunway,842feetrightof

centerline,90'AGL/6021'MSL. Rwy28,terrain

Rwy35L,terrain

29 JUL 2010 to 26 AUG 2010

29 JUL 2010 to 26 AUG 201

SAMPLE NOT FOR 

ACTUAL USE 

0

SW-1,

2010

NOT FOR

NAVIGATION

Takeoff minimums

City and state location and airport name

Other-than-standard IFR takeoff minimums are published.
1-10

Figure 1-9. Examples of weather information of various flight 

information publications (FLIP).

SE-2, 29 JUL 2010 to 26 AUG 2010

SE-2, 29 JUL 2010 to 26 AUG 2010

2010 to 26 AUG 2010

NOT FOR NAVIGATION

Figure 1-10. RVR conversion table.

RVR (feet)

1,600

2,400

3,200

4,000

4,500

5,000

6,000

Visibility (sm)

 1/4

 1/2

 5/8

 3/4

 7/8

 1

 11/4

Conversion

provisions for approach minimums, alternate airports, and 

weather services in Volume III of FAA Order 8900.1, Flight 

Standards Information Management System (FSIMS).

Ceiling and Visibility Requirements

All takeoffs and departures have visibility minimums (some 

may have minimum ceiling requirements) incorporated 

into the procedure. There are a number of methods to 

report visibility and a variety of ways to distribute these 

reports, including automated weather observations. Flight 

crews should always check the weather, including ceiling 

and visibility information, prior to departure. Never launch 

an IFR flight without obtaining current visibility information 

immediately prior to departure. Further, when ceiling and 

visibility minimums are specified for IFR departure, both 

are applicable.

Weather reporting stations for specific airports across the 

country can be located by reviewing the A/FD. Weather 

sources along with their respective phone numbers and 

frequencies are listed by airport. Frequencies for weather 

sources, such as Automatic Terminal Information Service 

(ATIS), Digital Automatic Terminal Information Service 

(D-ATIS), Automated Weather Observing System (AWOS), 

Automated Surface Observing System (ASOS), and FAA 

Automated Flight Service Station (AFSS) are published on 

approach charts as well. [Figure 1-9]

Visibility 

Visibility is the ability, as determined by atmospheric 

conditions and expressed in units of distance, to see and 

identify prominent unlighted objects by day and prominent 

lighted objects by night. Visibility is reported as statute miles, 

hundreds of feet, or meters.

Prevailing Visibility

Prevailing visibility is the greatest horizontal visibility 

equaled or exceeded throughout at least half the horizon 

circle, which need not necessarily be continuous. Prevailing 

visibility is reported in statute miles or fractions of miles.

Runway Visibility Value (RVV)

Runway visibility value is the visibility determined for a 

particular runway by a transmissometer. A meter provides 

continuous indication of the visibility (reported in statute 

miles or fractions of miles) for the runway. RVV is used in lieu 

of prevailing visibility in determining minimums for a particular 

runway.

Tower Visibility

Tower visibility is the prevailing visibility determined from 

the airport traffic control tower at locations that also report 

the surface visibility.

Runway Visual Range (RVR)

Runway visual range is an instrumentally derived value, 

based on standard calibrations, that represents the 

horizontal distance a pilot sees down the runway from the 

approach end. It is based on the sighting of either high 

intensity runway lights or on the visual contrast of other 

targets, whichever yields the greater visual range. RVR, in 

contrast to prevailing or runway visibility, is based on what 

a pilot in a moving aircraft should see looking down the 

runway. RVR is horizontal visual range, not slant visual range. 

RVR is reported in hundreds of feet, so the values must be 

converted to SM if the visibility in SM is not reported. [Figure 
1-11

Figure 1-11. AWSS installation at Driggs-Reed, Idaho.

1-10] It is based on the measurement of a transmissometer 

made near the touchdown point of the instrument runway 

and is reported in hundreds of feet. RVR is used in lieu of 

RVV and/or prevailing visibility in determining minimums 

for a particular runway.

Types of RVR

The following are types of RVR that may be used:

•	 Touchdown RVR—the RVR visibility readout values 

obtained from RVR equipment serving the runway 

touchdown zone.

•	 Mid-RVR—the RVR readout values obtained from 

RVR equipment located near the runway midpoint .

•	 Rollout RVR—the RVR readout values obtained from 

RVR equipment located nearest the rollout end of 

the runway.

•	 Far End RVR—when four RVR visibility sensors (VS) 

are installed, the far end RVR VS is the touchdown 

RVR VS on the reciprocal runway. The far end sensor 

will serve as additional information. 

RVR is the primary visibility measurement used by Part

121 and Part 135 operators with specific visibility reports 

and controlling values outlined in their respective OpSpecs. 

Under their OpSpecs agreements, the operator must have 

specific, current RVR reports, if available, to proceed with an 

instrument departure. OpSpecs also outline which visibility 

report is controlling in various departure scenarios.

Adequate Visual Reference

Another set of lower-than-standard takeoff minimums is 

available to Part 121 and Part 135 operations as outlined in 

their respective OpSpecs document. When certain types of 

visibility reports are unavailable or specific equipment is out 

of service, the flight can still depart the airport if the pilot 

can maintain adequate visual reference. An appropriate 

visual aid must be available to ensure the takeoff surface 

can be continuously identified, and directional control can 

be maintained throughout the takeoff run. Appropriate 

visual aids include high intensity runway lights, runway 

centerline lights, runway centerline markings, or other 

runway lighting and markings. With adequate visual 

references and appropriate OpSpec approval, commercial 

operators may take off with a visibility of 1600 RVR or 1⁄4 

SM. 

Ceilings

Ceiling is the height above the earth’s surface of the lowest 

layer of clouds or obscuring phenomena that is reported as 

broken, overcast, or obscuration and not classified as thin 

or partial.

Automated Weather Systems

An automated weather system consists of any of the 

automated weather sensor platforms that collect weather 

data at airports and disseminate the weather information 

via radio and/or landline. The systems consist of the ASOS/

Automated Weather Sensor System (AWSS) and the AWOS. 

These systems are installed and maintained at airports 

across the United States by both government (FAA and 

National Weather Service (NWS)) and private entities. They 

are relatively inexpensive to operate because they require 

no outside observer, and they provide invaluable weather 

information for airports without operating control towers. 

[Figure 1-11] 

AWOS and ASOS/AWSS offer a wide variety of capabilities 

and progressively broader weather reports. Automated 

systems typically transmit weather every one to two 

minutes so the most up-to-date weather information is 

constantly broadcast. Basic AWOS includes only altimeter 

setting, wind speed, wind direction, temperature, and dew 

point information. More advanced systems, such as the 

ASOS/AWSS and AWOS-3, are able to provide additional 

information, such as wind speed, wind gust, wind direction, 

variable wind direction, temperature, dew point, altimeter 

setting, and density altitude. ASOS/AWSS stations providing 

service levels A or B also report RVR. The specific type of 

equipment found at a given facility is listed in the A/FD. 

[Figure 1-12]
1-12

The use of the aforementioned visibility reports and 

weather services are not limited for Part 91 operators. 

Part 121 and Part 135 operators are bound by their 

individual OpSpecs documents and are required to 

use weather reports that come from the NWS or other 

approved sources. While every operator’s specifications are 

individually tailored, most operators are required to use 

ATIS, RVR reports, and selected reports from automated 

weather stations. All reports coming from an AWOS-3 

station are usable for Part 121 and Part 135 operators. Each 

type of automated station has different levels of approval 

as outlined in individual OpSpecs. Ceiling and visibility 

reports given by the tower with the departure information 

are always considered official weather, and RVR reports are 

typically the controlling visibility reference.

Automatic Terminal Information Service (ATIS)

ATIS is another valuable tool for gaining weather 

information. ATIS is available at most airports that have an 

operating control tower, which means the reports on the 

ATIS frequency are only available during the regular hours

of tower operation. At some airports that operate part-time

towers, ASOS/AWSS information is broadcast over the 

ATIS frequency when the tower is closed. This service is 

available only at those airports that have both an ASOS/

AWSS on the field and an ATIS-ASOS/AWSS interface switch 

installed in the tower.

Each ATIS report includes crucial information about 

runways and instrument approaches in use, specific 

outages, and current weather conditions including 

visibility. Visibility is reported in statute miles and may 

be omitted if the visibility is greater than five miles. ATIS 

weather information comes from a variety of sources 

depending on the particular airport and the equipment 

installed there. The reported weather may come from a 

manual weather observer, weather instruments located 

in the tower, or from automated weather stations. This 

information, no matter the origin, must be from NWS 

approved weather sources for it to be used in the ATIS 

report.

Digital Automatic Terminal Information Service 

(D-ATIS)

The digital ATIS (D-ATIS) is an alternative method of 

receiving ATIS reports. The service provides text messages 

to aircraft, airlines, and other users outside the standard 

reception range of conventional ATIS via landline and data 

link communications to the flight deck. Aircraft equipped 

with data link services are capable of receiving ATIS 

information over their Aircraft Communications Addressing 

and Reporting System (ACARS) unit. This allows the pilots to 

read and print out the ATIS report inside the aircraft, thereby 

increasing report accuracy and decreasing pilot workload.

Also, the service provides a computer-synthesized voice 

message that can be transmitted to all aircraft within 

range of existing transmitters. The Terminal Data Link 

System (TDLS) D-ATIS application uses weather inputs 

from local automated weather sources or manually entered 

meteorological data together with preprogrammed menus 

to provide standard information to users. Airports with 

D-ATIS capability are listed in the A/FD.

It is important to remember that ATIS information is 

updated hourly and anytime a significant change in the 

weather occurs. As a result, the information is not the most 

current report available. Prior to departing the airport, you 

need to get the latest weather information from the tower. 

ASOS/ AWSS and AWOS also provide a source of current 

weather, but their information should not be substituted 

for weather reports from the tower.

IFR Alternate Requirements

On AeroNav Products charts, standard alternate minimums 

are not published. If the airport has other than standard 

alternate minimums, they are listed in the front of the 

approach chart booklet. The presence of a triangle with an 

A on the approach chart indicates the listing of alternate 

minimums should be consulted. Airports that do not qualify 

for use as an alternate airport are designated with an A 

N/A. [Figure 1-13]

The requirement for an alternate depends on the aircraft 

category, equipment installed, approach navigational aid 

(NAVAID), and forecast weather. For example, airports with 

only a global positioning system (GPS) approach procedure 

cannot be used as an alternate by TSO-C129/129A users even

though N/A has been removed from the approach 

chart. For select area navigation (RNAV) GPS and GPS 

approach procedures, the N/A is being removed so 

they may be used as an alternate by aircraft equipped 

A

A

Figure 1-12. A/FD entry for an AWOS station.

SAMPLE NOT FOR ACTUAL USE

WEATHER DATA SOURCES: AWOS-3 119.675 (704) 735-6954.

AWOS/ASOS/AWSS information
1-13

Figure 1-13. Examples of IFR alternate minimums.

INSTRUMENT APPROACH PROCEDURE CHARTS

 IFR ALTERNATE AIRPORT MINIMUMS

Standard alternate minimums for non precision approaches are 800-2 (NDB, VOR, LOC, TACAN, LDA,

VORTAC, VOR/DME, ASR or WAAS LNAV); for precision approaches 600-2 (ILS or PAR). Airports within

this geographical area that require alternate minimums other than standard or alternate minimums with

restrictions are listed below. NA - means alternate minimums are not authorized due to unmonitored facility

or absence of weather reporting service. Civil pilots see FAR 91. IFR Alternate Airport Minimums: Ceiling

and Visibility Minimums not applicable to USA/USN/USAF. Pilots must review the IFR Alternate Airport

Minimums Notes for alternate airfield suitability.

NAME ALTERNATE MINIMUMS NAME ALTERNATE MINIMUMS

AKRON, CO

COLORADO

PLAINS RGNL ................. RNAV (GPS) Rwy 11

NA when local weather not available.

ALAMOSA, CO

SAN LUIS VALLEY RGNL/

BERGMAN FIELD .............. RNAV (GPS) Rwy 2

RNAV (GPS) Rwy 20

NA when local weather not available.

ALBUQUERQUE, NM

ALBUQUERQUE INTL

SUNPORT ..................... VOR or TACAN Rwy 8

Categories A,B, 900-2; Category C, 900-2 ;

Category D, 900-2 ; Category E, 900-3.

CLAYTON, NM

CLAYTON MUNI AIRPARK ............ NDB Rwy 2

NDB Rwy 20

RNAV (GPS) Rwy 2

RNAV (GPS) Rwy 20

 NA when local weather not available.

Categories A, B, 900-2; Category C, 900-2 ,

Category D, 900-2 .

Category D, 800-2 .

COLORADO SPRINGS, CO

CITY OF COLORADO SPRINGS

MUNI .............................. ILS or LOC Rwy 17L

ILS or LOC Rwy 35L

ILS or LOC Rwy 35R

RNAV (GPS) Y Rwy 17L

RNAV (GPS) Y Rwy 17R 4

RNAV (RNP) Z Rwy 17R5

Categories A, B, 900-2; Category C, 900-2 ;

Category D, 900-2 .

ILS, Category D, 700-2.

NA when local weather not available. 4

Categories A, B, 1100-2; Categories C, D,

1100-3. 5Categories A, B, C, D, 800-2 .

CORTEZ, CO

CORTEZ MUNI ............ RNAV (GPS) Y Rwy 21

RNAV (GPS) Z Rwy 21

VOR Rwy 21

Category D, 900-3.

Categories A, B, 1300-2; Categories C, D,

1300-3.

CRAIG, CO

CRAIG-MOFFAT .................... VOR/DME Rwy 7

VOR Rwy 25

23 SEP 2010 to 21 O

C

T 2010

23 SEP 2010 to 21 O

C

T 2010

SAMPLE NOT FOR ACTUAL USE 

SW-1, 23 SEP 2010 to 21 OCT 2010

SW-1, 23 SEP 2010 to 21 OCT 2010

NOT FOR NAVIGATION

City and state location

Airport name and applicable approach

Other-than-standard IFR alternate minimums

Other-than-standard IFR alternate minimums are published.

with an approach approved Wide Area Augmentation 

System (WAAS) receiver. Because GPS is not authorized 

as a substitute means of navigation guidance when 

conducting a conventional approach at an alternate 

airport, if the approach procedure requires either distance 

measuring equipment (DME) or automatic direction finder 

(ADF), the aircraft must be equipped with the appropriate 

DME or ADF avionics in order to use the approach as an 

alternate.

For airplane 14 CFR Part 91 requirements, an alternate 

airport must be listed on IFR flight plans if the forecast 

weather at the destination airport, for at least 1 hour 

before and for 1 hour after the estimated time of arrival 

(ETA), the ceiling is less than 2,000 feet above the airport 

elevation, and the visibility is less than 3 SM. A simple way to 

remember the rules for determining the necessity of filing 

an alternate for airplanes is the “1, 2, 3 Rule.” For helicopter 

14 CFR Part 91, similar alternate filing requirements apply. 

An alternate must be listed on an IFR flight plan if at the ETA 

and for 1 hour after the ETA, the ceiling is at least 1,000 feet 

above the airport elevation, or at least 400 feet above the 

lowest applicable approach minima, whichever is higher, 

and the visibility is at least 2 SM. 

Not all airports can be used as alternate airports. An airport 

may not be qualified for alternate use if the airport NAVAID 

is unmonitored, or if it does not have weather reporting 

capabilities. For an airport to be used as an alternate, 

the forecast weather at that airport must meet certain 

qualifications at the ETA. Standard airplane alternate 

minimums for a precision approach are a 600-foot ceiling 

and a 2 SM visibility. For a non-precision approach, the 

minimums are an 800-foot ceiling and a 2 SM visibility. 

Standard alternate minimums apply unless higher alternate 

minimums are listed for an airport. For helicopters, alternate 

weather minimums are a ceiling of 200 feet above the 

minimum for the approach to be flown, and visibility at 
1-14

least 1 SM but never less than the minimum visibility for 

the approach to be flown.

Alternate Minimums for Commercial Operators

IFR alternate minimums for Part 121 and Part 135 operators 

are very specific and have more stringent requirements 

than Part 91 operators.

Part 121 operators are required by their OpSpecs and 

14 CFR Part 121, sections 121.617 and 121.625 to have 

a takeoff alternate airport for their departure airport in 

addition to their airport of intended landing if the weather 

at the departure airport is below the landing minimums 

in the certificate holder’s OpSpecs for that airport. The 

alternate must be within 2 hours flying time for an aircraft 

with three or more engines with an engine out in normal 

cruise in still air. For two engine aircraft, the alternate must 

be within 1 hour. The airport of intended landing may be 

used in lieu of an alternate provided that it meets all the 

requirements. Domestic Part 121 operators must also file 

for alternate airports when the weather at their destination 

airport, from 1 hour before to 1 hour after their ETA, is 

forecast to be below a 2,000-foot ceiling and/or less than 

3 miles visibility.

For airports with at least one operational navigational 

facility that provides a straight-in non-precision approach, 

a straight-in precision approach, or a circling maneuver 

from an instrument approach procedure determine the 

ceiling and visibility by:

•	 Adding400 feettothe authorizedCAT Iheight above

airport (HAA)/height above touchdown elevation 

(HAT) for ceiling.

•	 Adding one mile to the authorized CAT I visibility

for visibility minimums.

This is one example of the criteria required for Part 121 

operators when calculating minimums. Part 135 operators 

are also subject to their own specific rules regarding the 

selection and use of alternate minimums as outlined 

in their OpSpecs and 14 CFR Part 135, sections 135.219 

through 135.225, and are similar to those used by Part 

121 operators.

Typically, dispatchers who plan flights for these operators 

are responsible for planning alternate airports. The 

dispatcher considers aircraft performance, aircraft 

equipment and its condition, and route of flight when 

choosing alternates. In the event changes need to be made 

to the flight plan en route due to deteriorating weather, 

the dispatcher maintains contact with the flight crew 

and reroutes their flight as necessary. Therefore, it is the 

pilot’s responsibility to execute the flight as planned by 

the dispatcher; this is especially true for Part 121 pilots. To 

aid in the planning of alternates, dispatchers have a list of 

airports that are approved as alternates so they can quickly 

determine which airports should be used for a particular 

flight. Dispatchers also use flight planning software that 

plans routes including alternates for the flight. This type of 

software is tailored for individual operators and includes 

their normal flight paths and approved airports. Flight 

planning software and services are provided through 

private sources.

Though the pilot is the final authority for the flight 

and ultimately has full responsibility, the dispatcher is 

responsible for creating flight plans that are accurate and 

comply with the CFRs. Alternate minimum criteria are only 

used as planning tools to ensure the pilot in command and 

dispatcher are thinking ahead to the approach phase of 

flight. In the event the flight would actually need to divert 

to an alternate, the published approach minimums or 

lower-than-standard minimums must be used as addressed 

in OpSpecs documents.

Departure Procedures

Instrument departure procedures are preplanned IFR 

procedures that provide obstruction clearance from 

the terminal area to the appropriate en route structure. 

Primarily, these procedures are designed to provide obstacle 

protection for departing aircraft. There are two types of 

Departure Procedures (DPs): Obstacle Departure Procedures 

(ODPs) and Standard Instrument Departures (SIDs).

When an instrument approach is initially developed for an 

airport, the need for an ODP is assessed. If an aircraft may 

turn in any direction from a runway within the limits of the 

assessment area and remain clear of obstacles that runway 

passes what is called a diverse departure assessment, and 

no ODP is published. A diverse departure assessment 

ensures that a prescribed, expanding amount of required 

obstacle clearance (ROC) is achieved during the climb-out 

until the aircraft can obtain a minimum 1,000 feet ROC in 

non-mountainous areas or a minimum 2,000 feet ROC in 

mountainous areas. Unless specified otherwise, required 

obstacle clearance for all departures, including diverse, is 

based on the pilot crossing the departure end of the runway 

(DER) at least 35 feet above the DER elevation, climbing to 

400 feet above the DER elevation before making the initial 

turn, and maintaining a minimum climb gradient of 200 

feet per nautical mile (FPNM), unless required to level off 

by a crossing restriction until the minimum IFR altitude 

is reached. Following ODP assessment, a SID may still be 

established for the purposes of ATC flow management, 

system enhancement, or noise abatement. 
1-15

Figure 1-14. Previous TERPS departure procedures.

1 NM 2 NM

10 NM

200 feet

400 feet

V186

Positive course guidance must be acquired 

within 10 NM for straight departures and 

within 5 NM for departures requiring turns.

Required climb gradient of 200 FPNM 

Previous TERPS Departure Procedures

Obstacle clearance surface (OCS)

35 feet

152 feet

304 feet 96 feet

48 '

Figure 1-15. Diverse Departure Obstacle Assessment to 25/46 NM.

Beyond the diverse obstacle assessment

area (25/46 NM) there might be significantly 

higher obstacles.

Aircraft reaches en route obstacle 

clearance of 1,000' (nonmountainous 

areas) or 2,000' (in mountainous areas).

TERPS Design CG of 200 FPNM

40:1 OIS at 152 FPNM

4NM

25/46 NM
1-16

Figure 1-16. New TERPS departure procedures.

1 NM 2 NM

V186

15

200 feet

400 feet

First

Significant

Obstacle

Clearway TORA

TODA

TORA

ASDA

Stopway

75 Meters

(247 Feet)

Positive Course Guidance (PCG) 

A continuous display of navigational data 

that enables an aircraft to be flown along a 

specific course line (e.g., radar vector, 

RNAV, ground-based NAVAID). PCG must 

be acquired within 10 NM for straight 

departures and within 5 NM for departures 

requiring turns.

Departure End of Runway (DER) 

The end of runway available for the ground run of an aircraft 

departure. The end of the runway that is opposite the landing 

threshold, sometimes referred to as the stop end of the runway.

Takeoff Runway Available (TORA)

The length of runway declared available and suitable 

for the ground run of an airplane takeoff.

Takeoff Distance Available (TODA) 

The length of the takeoff runway available plus 

the length of the clearway, if provided.

Accelerate-Stop Distance Available 

(ASDA) 

The runway plus stopway length 

declared available and suitable for 

the acceleration and deceleration 

of an airplane aborting a takeoff.

Initial Climb Area (ICA) 

The ICA is the segment of the departure procedure that 

starts at the DER and proceeds along the runway 

centerline extended to allow the aircraft sufficient distance 

to reach an altitude of 400 feet above DER elevation and 

to allow the establishment of positive course guidance by 

all navigation systems. A typical straight departure ICA 

extends 2-5 NM from the DER along the runway centerline 

extended. It is 500 feet wide each side of the runway 

centerline at DER, then spreads out at 15°.

Start End of Runway (SER)

The beginning of the takeoff runway available.

Approach End of Runway (AER)

The first portion of the runway available for landing. 

If the runway threshold is displaced, the displaced 

threshold latitude/longitude is the AER.

Landing Distance Available (LDA)

The length of runway that is declared available and 

suitable for the ground run of an airplane landing.

New TERPS Departure Procedures

48 '

35 feet

152 feet

304 feet 96 feet

Required climb

gradient of 200 FPNM 

Obstacle clearance

surface (OCS)

Slope of 152 FPNM or 40:1

Runway

Centerline Extended

Minimum assumed “at or above” 

intended aircraft climb path

Design Criteria

The design of a departure procedure is based on terminal 

instrument procedures (TERPS), which is a living document 

that is updated frequently (FAA Order 8260.3). Departure 

design criterion begins with the assumption of an initial 

climb of 200 FPNM after crossing the DER at a height 

of at least 35 feet. [Figure 1-14] The aircraft climb path 

assumption provides a minimum of 35 feet of additional 

obstacle clearance above the required obstacle clearance 

(ROC), from the DER outward, to absorb variations ranging 

from the distance of the static source to the landing gear, 

to differences in establishing the minimum 200 FPNM climb 

gradient, etc. The ROC is the planned separation between 

the obstacle clearance surface (OCS) and the required climb 

gradient of 200 FPNM. The ROC value is zero at the DER 

elevation and increases along the departure route until 

the ROC value appropriate for en route flight is achieved. 

The appropriate ROC value for en route operations is 

typically achieved about 25 NM for 1,000 feet of ROC in 

non-mountainous areas, and 46 NM for 2,000 feet of ROC 

in mountainous areas.

If taking off from a runway using a diverse departure 

(a runway without a published ODP), beyond these 

distances the pilot is responsible for obstacle clearance if 

not operating on a published route, and if below the MEA 

or MOCA of a published route, or below an ATC-assigned 

altitude. [Figure 1-15] 

Recent changes in TERPS criteria make the OCS lower and 

more restrictive. [Figure 1-16] However, there are many 

departures today that were evaluated under the old criteria 

that allowed some obstacle surfaces to be as high as 35 feet 

at the DER. [Figure 1-14] Since there is no way for the pilot 

to determine whether the departure was evaluated using 

the previous or current criteria, and until all departures 

have been evaluated using the current criteria, pilots need 

to be very familiar with the departure environment and 

associated obstacles, especially if crossing the DER at less 

than 35 feet.

All departure procedures are initially assessed for obstacle 

clearance based on a 40:1 Obstacle Clearance Surface (OCS). 

If no obstacles penetrate this 40:1 OCS, the standard 200
1-17

FPNM climb gradient provides a minimum of 48 FPNM of 

clearance above objects that do not penetrate the slope. 

The departure design must also include the acquisition 

of positive course guidance (PCG), typically within 5 to 10 

NM of the DER for straight departures. Even when aircraft 

performance greatly exceeds the minimum climb gradient, 

the published departure routing must always be flown.

Airports publish the declared distances in the A/FD. These 

include takeoff runway available (TORA), takeoff distance 

available (TODA), accelerate-stop distance available (ASDA), 

and landing distance available (LDA). These distances are

calculated by adding to the full length of paved runway any 

applicable clearway or stop-way and subtracting from that 

sum the sections of the runway unsuitable for satisfying the 

required takeoff run, takeoff, accelerate/stop, or landing 

distance as shown in Figure 1-16.

Optimally, the 40 to 1 slope would work for every departure 

design; however, due to terrain and manmade obstacles, 

it is often necessary to use alternative requirements to 

accomplish a safe, obstacle-free departure design. In 

such cases, the design of the departure may incorporate a 

climb gradient greater than 200 FPNM, an increase in the 

standard takeoff minimums to allow the aircraft to “see and 

avoid” the obstacles, a standard climb of 200 FPNM with a 

specified reduced takeoff length, or a combination of these 

options and a specific departure route.

If a departure route is specified, it must be flown in 

conjunction with the other options.

The obstacle environment may require a climb gradient 

greater than 200 FPNM. In these cases, the ROC provided 

above obstacles is equivalent to 24 percent of the 

published climb gradient. The required climb gradient, 

for obstacle purposes on ODPs and SIDs, is obtained by 

using the formulas:

Standard Formula DoD Option*

CG = O – E CG = (48D + O) – E

 0.76 D D

O = obstacle mean sea level (MSL) elevation

E = climb gradient starting MSL elevation 

D = distance (NM) from DER to the obstacle

Examples:

2049 – 1221 = 351.44 (48 × 3.1 + 2049) – 1221 = 315.10 0.76 × 3.1 3.1

Round to 352 FPNM Round to 316 FPNM

*Military only

These formulas are published in TERPS Volume 4 for 

calculating the required climb gradient to clear obstacles.

The following formula is used for calculating SID climb 

gradients for other than obstacles (i.e., ATC requirements):

 

CG = A – E

 D

A = “climb to” altitude 

E = climb gradient starting MSL elevation 

D = distance (NM) from the beginning of the climb

Example:

3000 – 1221 = 355.8 round to 356 FPNM

 5

NOTE: The climb gradient must be equal to or greater than 

the gradient required for obstacles along the route of flight.

The published climb gradient, obstacle or otherwise, is 

treated as a plane which must not be penetrated from 

above until reaching the stated height or has reached 

the en route environment (e.g., above the MEA, MOCA). 

Departure design, including climb gradients, does not 

take into consideration the performance of the aircraft; it 

only considers obstacle protection for all aircraft. TERPS 

criteria assume the aircraft is operating with all available 

engines and systems fully functioning. Development of 

contingency procedures, required to cover the case of 

an engine failure, engine out procedures (EOPs) or other 

emergency in flight that may occur after liftoff, is the 

responsibility of the operator. When a climb gradient is 

required for a specific departure, it is vital that pilots fully 

understand the performance of their aircraft and determine 

if it can comply with the required climb. The standard 

climb of 200 FPNM is not an issue for most aircraft. When 

an increased climb gradient is specified due to obstacle 

issues, it is important to calculate aircraft performance, 

particularly when flying out of airports at higher altitudes 

on warm days. To aid in the calculations, the front matter 

of every TPP booklet contains a rate of climb table that 

relates specific climb gradients and typical groundspeeds 

[Figure 1-17].

Low, Close-In Obstacles

Obstacles that are located within 1 NM of the DER and 

penetrate the 40:1 OCS are referred to as “low, close-in 

obstacles” and are also included in the TPP. These obstacles 

are less than 200 feet above the DER elevation, within 1 NM 

of the runway end, and do not require increased takeoff 

minimums. The standard ROC to clear these obstacles 

would require a climb gradient greater than 200 FPNM 
1-18

Figure 1-17. Rate of climb table.

SAMPLE NOT FOR ACTUAL USE 

Ground speed is 180 knots.

Required climb gradient of 297 FPNM

Given the parameters, you would need to climb at a rate 

of 892 feet per minute to maintain the required climb gradient.

for a very short distance, only until the aircraft was 200 

feet above the DER. To eliminate publishing an excessive 

climb gradient, the obstacle above ground level (AGL)/

MSL height and location relative to the DER is noted in the 

Takeoff Minimums and (Obstacle) Departure Procedures 

section of a given TPP booklet. The purpose of this note 

is to identify the obstacle and alert the pilot to the height 

and location of the obstacle so they can be avoided. This 

can be accomplished in a variety of ways: 

•	 The pilot may be able to see the obstruction and

maneuver around the obstacle(s) if necessary; 

•	 Early liftoff/climbperformancemay allowthe aircraft

to cross well above the obstacle(s); 

•	 Ifthe obstacle(s) cannot be visually acquired during

departure, preflight planning should take into account 

what turns or other maneuver(s) may be necessary 

immediately after takeoff to avoid the obstruction(s). 

These obstacles are especially critical to aircraft that do not 

lift off until close to the DER or which climb at the minimum 

rate. [Figure 1-18]

One-Engine-Inoperative (OEI) Takeoff Obstacle 

Clearance Requirements 

Large and turbine-powered, multiengine transport 

category airplanes and commuter category airplanes 
1-19

Figure 1-18. Examples of takeoff minimums obstacle clearance.

YUBBAINTbeforeproceedingoncourse.

NOTE: Rwy 7, trees beginning 1117' from DER, 504'

rightof centerline,upto40'AGL/1708'MSL.Pole1365'

fromDER,600'rightof centerline,59'AGL/1679'MSL.

Tree 3791' from DER, 700'right of centerline, 40'AGL/

1639' MSL. Rwy 25, tree 37' from DER, 479' left of

centerline,40'AGL/1528'MSL.Tree86'fromDER,461'

rightof centerline,40'AGL/1532'MSL.Fence301'from

DER, 244'right of centerline, 8'AGL/1508' MSL.Trees

beginning 660' from DER, 249'right of centerline, up to

40'AGL/1559'MSL.

BEALEAFB(KBAB)

MARYSVILLE, CA. . . . . . . . . .ORIG, 09155

DEPARTUREPROCEDURE:Rwy15,Climbona

Rwy33,

DER.

TAKE-OFFOBSTACLES:Rwy33,

BECKWOURTH,CA

NERVINO

TAKE-OFF MINIMUMS: Rwys 7, 25, 3500-3 for climb in

visualconditions.

DEPARTUREPROCEDURE: Rwys 7, 25, for climb in

visual conditions: crossNervinoAirportatorabove

8300beforeproceedingoncourse.

NOTE: Rwy7,road58'fromdepartureendofrunway,

469'rightof centerline, 15'AGL/4920' MSL. Pole310'

fromdepartureendofrunway,522'rightofcenterline,

49'AGL/4925'MSL. Pole528'fromdepartureendof

proceedingoncourse. Rwy12, climbingleftturnvia

VORTACbeforeproceedingoncourse. Rwy30,

R-250toECAVORTACbeforeproceedingoncourse.

NOTE: Rwy5,bush17'fromdepartureendofrunway,67'

rightof centerline,6'AGL/52'MSL. Rwy 12,multiple

treesandbushbeginning240'fromdepartureendof

runway,286'rightof centerline,upto39'AGL/76'MSL.

Rwy30,multiplepoles,building,andterrainbeginning

66'fromdepartureendofrunway,228' leftofcenterline,

up to 65'AGL/225' MSL. Multiple poles beginning 949'

fromdepartureendofrunway,28'rightofcenterline,up

to42'AGL/103'MSL.

CHICO, CA

CHICO MUNI

DEPARTUREPROCEDURE: Rwys13L/R,climbing

right turn.Rwys31L/R,climbing left turn. Allaircraft,

climb via CIC R-205 to JINGOInt.Aircraft departing

inbound)todepartJINGOIntatorabove2800.

CLOVERDALE, CA

CLOVERDALE MUNI

TAKE-OFF MINIMUMS: Rwy 14, 400-2 or std. with a

min. climb of 280' perNM to 1500, then a min. climb of

260'perNMto3900. Rwy32, NA.

DEPARTUREPROCEDURE: Rwy 14, climb directSTS

VOR/DME. Continue climb in holding pattern (NW

23 SEP 2010 to 21 OCT 2010

23 SEP 2010 to 21 OCT 2010

SAMPLE NOT FOR ACTUAL USE 

L2

TAKE-OFFMINIMUMSAND(OBSTACLE)DEPARTUREPROCEDURES 10266

AUBURN,CA

AUBURN MUNI (AUN)

AMDT 1 10098 (FAA)

TAKE-OFFMINIMUMS:Rwy7,300-1w/min. climbof

385' per NM to 2300, or 1100-3 for climb in visual

conditions.

DEPARTUREPROCEDURE:Rwy7, climbing left turn

MYVVOR/DME, then via MYVVOR/DME R-263 to

YUBBAINTbeforeproceedingoncourse,orfor climb

invisual conditions: crossAuburn Muniairportator

MYVVOR/DME R-094 to MYVVOR/DME, then via

MYVVOR/DME R-263 toYUBBAINT before

proceeding on course. Rwy25, climbingrightturnto

MYVVOR/DME, then via MYVVOR/DME R-263 to

YUBBAINTbeforeproceedingoncourse.

NOTE: Rwy 7, trees beginning 1117' from DER, 504'

rightof centerline,upto40'AGL/1708'MSL.Pole1365'

fromDER,600'rightof centerline,59'AGL/1679'MSL.

Tree 3791' from DER, 700'right of centerline, 40'AGL/

1639' MSL. Rwy 25, tree 37' from DER, 479' left of

centerline,40'AGL/1528'MSL.Tree86'fromDER,461'

BISHOP, CA

EASTERN SIERRA RGNL

TAKE-OFFMINIMUMS:Rwys7,12,16,NA.Rwys25,

30,34, 4000-2 or std.with a min. climb of 350' perNM to

9000.

DEPARTUREPROCEDURE:Rwys25,30,turnright.

Rwy34,turnleft,climbnorthwestboundto13000viaBIH

R-322toNIKOLInt.

BYRON,CA

BYRON

TAKE-OFFMINIMUMS: Rwy23, NA-obstacles.

 Rwy 30, 200-1 or std. with a min. climb of 240' per NM to

300. Alternatively,withstandardtake-offminimumsanda

normal200'/NMclimbgradient,take-offmustoccurno

laterthan2000'priortodepartureendofrunway.

DEPARTUREPROCEDURE: Rwy 5, climbing right turn

proceedingoncourse. Rwy12, climbingleftturnvia

VORTACbeforeproceedingoncourse. Rwy30,

R-250toECAVORTACbeforeproceedingoncourse.

NOTE: Rwy5,bush17'fromdepartureendofrunway,67'

SAMPLE NOT FOR ACTUAL USE 

Figure 1-19. Part 25 turbine-powered, transport category airplane OEI actual (gross) takeoff flight path and OEI net takeoff flight path.

Takeoff distance Takeoff flight path

Acceleration

One engine inoperative

BR V2 VFTO VEF V1 VR VLOF

Climb

1,500 ft

35 ft

35 ft

35 ft

Regulatory 

performance 

reduction

N

Second

segment

Third

segment

Final

segment

First

seg.

operated under Part 121 or Part 135 have additional takeoff 

obstacle clearance requirements beyond the scope of the 

IFR departure procedure requirements addressed by TERPS. 

Part 25 transport category and Part 23 commuter category 

airplane certification rules define the one-engineinoperative (OEI) takeoff flight path, which is normally 

constructed from a series of segments beginning from 35 
1-20

feet above the runway surface at the end of the OEI takeoff 

distance and ending at a minimum height of 1,500 feet 

above the runway elevation. However, the OEI net takeoff 

flight path assessment may continue above 1,500 feet if 

necessary to ensure obstacle clearance.

The actual, or gross, OEI flight path represents the vertical 

OEI climb profile that the airplane has been demonstrated 

capable of achieving using takeoff procedures developed 

for line operations based on the airplane’s weight, 

configuration, and environmental conditions at the time 

of takeoff. The OEI net takeoff flight path represents the 

actual OEI takeoff flight path that has been degraded by 

an amount specified by the certification rules to provide 

a safety margin for expected variations under operational 

conditions. Subpart I of Part 121 and Part 135 require that 

the OEI net takeoff flight path be at least 35 feet above 

obstacles that are located within the prescribed lateral 

distance either side of the flight path The actual obstacle 

clearance capability, under optimum conditions after 

experiencing an engine failure on takeoff, is equal to the 

difference between gross and net flight path, plus the 

additional 35 feet. [Figure 1-19]

Advisory Circular (AC) 120-91, Airport Obstacle Analysis, 

provides guidance and acceptable criteria for use in 

determining the safe lateral clearance from obstacles, when 

developing takeoff and initial climb out airport obstacle 

analyses and engine out obstacle avoidance procedures to 

comply with the intent of these regulatory requirements. 

Pilots departing an airport under IFR and operating under 

Part 121 or 135 are required by 14 CFR 91.175(f )(4) to 

use an engine-inoperative takeoff obstacle clearance 

or avoidance procedure that assures compliance with 

the obstacle clearance requirements (subpart I) of those 

rules. The assessment of OEI takeoff obstacle clearance is 

separate and independent of the IFR departure procedure 

and associated all-engines- operating climb gradient 

requirements. While the Part 91 operating rules governing 

large and turbine-powered airplanes and commuter 

category airplanes do not require the use of an OEI takeoff 

obstacle clearance or avoidance procedure, such use is 

encouraged for Part 91 operators of these airplanes.

Unlike TERPS, which assesses obstacle clearance beginning 

at the DER, the OEI net takeoff flight path obstacle 

assessment begins at the point where the aircraft reaches 

35 feet above the runway at the end of the OEI takeoff 

distance. Therefore, the OEI net takeoff flight path 

assessment may begin before the DER allowing for the 

use of a portion of the runway for the OEI climb. The OEI 

net takeoff flight path obstacle clearance assessment must 

also account for clearance of the low, close-in obstacles 

that are noted on the IFR departure procedure, but are not 

necessarily cleared when complying with the TERPS-based 

IFR climb gradient.

The OEI net takeoff flight path is unique for each airplane 

type and is assessed on each takeoff for the required 

obstacle clearance directly against those obstacles located 

beneath the OEI flight track and within the prescribed 

lateral distance from the flight path centerline. TERPS, on 

the other hand, provides a required climb gradient that 

represents a surface that the aircraft’s all-engines-operating 

climb profile must remain above throughout the IFR 

climb until reaching the en route environment. These two 

methods of assessing obstacle clearance are necessarily 

quite different. TERPS is used by the procedure designer 

to determine a lateral path that is usable by a wide variety 

of aircraft types, and establishes a clearance plane that 

aircraft must be able to stay above to fly the procedure. A 

Part 25 transport category and Part 23 commuter category 

airplane’s OEI takeoff flight path is established by or on 

behalf of the operator for a particular aircraft type and then 

limit weights are determined that assure clearance of any 

obstacles under that flight path (or within the prescribed 

lateral distance from the flight path centerline).

It may be necessary for pilots and operators of these 

categories of airplanes to use the services of an aircraft 

performance engineer or airport/runway analysis service 

provider as means of compliance with the requirements 

of Part 121 subpart I, or Part 135 subpart I concerning 

OEI net takeoff flight obstacle clearance and takeoff field 

length requirements. [Figure 1-20] Airport/runway analysis 

involves the complex, usually computerized, computations 

of aircraft performance, using extensive airport/obstacle 

databases and terrain information. This yields maximum 

allowable takeoff and landing weights for particular 

aircraft/engine configurations for a specific airport, runway, 

and range of temperatures. The computations also consider 

flap settings, various aircraft characteristics, runway 

conditions, obstacle clearance, and weather conditions. 

Obstacle data also is available from these service providers 

for operators who desire to perform their own analysis 

using the OEI climb performance and flight path data 

furnished in the Airplane Flight Manual or when using an 

aircraft electronic performance program supplied by the 

manufacturer or other service provider.

Airport/runway analysis is typically based on the 

assumption that the pilot will fly a straight-out departure 

following an engine failure on takeoff. However, when a 

straight-out departure is not practical or recommended, 

a special OEI turn procedure can be developed for each 
1-21

Figure 1-20. Airport/runway analysis example.

50

52

54

55

57

59

61

63

64

66

68

70

72

73

75

77

79

81

82

84

86

88

90

91

93

95

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

Elevation = 5883 ft

SEC.

SEG.

CLIMB

OAT

RUNWAY DIM

LVLOFF ALT

WIND CORR

QNH

ANTI-ICE

LIMIT CODES

DATE: 07/01/2011 FOR SAMPLE USE ONLY

R = RUNWAY LIMIT O = OBSTACLE LIMIT B = BRAKE LIMIT C = CLIMB LIMIT

F C

N1 10 17L 17R 28 35L 35R A/1

ON

Length = ft

Slope = %

lbs/kt hw

lbs/kt tw

lbs/.1"Hg > 29.92

lbs/.1"Hg < 29.92

ft

lbs

Max Structural Takeoff Weight Limit = 28000

Runways - lbs

98.91

98.73

98.56

98.47

98.29

98.11

97.95

97.80

97.72

97.56

97.40

97.20

97.00

96.90

96.70

96.50

96.24

95.97

95.84

95.58

95.31

95.04

94.77

94.64

94.37

94.10

21880 R

21750 R

21620 R

21550 R

21420 R

21290 R

21160 R

21020 R

20960 R

20820 R

20670 R

20530 R

20380 R

20310 R

20170 R

20020 R

19880 R

19710 R

19630 R

19460 R

19290 R

19130 R

18980 R

18900 R

18740 R

18590 R

4800

–0.62

7383

67

N/A

75

–87

–1210

29380 C

29340 C

29190 C

29100 C

28950 O

28790 O

28620 O

28450 O

28360 O

28170 O

27980 O

27720 O

27460 O

27370 R

27110 R

26860 R

26590 R

26330 R

26190 R

25920 R

25610 R

25300 R

24990 R

24840 R

24530 R

24220 R

10002

0.9

7383

5

–254

10

–127

–1400

25250 R

25070 R

24900 R

24820 R

24650 R

24490 R

24320 R

24160 R

24080 R

23930 R

23770 R

23610 R

23420 O

23340 O

23170 O

22990 O

22810 O

22630 O

22540 O

22320 O

22120 O

21930 O

21730 O

21630 O

21440 O

21240 O

7000

0.93

7383

31

–227

85

–99

–1480

26690 R

26500 R

26310 R

26210 R

26020 R

25830 R

25650 R

25460 R

25370 R

25180 R

25000 R

24810 R

24630 R

24530 R

24350 R

24150 R

23960 R

23760 R

23660 R

23460 R

23260 R

23070 R

22870 R

22770 R

22570 R

22380 R

7000

–0.93

7383

42

–223

88

–113

–1690

29460 C

29460 C

29460 C

29460 C

29460 C

29460 C

29360 C

29210 C

29120 C

28870 R

28630 R

28380 R

28110 R

27970 R

27690 R

27390 R

27100 R

26800 R

26650 R

26350 R

26050 C

25740 C

25440 C

25290 C

24990 C

24690 C

10002

–0.9

7383

4

–131

5

–114

–830

21210 R

21090 R

20950 R

20890 R

20750 R

20620 R

20490 R

20360 R

20300 R

20170 R

20030 R

19880 R

19740 R

19670 R

19530 R

19390 R

19240 R

19070 R

18990 R

18820 R

18650 R

18490 R

0 R

0 R

0 R

0 R

4800

0.62

7383

62

N/A

0

–86

–1180

29000

29000

29000

29000

29000

29000

29000

29000

29000

29000

28930

28630

28330

28180

27870

27570

27230

26890

26720

26380

26040

25690

25350

25180

24830

24490

---

---

---

---

---

0

–123

–70

97.11

Sample Aircraft

Engine Type

Flaps 0

KAPA/APA

Denver - Centennial

Runway Conditions: Dry
1-22

Figure 1-21. Graphic ODP/booklet front matter.

L9

TAKE-OFFMINIMUMSAND(OBSTACLE)DEPARTUREPROCEDURES 10266

PUEBLO,CO

PUEBLO MEMORIAL (PUB)

AMDT 4 09295 (FAA)

TAKE-OFFMINIMUMS: Rwy 35,300-1 or standardw/

DEPARTUREPROCEDURE: Rwy 8L, climbheading

PUB R-040 toPUBVORTAC, continue climb inPUB

inbound)to crossPUBVORTACat or above MEAfor

routeofflight. Rwy8R,

PUBVORTAC, continue climb inPUBVORTAC

crossPUBVORTAC at or above MEAforroute of flight.

Rwy17,

turnviaheading050andPUBR-180toPUBVORTAC,

continueclimbinPUBVORTACholdingpattern(hold

atoraboveMEAforrouteofflight. Rwy 26L, climb

inPUBVORTAC holding pattern (hold NE,right turns,

forrouteofflight. Rwy26R,

toPUBVORTAC, continue climb inPUBVORTAC

crossPUBVORTAC at or above MEAforroute of flight.

Rwy35,

continueclimbinPUBVORTACholdingpattern(hold

at or above MEAforroute of flight.

NOTE: Rwy 8L,rising terrain 57' from DER, 123' left of

centerline, upto4649' MSL.Rwy8R,rising terrain180'

from DER, 58' leftof centerline, up to 4659' MSL.

 Rwy 26L, rising terrain 110' from DER, 182' right of

centerline, up to 4659' MSL,rising terrain 128' from

DER,122' leftof centerline,upto4659'MSL.Rwy26R,

rising terrain 208' from DER, 446' right of centerline, up

to 4679' MSL. Rwy 35,

of centerline, up to 4749' MSL,rising terrain 196' from

DER, 11'right of centerline, up to 4793' MSL,

RIFLE,CO

GARFIELD COUNTY RGNL (RIL)

AMDT 8 08157

TAKE-OFF MINIMUMS: Rwy 8, std.w/ a min. climb of

369' perNM to 12400 or 5400-3 for climb in visual

conditions.

DEPARTUREPROCEDURE: Rwy 8,DMErequired.

Climb viaRILR-081 toZOBAK/10DME,then climbing

left turn direct RIL VOR/DME. Climb in RIL VOR/DME

crossRILVOR/DMEat or above MEA/MCAbefore

proceedingen route,orfor climbinvisual conditions

crossGarfieldCountyRgnlAirportatorabove10800

beforeproceedingoncourse. Rwy26,useSQUAT

RNAV DEPARTURE.

NOTE: Rwy8,transmission line towersbeginning1.2NM

fromdepartureendofrunway,437'rightofcenterline,up

to 150'AGL/6069' MSL. Trees beginning 1.9 NM from

departureendofrunway,647'rightofcenterline,upto

100'AGL/5983'MSL. Terrainbeginning124'from

departureendofrunway,287'rightofcenterline,upto

5863'MSL. Pole1083'fromdepartureendofrunway,

656'rightof centerline,28'AGL/5588'MSL.

ROSWELL, NM

ROSWELL INTL AIR CENTER

DEPARTUREPROCEDURE:Rwy30, climbto6000via

runwayheadingtointerceptCMER-323,uponreaching

6000proceedoncourse. Rwy35, climbingleftturnto

reaching6000proceedoncourse.

RUIDOSO,NM

SIERRA BLANCA RGNL

TAKE-OFFMINIMUMS:Rwys6,24,5200-3or std.witha

min. climb of 420' perNM to 12,100'.

DEPARTUREPROCEDURE:Rwy6, climb at385' per

NM to 9100' direct CEP NDB, continue climb in holding

NDBat or above the MEAfor direction of flight. *Do not

exceed230ktsinholdingpattern.Rwy24,immediate

climbing left turn to 9100' directCEPNDB, continue

23 SEP 2010 ot 21 OCT 2010

23 SEP 2010 to 21 OCT 2010

SAMPLE NOT FOR ACTUAL USE 

NOT FOR NAVIGATION

Denotes either takeoff minimums or an obstacle departure procedure published in the front of the TPP.

Obstacle departure procedure

applicable runway. This OEI turn procedure may follow 

the path of a published IFR departure procedure or it may 

follow an independent path designed to avoid otherwise 

onerous obstacles and thereby maximize the allowable 

takeoff weight and payload. Graphic depiction of the OEI 

procedure is often available to give the pilot a pictorial 

representation of the special OEI procedure. An engine 

failure during takeoff is a non-normal condition, and 

therefore the actions taken by the pilot including the use 

of an OEI turn procedure takes precedence over noise 

abatement, air traffic, SIDs, DPs, and other normal operating 

considerations.

It must be understood that the airport/runway analysis 

assesses obstacle clearance using the OEI net takeoff flight 

path data provided in the Airplane Flight Manual and the 

selected lateral obstacle assessment area. A takeoff weight 

limit provided on the analysis does not necessarily ensure 

compliance with the all-engines-operating climb gradient 

published on an IFR departure procedure even if the 

track of the OEI special procedure and the IFR departure 

procedure are identical.

Categories of Departure Procedures

There are two types of DPs: those developed to assist 

pilots in obstruction avoidance, known as ODPs, printed 

either textually or graphically, and those developed 

to communicate ATC clearances, SIDs, always printed 

graphically.

Obstacle Departure Procedures (ODPs)

The term ODP is used to define procedures that simply 

provide obstacle clearance. ODPs are only used for 

obstruction clearance and do not include ATC related 

climb requirements. In fact, the primary emphasis of ODP 

design is to use the least restrictive route of flight to the 

en route structure or to facilitate a climb to an altitude 

that allows random (diverse) IFR flight, while attempting 

to accommodate typical departure routes.
1-23

An ODP must be developed when obstructions penetrate 

the 40:1 departure OCS, as described in Order 8260.3, 

Volume 4 TERPS. Only one ODP will be established for 

a particular runway. This is considered the default IFR 

departure procedure for a given runway and is intended 

for pilot awareness and use in the absence of ATC radar 

vectors or SID assignment. Text is not published to allow 

an option to use a SID or alternate maneuver assigned by 

ATC (e.g., “Climb runway heading to 1200 before turning 

or use Manchester Departure” or “Turn right, climb direct 

ABC very high frequency (VHF) omnidirectional range 

(VOR) or as assigned by ATC.”). ODPs are textual in nature. 

However, due to the complex nature of some procedures, 

a visual presentation may be necessary for clarification and 

understanding. If the ODP is charted graphically, the chart 

itself includes the word “Obstacle” in parentheses in the title. 

Additionally, all newly-developed RNAV ODPs are issued in 

graphical form.

All ODPs are listed in the front of the AeroNav Products 

approach chart booklets under the heading Takeoff 

Minimums and Obstacle Departure Procedures. Each 

procedure is listed in alphabetical order by city and state. 

The ODP listing in the front of the booklet includes a 

reference to the graphic chart located in the main body of 

the booklet if one exists. [Figure 1-21]

ODP Flight Planning Considerations

ODPs are not assigned by ATC unless absolutely necessary 

to achieve aircraft separation. It is the pilot’s responsibility 

to determine if there is an ODP published for that airport. If a 

Part 91 pilot is not given a clearance containing an ODP, SID, 

or radar vectors and an ODP exists, compliance with such 

a procedure is the pilot’s choice. A graphic ODP may also 

be filed in an instrument flight plan by using the computer 

code included in the procedure title. As a technique, the 

pilot may enter “will depart (airport) (runway) via textual 

ODP” in the remarks section of the flight plan. Providing 

this information to the controller clarifies the intentions 

of the pilot and helps prevent a potential pilot/controller 

misunderstanding. If the ODP is not included in the pilot’s 

clearance, the pilot should inform ATC when an ODP is 

used for departure from a runway so that ATC can ensure 

appropriate traffic separation.

During planning, pilots need to determine whether or 

not the departure airport has an ODP. Remember, an ODP 

can only be established at an airport that has instrument 

approach procedures (IAPs). An ODP may drastically affect 

the initial part of the flight plan. Pilots may have to depart 

at a higher than normal climb rate, or depart in a direction 

opposite the intended heading and maintain that for a 

period of time, any of which would require an alteration in 

the flight plan and initial headings. Considering the forecast 

weather, departure runways, and existing ODP, plan the 

flight route, climb performance, and fuel burn accordingly 

to compensate for the departure procedure.

Additionally, when close-in obstacles are noted in the 

Takeoff Minimums and (Obstacle) Departure Procedures 

section, it may require the pilot to take action to avoid these 

obstacles. Consideration must be given to decreased climb 

performance from an inoperative engine or to the amount 

of runway used for takeoff. Aircraft requiring a short takeoff 

roll on a long runway may have little concern. On the other 

hand, airplanes that use most of the available runway for 

takeoff may not have the standard ROC when climbing at 

the normal 200 FPNM.

Another factor to consider is the possibility of an 

engine failure during takeoff and departure. During the 

preflight planning, use the aircraft performance charts 

to determine if the aircraft can still maintain the required 

climb performance. For high performance aircraft, an 

engine failure may not impact the ability to maintain the 

prescribed climb gradients. Aircraft that are performance 

limited may have diminished capability and may be unable 

to maintain altitude, let alone complete a climb to altitude. 

Based on the performance expectations for the aircraft, 

construct an emergency plan of action that includes 

emergency checklists and the actions to take to ensure 

safety in this situation.

Standard Instrument Departures (SIDs)

A SID is an ATC-requested and developed departure route, 

typically used in busy terminal areas. It is designed at the 

request of ATC in order to increase capacity of terminal 

airspace, effectively control the flow of traffic with minimal 

communication, and reduce environmental impact 

through noise abatement procedures.

While obstacle protection is always considered in SID 

routing, the primary goal is to reduce ATC/pilot workload 

while providing seamless transitions to the en route 

structure. ATC clearance must be received prior to flying 

a SID. SIDs also provide additional benefits to both the 

airspace capacity and the airspace users by reducing 

radio congestion, allowing more efficient airspace use, 

and simplifying departure clearances. All of the benefits 

combine to provide effective, efficient terminal operations, 

thereby increasing the overall capacity of the NAS.

If you cannot comply with a SID, if you do not possess the 

charted SID procedure, or if you simply do not wish to 

use SIDs, include the statement “NO SIDs” in the remarks 

section of your flight plan. Doing so notifies ATC that they 

cannot issue you a clearance containing a SID, but instead 
1-24

Figure 1-22. SID chart.

SC-5, 23 SEP 2010 to 21 OCT 2010

SC-5, 23 SEP 2010 to 21 OCT 2010

SC-5, 23 SEP 2010 to 21 OCT 2010

SC-5, 23 SEP 2010 to 21 OCT 2010 NOT FOR NAVIGATION
1-25

Figure 1-23. Transition routes as depicted on SID.

SC-2, 23 SEP 2010 to 21 OCT 2010

SC-2, 23 SEP 2010 to 21 OCT 2010

SC-2, 23 SEP 2010 to 21 OCT 2010

SC-2, 23 SEP 2010 ot 21 OCT 2010

NOT FOR NAVIGATION

NOT FOR NAVIGATION

Basic departure computer code

Departure code

College Station Transition instructions

End of transition route

End of basic SID and beginning of transition route
1-26

will clear you via your filed route to the extent possible, 

or via a Preferential Departure Route (PDR). It should be 

noted that SID usage not only decreases clearance delivery 

time, but also greatly simplifies your departure, easing you 

into the IFR structure at a desirable location and decreases 

your flight management load. While you are not required 

to depart using a SID, it may be more difficult to receive 

an “as filed” clearance when departing busy airports that 

frequently use SID routing.

SIDs are always charted graphically and are located in the 

TPP after the last approach chart for an airport. The SID 

may be one or two pages in length, depending on the size 

of the graphic and the amount of space required for the 

departure description. Each chart depicts the departure 

route, navigational fixes, transition routes, and required 

altitudes. The departure description outlines the particular 

procedure for each runway. [Figure 1-22]

Transition Routes

Charted transition routes allow pilots to transition from the 

end of the basic SID to a location in the en route structure. 

Typically, transition routes fan out in various directions 

from the end of the basic SID to allow pilots to choose 

the transition route that takes them in the direction of 

intended departure. A transition route includes a course, 

a minimum altitude, and distances between fixes on the 

route. When filing a SID for a specific transition route, 

include the transition in the flight plan, using the correct 

departure and transition code. ATC also assigns transition 

routes as a means of putting the flight on course to the 

destination. In any case, the pilot must receive an ATC 

clearance for the departure and the associated transition, 

and the clearance from ATC will include both the departure 

name and transition (e.g., Joe Pool Nine Departure, College 

Station Transition). [Figure 1-23]

The SID is designed to allow the pilot to provide his or 

her own navigation with minimal radio communication. 

This type of procedure usually contains an initial set of 

departure instructions followed by one or more transition 

routes. A SID may include an initial segment requiring 

radar vectors to help the flight join the procedure, but the 

majority of the navigation remains the pilot’s responsibility. 

[Figure 1-24]

A radar SID usually requires ATC to provide radar vectors 

from just after takeoff (ROC is based on a climb to 400 feet 

above the DER elevation before making the initial turn) 

until reaching the assigned route or a fix depicted on the 

SID chart. Radar SIDs do not include departure routes or 

transition routes because independent pilot navigation 

is not involved. The procedure sets forth an initial set of 

departure instructions that typically include an initial 

heading and altitude. ATC must have radar contact with 

the aircraft to be able to provide vectors. ATC expects 

you to immediately comply with radar vectors, and they 

expect you to notify them if you are unable to fulfill their 

request. ATC also expects you to make contact immediately 

if an instruction causes you to compromise safety due to 

obstructions or traffic.

It is prudent to review radar SID charts prior to use because 

this type of procedure often includes nonstandard 

lost communication procedures. If you were to lose 

radio contact while being vectored by ATC, you would 

be expected to comply with the lost communication 

procedure as outlined on the chart, not necessarily those 

procedures outlined in the AIM. [Figure 1-25]

SID Flight Planning Considerations

Take into consideration the departure paths included in 

the SIDs, and determine if you can use a standardized 

departure procedure. You have the opportunity to choose 

the SID that best suits your flight plan. During the flight 

planning phase, you can investigate each departure, 

and determine which procedure allows you to depart 

the airport in the direction of your intended flight. Also 

consider how a climb gradient to a specific altitude affects 

the climb time and fuel burn portions of the flight plan. 

Notes giving procedural requirements are listed on the 

graphic portion of a departure procedure, and they are 

mandatory in nature. [Figure 1-26] Mandatory procedural 

notes may include:

•	 Aircraft equipment requirements (DME, ADF, etc.)

•	 ATC equipment in operation (radar)

•	 Minimum climb requirements

•	 Restrictionsforspecifictypesofaircraft(turbojetonly)

•	 Limited use to certain destinations

Cautionary statements may also be included on the 

procedure to notify you of specific activity, but these are 

strictly advisory. [Figure 1-26] If you are unable to comply 

with a specific requirement, you must not file the procedure 

as part of your flight plan. If ATC assigns you a SID, you may 

need to quickly recalculate your all-engines-operating 

performance numbers. If you cannot comply with the 

climb gradient in the SID, you should not accept a clearance 

for that SID and furthermore, you must not accept the 

procedure if ATC assigns it.
1-27

Figure 1-24. Example of a common SID at Denver, Colorado.

SW-1, 23 SEP 2010 to 21 OCT 2010

SW-1, 23 SEP 2010 to 21 OCT 2010

0102NOT FOR NAVIGATION TCO12 ot 0102 PES 32, 1- WS

SW-1, 23 SEP 2010 to 21 OCT 2010

NOT FOR NAVIGATION

Initial departure instructions

Specific lost communications 

procedure for this departure

Transition route instructions

Communication frequencies

Procedure name

Procedure computer code

Routing information including direction, 

altitude, and distance to the next fix.

City and state location and airport name
1-28

Figure 1-25. Example of a radar SID at Denver, Colorado.

SW-1, 23 SEP 2010 ot 21 OCT 2010

SW-1, 23 SEP 2010 to 21 OCT 2010

0102 TCO12 ot 0102 PES 32, 1- WS

SW-1, 23 SEP 2010 to 21 OCT 2010

NOT FOR NAVIGATION En route chart reference

Lost communications procedure 

specific to this departure

Initial departure instructions

Departure airport

required for the procedure. 

•	 Possession of the charted SID procedure.

•	 Personal understanding of the SID in its entirety.

When you accept a clearance to depart using a SID or 

radar vectors, ATC is responsible for traffic separation. 

When departing with a SID, ATC expects you to fly the 

procedure as charted because the procedure design 

considers obstacle clearance. It is also expected that you 

will remain vigilant in scanning for traffic when departing 

in visual conditions. Furthermore, it is your responsibility 

ATC can assign SIDs or radar vectors as necessary for traffic 

management and convenience. To fly a SID, you must 

receive approval to do so in a clearance. In order to accept 

a clearance that includes a SID, you must have the charted 

SID procedure in your possession at the time of departure. 

It is your responsibility as pilot in command to accept or 

reject the issuance of a SID by ATC. You must accept or 

reject the clearance based on:

•	 The ability tocomplywiththe requiredperformance.

•	 The ability to navigate to the degree of accuracy
1-29

Figure 1-26. Departure procedure notes and cautionary statements.

SE-3, 23 SEP 2010 to 21 OCT 2010

SE-3, 23 SEP 2010 to 21 OCT 2010

NOT FOR NAVIGATION

SW-4, 23 SEP 2010 to 21 OCT 2010

SW-4, 23 SEP 2010 to 21 OCT 2010

NOT FOR NAVIGATION SW-4, 23 SEP 2010 to 21 OCT 2

23 SEP 2010 to 21 OCT 2010

NOT FOR NAVIGATION

CAUTION:

intensive

glider activity

to notify ATC if your clearance would endanger your safety 

or the safety of others.

DPs are also categorized by equipment requirements 

as follows:

• 	 Non-RNAV DP—established for aircraft equipped

with conventional avionics using ground-based 

NAVAIDs. These DPs may also be designed using dead 

reckoning navigation. Some flight management 

systems (FMS) are certified to fly a non-RNAV DP 

if the FMS unit accepts inputs from conventional 

avionics sources, such as DME, VOR, and localizer 

(LOC). These inputs include radio tuning and may 

be applied to a navigation solution one at a time or 

in combination. Some FMS provide for the detection 

and isolation of faulty navigation information.

• 	 RNAV DP—established for aircraft equipped with
1-30

Figure 1-27. RNP departure levels.

1.0 NM 1.0 NM

2.0 NM 2.0 NM

Path centerline

RNAV avionics (e.g., GPS, VOR/DME, DME/DME). 

Automated vertical navigation is not required, 

and all RNAV procedures not requiring GPS must 

be annotated with the note: “RADAR REQUIRED.” 

Prior to using TSO-C129 GPS equipment for RNAV 

departures, approach receiver autonomous integrity 

monitoring (RAIM) availability should be checked for 

that location.

• 	 Radar DP—radar may be used for navigation

guidance for SID design. Radar SIDs are established 

when ATC has a need to vector aircraft on departure 

to a particular ATS Route, NAVAID, or fix. A fix may 

be a ground-based NAVAID, a waypoint, or defined 

by reference to one or more radio NAVAIDs. Not all 

fixes are waypoints since a fix could be a VOR or VOR/ 

DME, but all waypoints are fixes. Radar vectors may 

also be used to join conventional or RNAV navigation 

SIDs. SIDs requiring radar vectors must be annotated 

“RADAR REQUIRED.”

Area Navigation (RNAV) Departures

Historically, departure procedures were built around 

existing ground-based technology and were typically 

designed to accommodate lower traffic volumes. Often, 

departure and arrival routes use the same NAVAIDs creating 

interdependent, capacity diminishing routes. RNAV is a 

method of navigation that permits aircraft operation on 

any desired flight path within the coverage of ground- or 

spaced- based NAVAIDs or within the limits of the capability 

of self-contained aids or a combination of these. In the 

future, there will be an increased dependence on the 

use of RNAV in lieu of routes defined by ground-based 

NAVAIDs. As a part of the evolving RNAV structure, the 

FAA has developed departure procedures for pilots flying 

aircraft equipped with some type of RNAV technology. 

RNAV allows for the creation of new departure routes 

that are independent of present fixes and NAVAIDs. RNAV 

routing is part of the National Airspace Redesign (NAR)and 

is expected to reduce complexity and increase efficiency 

of terminal airspace. 

When new RNAV departure procedures are designed, 

they will require minimal vectoring and communications 

between pilots and ATC. Usually, each departure procedure 

includes position, time, and altitude, which increase 

the ability to predict what the pilot will actually do. 

RNAV departure procedures have the ability to increase 

the capacity of terminal airspace by increasing ontime departures, airspace utilization, and improved 

predictability.

All public RNAV SIDs and graphic ODPs are RNAV 1. These 

procedures generally start with an initial RNAV or heading 

leg near the departure end runway. In addition, these 

procedures require system performance currently met 

by GPS, DME/DME/Inertial Reference Unit (IRU) RNAV 

systems that satisfy the criteria discussed in AC 90-100, U.S. 

Terminal and En Route Area Navigation (RNAV) Operations. 

RNAV departures are identifiable by the inclusion of the 

term RNAV in the title of the departure. From a required 

navigation performance (RNP) standpoint, RNAV departure 
1-31

Figure 1-28. Flight plan equipment codes (continued on next page).

A

B

C

D

E1

E2

E3

F

G

H

I

J1

J2

J3

J4

J5

J6

J7

K

L

M1

M2

M3

O

P1 - P9

R

T

U

V

W

X

Y

Z

GBAS landing system

LPV (APV with SBAS)

LORAN C

DME

FMC WPR ACARS

D-FIS ACARS

PDC ACARS

ADF

GNSS (See Note 2)

HF RTF

Intertial Navigation

CPDLC ATN VDL Mode 2 (See Note 3)

CPDLC FANS 1/A HFDL

CPDLC FANS 1/A VDL Mode 4

CPDLC FANS 1/A VDL Mode 2

CPDLC FANS 1/A SATCOM (INMARSAT)

CPDLC FANS 1/A SATCOM (MTSAT)

CPDLC FANS 1/A SATCOM (Iridium)

MLS

ILS

OmegaATC RTF SATCOM

ATC RTF (MTSAT)

ATC RTF (Iridium)

VOR

Reserved for RCP

PBN approved (see Note 4)

TACAN 

UHF RTF 

VHF RTF 

RVSM approved

MNPS approved 

VHF with 8.33 kHz channel spacing capability

Other equipment carried or other capabilities 

(see Note 5)

ICAO Flight Plan Equipment Codes

Suffix 

/X 

/T 

/U 

/D 

/B 

/A 

/M 

/N 

/P 

/Y 

/C

/I 

/E 

/F 

/G 

/R 

/J

/K

/L

/Q 

/W 

Equipment Capability

NO DME

No transponder 

Transponder with no Mode C 

Transponder with Mode C 

DME

No transponder 

Transponder with no Mode C 

Transponder with Mode C 

TACAN ONLY

No transponder 

Transponder with no Mode C 

Transponder with Mode C 

AREA NAVIGATION (RNAV)

LORAN, VOR/DME, or INS with no transponder 

LORAN, VOR/DME, or INS, transponder with no 

Mode C 

LORAN, VOR/DME, or INS, transponder with 

Mode C 

ADVANCED RNAV WITH TRANSPONDER AND 

MODE C (If an aircraft is unable to operate with a 

transponder and/or Mode C, it will revert to the 

appropriate code listed above under Area 

Navigation.)

Flight Management System (FMS) with DME/DME 

and IRU position updating

Flight Management System (FMS) with DME/DME 

position updating

Global Navigation Satellite System (GNSS), 

including GPS or WAAS, with en route and 

terminal capability. 

Required Navigational Performance (RNP). The 

aircraft meets the RNP type prescribed for the 

route segment(s), route(s), and/or area concerned.

Reduced Vertical Separation Minimum (RVSM). 

Prior to conducting RVSM operations within the 

U.S., the operator must obtain authorization from 

the FAA or from the responsible authority, as 

appropriate.

/E with RVSM 

/F with RVSM 

/G with RVSM 

/R with RVSM 

RVSM

FAA Flight Plan Aircraft Suffixes

Effective September 1, 2005

Radio communication, navigation and approach 

aid equipment and capabilities

“N” if no COM/NAV/approach aid equipment for the route to be 

flown is carried, or the equipment is unserviceable, OR “S” if 

standard COM/NAV/ approach aid equipment for the route to be 

flown is carried and serviceable (see Note 1), AND/OR INSERT 

one or more of the following letters to indicate the serviceable 

COM/NAV/approach aid equipment and capabilities available:

Any alphanumeric characters not indicated above are reserved.
1-32

Transponder - Mode A (4 digits - 4,096 codes)

Transponder - Mode A (4 digits - 4,096 codes) and 

Mode C

Transponder—Mode S, including aircraft identication, 

pressure-altitude and extended squitter (ADS-B) 

capability

Transponder—Mode S, including aircraft identication, 

pressure-altitude and enhanced surveillance capability

Transponder—Mode S, including aircraft identication, 

but no pressure-altitude capability

Transponder—Mode S, including aircraft identication, 

pressure-altitude, extended squitter (ADS-B) and 

enhanced surveillance capability

Transponder—Mode S, including pressure-altitude, but 

no aircraft identication capability

Transponder—Mode S, including both pressure altitude 

and aircraft identication capability

Transponder — Mode S with neither aircraft 

identication nor pressure-altitude capability

ADS-B with dedicated 1090 MHz ADS-B “out” capability

ADS-B with dedicated 1090 MHz ADS-B “out” and “in” 

capability

ADS-B “out” capability using UAT

ADS-B “out” and “in” capability using UAT

ADS-B “out” capability using VDL Mode 4

ADS-B “out” and “in” capability using VDL Mode 4

ICAO Flight Plan Equipment Codes

Surveillance equipment and capabilities

SSR Modes A and C

SSR Modes S

ADS-B

INSERT N if no surveillance equipment for the route to be own 

is carried, or the equipment is unserviceable, OR INSERT one or 

more of the following descriptors, to a maximum of 20 characters, 

to describe the serviceable surveillance equipment carriedand/or 

capabilities on board:

Note: Enhanced surveillance capability is the ability of the aircraft 

to down-link aircraft derived data via a Mode S transponder.

A

C

E

H

I

L

P

S

X

B1

B2

U1

U2

V1

V2

Note 1

Note 2

Note 3

Note 4

Note 5

Note 6

Note 7

Note 8

Note 9

Note 10

Note 11

If the letter S is used, standard equipment is considered

to be VHF RTF, VOR and ILS, unless another combination is prescribed by the appropriate ATS authority.

If the letter G is used, the types of external GNSS 

augmentation, if any, are specied in Item 18 following

the indicator NAV/ and separated by a space.

See RTCA/EUROCAE Interoperability Requirements

Standard For ATN Baseline 1 (ATN B1 INTEROP Standard

DO-280B/ED-110B) for data link services air trac

control clearance and information/air trac control

communications management/air trac control

microphone check.

Information on navigation capability is provided to 

ATC for clearance and routing purposes.

If the letter Z is used, specify in Item 18 the other 

equipment carried or other capabilities, preceded 

by COM/, NAV/ and/or DAT, as appropriate.

If the letter R is used, the performance based navigation levels that can be met are specied in Item 18

following the indicator PBN/. Guidance material on the

application of performance based navigation to a

specic route segment, route or area is contained in

the Performance-Based Navigation Manual (Doc 9613).

RNAV equipped aircraft capable of ying RNAV SIDs,

putting “NO SID” in the remarks section will not always

result in a clearance via a Preferential Departure Route

(PDR). The Pilot/Dispatcher must amend Field 18 NAV

from D1 to D0 and remove PBRN RNAV1 Code (D1-D4).

If a RNAV DP is led, an ICAO ight plan must be used.

In Field 18, Pilots/Dispatchers must le a D1 or D2

depending on the RNAV DP. Additionally, Field 18

should include PBN/D1-D4 depending on the navigation update source. See AIM/PANS ATM 4444 for ICAO

ling procedures.

RNAV Q-routes require en route RNAV 2, corresponding

NAV/E2 code and PBN/C1-C4 based on navigation 

system update source.

If an aircraft does not meet the requirements for RVSM,

then the W led in ICAO ight plan Field 10A must be

removed and STS/NONRVSM must be annotated in

Field 18.

Filing requirements for RNAV STARS. Field 18 of the

ICAO ight plan must have a NAV/A1 or A2 assigned to

the RNAV STAR. Additionally, PBN/D1-D4 for RNAV1 or

C1-C4 for RNAV2 should be led. If unable to accept the

RNAV STAR, the ight plan must be amended to change

the NAV/A1 or A2 to A0.

D1 ADS-C with FANS 1/A capabilities

G1 ADS-C with ATN capabilities

Alphanumeric characters not indicated above are reserved.

Example: ADE3RV/HB2U2V2G1

Note: Additional surveillance application should be listed in 

Item 18 following the indicator SUR/ .

D1

G1

NOTE

Figure 1-28. Flight plan equipment codes (continued).
1-33

routes are designed with 1 or 2 NM performance standards 

as listed below. This means you as the pilot and your aircraft 

equipment must be able to maintain the aircraft within 1 

or 2 NM either side of route centerline. [Figure 1-27]

•	 RNAV 1 procedures require that the aircraft’s total

system error remain bounded by ±1 NM for 95 

percent of the total flight time. 

•	 RNAV2 requires a totalsystemerror ofnotmore than

2 NM for 95 percent of the total flight time.

RNP is RNAV with on-board monitoring and alerting; RNP is 

also a statement of navigation performance necessary for 

operation within defined airspace. RNP-1 (in-lieu-of RNAV1) is used when a DP that contains a constant radius to a 

fix (RF) leg or when surveillance (radar) monitoring is not 

desired for when DME/DME/IRU is used. These procedures 

are annotated with a standard note: “RNP-1.”

If unable to comply with the requirements of an RNAV 

or RNP procedure, pilots need to advise ATC as soon as 

possible. For example, “N1234, failure of GPS system, 

unable RNAV, request amended clearance.” Pilots are not 

authorized to fly a published RNAV or RNP procedure unless 

it is retrievable by the procedure name from the navigation 

database and conforms to the charted procedure. No other 

modification of database waypoints or creation of userdefined waypoints on published RNAV or RNP procedures 

is permitted, except to change altitude and/or airspeed 

waypoint constraints to comply with an ATC clearance/

instruction, or to insert a waypoint along the published 

route to assist in complying with an ATC instruction. For 

example, “Climb via the WILIT departure except cross 30 

north of CHUCK at/ or above FL 210.” This is limited only 

to systems that allow along track waypoint construction.

Pilots of aircraft utilizing DME/DME for primary navigation 

updating should ensure any required DME stations are in 

service as determined by NOTAM, ATIS, or ATC advisory. 

DME/DME navigation system updating may require specific 

DME facilities to meet performance standards. Based on 

DME availability evaluations at the time of publication, 

current DME coverage is not sufficient to support DME/DME 

RNAV operations everywhere without IRU augmentation or 

use of GPS. [Figure 1-28] DP chart notes may also include 

operational information for certain types of equipment, 

systems, and performance requirements, in addition to 

the type of RNAV departure procedure.

While operating on RNAV segments, pilots are encouraged 

to use the flight director in lateral navigation mode. RNAV 

terminal procedures may be amended by ATC issuing radar 

vectors and/or clearances direct to a waypoint. Pilots should 

avoid premature manual deletion of waypoints from their 

active “legs” page to allow for rejoining procedures. While 

operating on RNAV segments, pilots operating /R aircraft 

should adhere to any flight manual limitation or operating 

procedure required to maintain the RNP value specified for 

the procedure. In 2008, the FAA implemented the use of 

en route host automation ICAO flight plan (FP) processing 

for requesting assignment of RNAV SID, Standard Terminal

Arrivals (STARs), or RNAV routes U.S. domestic airspace. 

This is part of a risk reduction strategy for introduction of 

the En Route Automation Modernization (ERAM) system in 

October 2008. ERAM also will use ICAO FP processing and as 

a result aircrews should be aware that as the FAA updates to 

ERAM the standard FAA flight plan equipment suffix codes 

will change to the ICAO flight plan equipment suffix codes.

For procedures requiring GPS and/or aircraft approvals 

requiring GPS, if the navigation system does not 

automatically alert the flight crew of a loss of GPS, aircraft 

operators must develop procedures to verify correct GPS 

operation. If not equipped with GPS, or for multi-sensor 

systems with GPS that do not alert upon loss of GPS, aircraft 

must be capable of navigation system updating using DME/

DME or DME/DME/ IRU for type 1 and 2 procedures. AC 90-

100 may be used as operational guidance for RNAV ODPs. 

Pilots of FMS- equipped aircraft who are assigned an RNAV 

DP procedure and subsequently receive a change of runway, 

transition, or procedure, must verify that the appropriate 

changes are loaded and available for navigation.[Figures 

1-29 and 1-30]

Additionally, new waypoint symbols are used in conjunction 

with RNAV charts. There are two types of waypoints 

currently in use: fly-by (FB) and fly-over (FO). A FB waypoint 

typically is used in a position at which a change in the course 

of procedure occurs. Charts represent them with fourpointed stars. This type of waypoint is designed to allow 

you to anticipate and begin your turn prior to reaching the 

waypoint, thus providing smoother transitions. Conversely, 

RNAV charts show a FO waypoint as a four-pointed star 

enclosed in a circle. This type of waypoint is used to denote 

a missed approach point, a missed approach holding 

point, or other specific points in space that must be flown 

over. [Figure 1-31] Pilots should not change any database 

waypoint type from a FB to FO, or vice versa.

There are specific requirements, however, that must be met 

before using RNAV procedures. Every RNAV departure chart 

lists general notes and may include specific equipment and 

performance requirements, as well as the type of RNAV 

departure procedure in the chart plan view. New aircraft 

equipment suffix codes are used to denote capabilities for 

advanced RNAV navigation for flight plan filing purposes. 

[Figure 1-32]
1-34

Figure 1-29. Examples of RNAV SID.

SW-4, 23 SEP 2010 to 21 OCT 2010

0102 TCO12 ot 0102 PES 32, 4- WS

0102 TCO12 ot 0102 PES 32, 4- WS

SW-4, 23 SEP 2010 to 21 OCT 2010

NOT FOR NAVIGATION

NOT FOR NAVIGATION

Initial departure descriptions from various runways to COWBY waypoint Transition route codes

General notes

Minimum en route altitude (MEA) 

and minimum obstacle clearance 

altitude (MOCA)

Denotes RNAV 

departure

Departure route heading and distance between waypoint

Fly-by (FB) waypoint

Minimum altitude restriction

Secondary departure instructions from COWBY waypoint
1-35

Figure 1-30. Examples of RNAV ODP.

SW-2, 23 SEP 2010 to 21 O

CT 2010

SW-2, 23 SEP 2010 to 21 O

CT 2010

L12

L12

TAKE-OFFMINIMUMSAND(OBSTACLE)DEPARTUREPROCEDURES

TAKE-OFFMINIMUMSAND(OBSTACLE)DEPARTUREPROCEDURES

SW-2

10266

10266

TRAVIS AFB (KSUU)

FAIRFIELD, CA. . . . . . . . . . . . . . 10070

AllRwy: ComplywithassignedSIDorATCradar vectors.

TAKE-OFFOBSTACLES:Rwy3L,

rightof centerline.Rwy21L,

DEPARTUREPROCEDURE:Rwy3L,Climb on a

Rwy3R,

DER.

TRUCKEE,CA

TRUCKEE-TAHOE(TRK)

AMDT 4 08269 (FAA)

TAKE-OFFMINIMUMS:Rwys10,19,NA-obstacles.

DEPARTUREPROCEDURE:Rwys 1,28,useTRUCK

DEPARTURE.

TULARE, CA

MEFFORD FIELD

DEPARTUREPROCEDURE: Rwy 13, climbing right

turn. Rwy31, climbing left turn.Allaircraft climb direct

toVISVOR/DME. Aircraft departingVIS R-001 CW

 R-140 continue climb inVISholding pattern (E,right

4000. All otheraircraft climboncourse.

UKIAH, CA

UKIAH MUNI

TAKE-OFFMINIMUMS:Rwy15,NA.Rwy33,300-1and

min. climb of 350' perNM to 4000.

DEPARTUREPROCEDURE:Climbto4000viaheading

VACAVILLE, CA

NUT TREE (VCB)

AMDT 4 09127 (FAA)

TAKE-OFFMINIMUMS:Rwy20, std.w/min. climbof

424' per NM to 1600, or 1200-2 for climb in visual

conditions.

DEPARTUREPROCEDURE: Rwy 2, climbing right turn

tointerceptSACR-242toSACVORTAC,to2000

beforeproceedingoncourse. Rwy20, climbingleft turn

tointerceptSACR-242toSACVORTAC,to2000

beforeproceedingoncourse,or,for climbinvisual

conditions: crossNutTreeAirporteastboundatorabove

1300,thenclimbto2000viaSACR-242toSAC

VORTAC,proceedoncourse.

NOTE: Rwy 2, trees beginning 222' from DER, 514' left

of centerlineupto106'AGL/225'MSL.Lightpole337'

fromDER,534' leftof centerline,28'AGL/147'MSL.

Rwy20, pole161'fromDER,500' leftof centerline,120'

AGL/239' MSL.Treesbeginning269'fromDER,335'

leftof centerline,upto117'AGL/236'MSL.Pole777'

fromDER,436' leftof centerline,119'AGL/238'MSL.

Windsock 6' from DER, 166'right of centerline, 8'AGL/

127' MSL. Fence 193' from DER, 202'right of

centerline,3'AGL/122'MSL.

VISALIA, CA

VISALIA MUNI (VIS)

AMDT 3 09239 (FAA)

DEPARTUREPROCEDURE: Rwy 12, climbing right

Rwy30,

V23.

NOTE: Rwy 12, tree 774' from DER, 618'right of

centerline,46'AGL/340'MSL.Tree1327'fromDER,

823' leftof centerline,55'AGL/349'MSL. Rwy30,

multiple trees beginning 179' from DER, 260' left of

centerline,upto54'AGL/343'MSL.Antennaonbuilding

285' from DER,250'rightof centerline,16'AGL/305'

MSL.Truckonroad522'fromDER,oncenterline,17'

AGL/342'MSL.Railroad690'fromDER,549' leftof

centerline,23'AGL/317'MSL.Multipletreesbeginning

876'to3029'fromDER,341'to461' leftof centerline,up

to90'AGL/379'MSL.Multipletreesbeginning1886'

from DER, 103'rightof centerline,upto58'AGL/347'

MSL.

WATSONVILLE, CA

WATSONVILLE MUNI

TAKE-OFF MINIMUMS: Rwy 2, 1100-2 CATA,B, 1900-

2 CAT C,D or std. with a min. climb of: CAT A,B 330'

per NM to 2200; CAT C,D 460' per NM to 2400. Rwy 8,

std.withamin. climbof290'perNMto2200.Rwy20,

std.withamin. climbof330'perNMto2200.Rwy26,

std.with a min. climb of 330' perNM to 2200.

DEPARTUREPROCEDURE: Rwy 2 climbing right turn.

Rwy20,climbrunwayheading.Rwy26,climbingleft

turn. Allaircraft

NDBand climb to cross MOVERInt at or above 2200.

Climb in MOVER INT holding pattern (NE, right turns,

NOTE:Rwy 2, 40'AGLpole17'fromdepartureendof

runway,340' leftofcenterline.Rwy8,189'AGLtower

4696'fromdepartureendofrunway,1200'rightof

centerline.Rwy20,106'AGLtree954'fromdeparture

endofrunway,550' leftofcenterline. Rwy26,174'AGL

tree625'fromdepartureendofrunway,580' leftof

centerline.

WILLITS, CA

ELLS FIELD-WILLITS MUNI

DEPARTUREPROCEDURE: Rwy16,use

MENDOCINORNAV DEPARTURE. Rwy 34,use

FLUEN RNAV DEPARTURE.

WILLOWS, CA

WILLOWS-GLENN COUNTY (WLW)

AMDT 1A 10182 (FAA)

DEPARTUREPROCEDURE: Rwy 13,climbingright

turn.Rwy16, Rwys31,34, climbing

left turn. Allaircraft climb direct to MXWVORTAC.

Aircraft departing MXWVortac R-330 CWR-220, climb

on course.Allothers continueclimbinMXWholding

NOTE:Rwy 34, 55'AGL pole 530' from DER, 430'right of

centerline.Pole917'fromDER,404'rightof centerline,

55'AGL/193'MSL.

23 SEP 2010 to 21 OCT 2010

23 SEP 2010 to 21 OCT 2010

NOT FOR NAVIGATION

NOT FOR NAVIGATION

General notes

Takeoff minimums for the departure and obstacles in the departure path

Departure instructions

ODP charted graphically
1-36

Figure 1-31. Fly-over and fly-by waypoints.

NOT FOR NAVIGATION

A fly-over (FO) waypoint precludes any turn until the waypoint is overflown.

A fly-by (FB) waypoint requires the use of turn

anticipation to avoid overshooting the next segment. 

SID Altitudes

SID altitudes can be charted in four different ways. The 

first are mandatory altitudes, the second, minimum 

altitudes, the third, maximum altitudes and the fourth is a 

combination of minimum and maximum altitudes or also 

referred to as block altitudes. Below are examples of how 

each will be shown on a SID approach plate.

•	 Mandatory altitudes – 5500

•	 Minimum altitudes – 2300

•	 Maximum altitudes – 3300

•	 Combination of minimum and maximum – 7000

 4600

Some SIDs may still have “(ATC)” adjacent to a crossing 

altitude as shown in Figure 1-33 which implies that the 

crossing altitude is there to support an ATC requirement. 

A new charting standard has begun a process to remove, 

over a period of time, the ATC annotation. The Cowboy 

Four Departure (RNAV) shown in Figure 1-34 depicts the 

new charting standard without ATC annotations. When 

necessary, ATC may amend or delete SID crossing altitude 

restrictions; when doing so, ATC assumes responsibility 

for obstacle clearance until the aircraft is re-established 

laterally and vertically on the published SID route.

Pilot Responsibility for Use of RNAV Departures

RNAV usage brings with it multitudes of complications 

as it is being implemented. It takes time to transition, 

to disseminate information, and to educate current 

and potential users. As a current pilot using the NAS, 

you need to have a clear understanding of the aircraft 

equipment requirements for operating in a given RNP 

environment. You must understand the type of navigation 

system installed in your aircraft, and furthermore, you 

must know how your system operates to ensure that 

you can comply with all RNAV requirements. Operational 

information should be included in your AFM or its 

supplements. Additional information concerning how 

to use your equipment to its fullest capacity, including 

“how to” training, may be gathered from your avionics 

manufacturer. If you are in doubt about the operation of 

your avionics system and its ability to comply with RNAV 

requirements, contact the FAA directly through your local 

Flight Standards District Office (FSDO).RNAV departure 

procedures are being developed at a rapid pace to provide 

RNAV capabilities at all airports. With every chart revision 

cycle, new RNAV departures are being added for small 
1-37

Figure 1-32. Operation requirements for RNAV.

NOT FOR NAVIGATION

Aircraft system operation requirements

and large airports. These departures are flown in the same 

manner as traditional navigation-based departures; pilots 

are provided headings, altitudes, navigation waypoint, 

and departure descriptions. RNAV SIDs are found in the 

TPP with traditional departure procedures. 

Radar Departures

A radar departure is another option for departing an airport 

on an IFR flight. You might receive a radar departure if the 

airport does not have an established departure procedure, 

if you are unable to comply with a departure procedure, or 

if you request “No SIDs” as a part of your flight plan. Expect 

ATC to issue an initial departure heading if you are being 

radar vectored after takeoff, however, do not expect to 

be given a purpose for the specific vector heading. Rest 

assured that the controller knows your flight route and will 

vector you into position. By nature of the departure type, 

once you are issued your clearance, the responsibility for 

coordination of your flight rests with ATC, including the 

tower controller and, after handoff, the departure controller 

who will remain with you until you are released on course 

and allowed to “resume own navigation.”

For all practical purposes, a radar departure is the easiest 

type of departure to use. It is also a good alternative to a 

published departure procedure, particularly when none of 

the available departure procedures are conducive to your 

flight route. However, it is advisable to always maintain a 

detailed awareness of your location while you are being 

radar vectored by ATC. If for some reason radar contact is 

lost, you will be asked to provide position reports in order 

for ATC to monitor your flight progress. Also, ATC may 

release you to “resume own navigation” after vectoring you 

off course momentarily for a variety of reasons, including 

weather or traffic.

Upon initial contact, state your aircraft or flight number, 

the altitude you are climbing through, and the altitude 

to which you are climbing. The controller will verify that 

your reported altitude matches that emitted by your 

transponder. If your altitude does not match, or if you 

do not have Mode C capabilities, you will be continually 

required to report your position and altitude for ATC.

The controller is not required to provide terrain and 
1-38

Figure 1-33. Crossing altitude is there to support an ATC requirement.

0102 TCO12 ot 0102 PES 32, 4- WS

SW-4, 23 SEP 2010 to 21 OCT 2010

NOT FOR NAVIGATION

obstacle clearance just because ATC has radar contact 

with your aircraft. It remains your responsibility until the 

controller begins to provide navigational guidance in 

the form of radar vectors. Once radar vectors are given, 

you are expected to promptly comply with headings and 

altitudes as assigned. Question any assigned heading if you 

believe it to be incorrect or if it would cause a violation of 

a regulation, then advise ATC immediately and obtain a 

revised clearance. 

Diverse Vector Area

ATC may establish a minimum vectoring altitude (MVA) 

around certain airports. This altitude is based on terrain 

and obstruction clearance and provides controllers with 

minimum altitudes to vector aircraft in and around a 

particular location. However, it may be necessary to 

vector aircraft below this altitude to assist in the efficient 

flow of departing traffic. For this reason, an airport may 

have established a Diverse Vector Area (DVA). DVA design 

requirements are outlined in TERPS and allow for the 

vectoring of aircraft off the departure end of the runway 

below the MVA. The presence of a DVA is not published 

for pilots in any form, so the use of a textual ODP in a DVA 

environment could result in a misunderstanding between 

pilots and controllers. ATC instructions take precedence 

over an ODP. Most DVAs exist only at the busiest airports. 

[Figure 1-35]

Visual Climb Over Airport (VCOA)

A visual climb over airport (VCOA) is a departure option for 

an IFR aircraft, operating in VMC equal to or greater than the 

specified visibility and ceiling, to visually conduct climbing 

turns over the airport to the published "climb-to" altitude 

from which to proceed with the instrument portion of the 

departure. A VCOA is a departure option developed when 

obstacles farther than 3 SM from the airport require a CG 

of more than 200 FPNM. 

These procedures are published in the Take-Off 

Minimums and (Obstacle) Departure Procedures section 

of the TPP. [Figure 1-36] Prior to departure, pilots are 

required to notify ATC when executing the VCOA.

Noise Abatement Procedures

As the aviation industry continues to grow and air traffic 

increases, so does the population of people and businesses 

around airports. As a result, noise abatement procedures 

have become commonplace at most of the nation’s airports.

14 CFR Part 150 specifies the responsibilities of the FAA to 

investigate the recommendations of the airport operator in 

a noise compatibility program and approve or disapprove 

the noise abatement suggestions. This is a crucial step in 
1-39

Figure 1-34. New charting standard without ATC annotations.

NOT FOR NAVIGATION

NOT FOR NAVIGATION

SW-4, XX XXX 2011 to XX XXX 2011

SW-4, XX XXX 2011 to XX XXX 2011

SW-4, XX XXX 2011 to XX XXX 2011

SW-4, XX XXX 2011 to XX XXX 2011
1-40

Figure 1-35. Diverse vector area establishment criteria.

3 NM

MVA

Diverse vector areas allow for the maneuvering

of aircraft below the established minimum 

vectoring altitude for a particular airport.

Diverse Departure Criteria is used to 

identify obstacles in the departure path.

Figure 1-36. Examples of takeoff minimums obstacle clearance.

MYVVOR/DME, then via MYVVOR/DME R-263 to

YUBBAINTbeforeproceedingoncourse.

NOTE: Rwy 7, trees beginning 1117' from DER, 504'

rightof centerline,upto40'AGL/1708'MSL.Pole1365'

fromDER,600'rightof centerline, 59'AGL/1679'MSL.

Tree 3791' from DER, 700'right of centerline, 40'AGL/

1639' MSL. Rwy 25, tree 37' from DER, 479' left of

centerline,40'AGL/1528'MSL.Tree86'fromDER,461'

rightof centerline,40'AGL/1532'MSL.Fence301'from

DER, 244'right of centerline, 8'AGL/1508' MSL.Trees

beginning 660' from DER, 249'right of centerline, up to

40'AGL/1559'MSL.

BEALEAFB(KBAB)

MARYSVILLE, CA. . . . . . . . . .ORIG, 09155

DEPARTUREPROCEDURE:Rwy15,Climbona

Rwy33,

DER.

TAKE-OFFOBSTACLES:Rwy33,

BECKWOURTH,CA

NERVINO

TAKE-OFF MINIMUMS: Rwys 7, 25, 3500-3 for climb in

visualconditions.

DEPARTUREPROCEDURE: Rwys 7, 25, for climb in

visual conditions: crossNervinoAirportatorabove

8300beforeproceedingoncourse.

NOTE: Rwy7,road58'fromdepartureendofrunway,

469'rightof centerline, 15'AGL/4920' MSL. Pole310'

fromdepartureendofrunway,522'rightofcenterline,

49'AGL/4925'MSL. Pole528'fromdepartureendof

normal200'/NMclimbgradient,take-offmustoccurno

laterthan2000'priortodepartureendofrunway.

DEPARTUREPROCEDURE: Rwy 5, climbing right turn

proceedingoncourse. Rwy12, climbingleftturnvia

VORTACbeforeproceedingoncourse. Rwy30,

R-250toECAVORTACbeforeproceedingoncourse.

NOTE: Rwy5,bush17'fromdepartureendofrunway,67'

rightof centerline,6'AGL/52'MSL. Rwy 12,multiple

treesandbushbeginning240'fromdepartureendof

runway,286'rightof centerline,upto39'AGL/76'MSL.

Rwy30,multiplepoles,building,andterrainbeginning

66'fromdepartureendofrunway,228' leftofcenterline,

up to 65'AGL/225' MSL. Multiple poles beginning 949'

fromdepartureendofrunway,28'rightofcenterline,up

to42'AGL/103'MSL.

CHICO, CA

CHICO MUNI

DEPARTUREPROCEDURE: Rwys13L/R,climbing

right turn.Rwys31L/R,climbing left turn. Allaircraft,

climb via CIC R-205 to JINGOInt.Aircraft departing

inbound)todepartJINGOIntatorabove2800.

CLOVERDALE, CA

CLOVERDALE MUNI

TAKE-OFF MINIMUMS: Rwy 14, 400-2 or std. with a

min. climb of 280' perNM to 1500, then a min. climb of

260'perNMto3900. Rwy 32, NA.

DEPARTUREPROCEDURE: Rwy 14, climb directSTS

VOR/DME. Continue climb in holding pattern (NW

23 SEP 2010 to 21 OCT 2010

23 SEP 2010 to 21 OCT 2010

SAMPLE NOT FOR ACTUAL USE 

L2

TAKE-OFFMINIMUMSAND(OBSTACLE)DEPARTUREPROCEDURES 10266

AUBURN,CA

AUBURN MUNI (AUN)

AMDT 1 10098 (FAA)

TAKE-OFFMINIMUMS:Rwy7,300-1w/min. climbof

385' per NM to 2300, or 1100-3 for climb in visual

conditions.

DEPARTUREPROCEDURE:Rwy7, climbing left turn

MYVVOR/DME, then via MYVVOR/DME R-263 to

YUBBAINTbeforeproceedingoncourse,orfor climb

invisual conditions: crossAuburnMuniairportator

MYVVOR/DME R-094 to MYVVOR/DME, then via

MYVVOR/DME R-263 toYUBBAINT before

proceeding on course. Rwy25, climbingrightturnto

MYVVOR/DME, then via MYVVOR/DME R-263 to

YUBBAINTbeforeproceedingoncourse.

NOTE: Rwy 7, trees beginning 1117' from DER, 504'

rightof centerline,upto40'AGL/1708'MSL.Pole1365'

fromDER,600'rightof centerline, 59'AGL/1679'MSL.

Tree 3791' from DER, 700'right of centerline, 40'AGL/

1639' MSL. Rwy 25, tree 37' from DER, 479' left of

centerline,40'AGL/1528'MSL.Tree86'fromDER,461'

BISHOP, CA

EASTERN SIERRA RGNL

TAKE-OFFMINIMUMS:Rwys7,12,16,NA.Rwys25,

30,34, 4000-2 or std.with a min. climb of 350' perNM to

9000.

DEPARTUREPROCEDURE:Rwys25,30,turnright.

Rwy34,turnleft,climbnorthwestboundto13000viaBIH

R-322toNIKOLInt.

BYRON,CA

BYRON

TAKE-OFFMINIMUMS: Rwy23, NA-obstacles.

 Rwy 30, 200-1 or std. with a min. climb of 240' per NM to

300. Alternatively,withstandardtake-offminimumsanda

normal200'/NMclimbgradient,take-offmustoccurno

laterthan2000'priortodepartureendofrunway.

DEPARTUREPROCEDURE: Rwy 5, climbing right turn

proceedingoncourse. Rwy12, climbingleftturnvia

VORTACbeforeproceedingoncourse. Rwy30,

R-250toECAVORTACbeforeproceedingoncourse.

NOTE: Rwy5,bush17'fromdepartureendofrunway,67'

SAMPLE NOT FOR ACTUAL USE 
1-41

Figure 1-37. Noise abatement SID.

NE-1, 23 SEP 2010 ot 21 OCT 2010

NE-1, 23 SEP 2010 to 21 OCT 2010

NOT FOR NAVIGATION

Procedure designed for noise abatement purposes
1-42

ensuring that the airport is not unduly inhibited by noise 

requirements and that air traffic workload and efficiency 

are not significantly impacted, all while considering the 

noise problems addressed by the surrounding community.

While most DPs are designed for obstacle clearance and 

workload reduction, there are some SIDs that are developed 

solely to comply with noise abatement requirements. 

Portland International Jetport is an example of an airport 

where a SID was created strictly for noise abatement 

purposes as noted in the DP. [Figure 1-36] Typically, noise 

restrictions are incorporated into the main body of the 

SID. These types of restrictions require higher departure 

altitudes, larger climb gradients, reduced airspeeds, and 

turns to avoid specific areas. Noise restrictions may also 

be evident during a radar departure. ATC may require you 

to turn away from your intended course or vector you 

around a particular area. While these restrictions may seem 

burdensome, it is important to remember that it is your 

duty to comply with written and spoken requests from ATC.

Additionally, when required, departure instructions specify 

the actual heading to be flown after takeoff, as is the case in 

Figure 1-37 under the departure route description, “Climb 

via heading 112 degrees...” Some existing procedures specify, 

“Climb runway heading.” Over time, both of these departure 

instructions will be updated to read, “Climb heading 112 

degrees....” Runway heading is the magnetic direction that 

corresponds with the runway centerline extended (charted 

on the airport diagram), not the numbers painted on the 

runway. Pilots cleared to “fly or maintain runway heading” 

are expected to fly or maintain the published heading that 

corresponds with the extended centerline of the departure 

runway (until otherwise instructed by ATC), and are not to 

apply drift correction (e.g., RWY 11, actual magnetic heading 

of the runway centerline 112.2 degrees, “fly heading 112 

degrees”). In the event of parallel departures, this prevents 

a loss of separation caused by only one aircraft applying a 

wind drift.

Procedural Notes

An important consideration to make during your flight 

planning is whether or not you are able to fly your chosen 

departure procedure as charted. 

DP Responsibilities

Responsibility for the safe execution of DPs rests on the 

shoulders of both ATC and the pilot. Without the interest 

and attention of both parties, the IFR system cannot work 

in harmony, and achievement of safety is impossible.

ATC, in all forms, is responsible for issuing clearances 

appropriate to the operations being conducted, assigning 

altitudes for IFR flight above the minimum IFR altitudes for 

a specific area of controlled airspace, ensuring the pilot has 

acknowledged the clearance or instructions, and ensuring 

the correct read back of instructions. Specifically related to 

departures, ATC is responsible for specifying the direction 

of takeoff or initial heading when necessary, obtaining pilot 

concurrence that the procedure complies with local traffic 

patterns, terrain, and obstruction clearance, and including 

DP as part of the ATC clearance when pilot compliance for 

separation is necessary.

The pilot has a number of responsibilities when simply 

operating in conjunction with ATC or when using DPs under 

an IFR clearance:

•	 Acknowledge receipt and understanding of an ATC

clearance.

•	 Readback anypart of a clearance that contains“hold

short” instructions.

•	 Request clarification of clearances.

•	 Request an amendment to a clearance if it is

unacceptable from a safety perspective.

•	 Promptly comply with ATC requests. Advise ATC

immediately if unable to comply with a clearance.

•	 You are required to contact ATC if you are unable to

comply with all-engines-operating climb gradients 

and climb rates. It is also expected that you are 

capable of maintaining the climb gradient outlined 

in either a standard or non-standard DP. If you 

cannot maintain a standard climb gradient or the 

climb gradient specified in an ODP, you must wait 

until you can depart under VMC.

When planning for a departure, pilots should:

•	 Considerthetypeofterrainandotherobstructionsin

the vicinity of the airport.

•	 Determine if obstacle clearance can be maintained

visually, or if they need to make use of a DP.

•	 Determine if an ODP or SID is available for the

departure airport.

•	 Determine what actions allow for a safe departure

out of an airport that does not have any type of 

affiliated DPs.

By simply complying with DPs in their entirety as published, 

obstacle clearance is guaranteed. Depending on the type 

of departure used, responsibility for terrain clearance 

and traffic separation may be shared between pilots and 

controllers.
1-43

Departures From Tower-Controlled Airports

Departing from a tower-controlled airport is relatively 

simple in comparison to departing from non-towered 

airport. Normally you request your IFR clearance through 

ground control or clearance delivery. Communication 

frequencies for the various controllers are listed on 

departure, approach, and airport charts, as well as the 

A/FD. At some airports, you may have the option of 

receiving a pre-taxi clearance. This program allows you 

to call ground control or clearance delivery no more 

than 10 minutes prior to beginning taxi operations and 

receive your IFR clearance. A pre-departure clearance 

(PDC) program that allows pilots to receive a clearance via 

data link from a dispatcher or a data link communications 

service provider, e.g. ARINC, is available for Part 121 and 

Part 135 operators. A clearance is given to the dispatcher, 

who in turn, relays it to the crew, enabling the crew to 

bypass communication with clearance delivery, thus 

reducing frequency congestion. Once you have received 

your clearance, it is your responsibility to comply with the 

instructions as given, and notify ATC if you are unable to 

comply with the clearance. If you do not understand the 

clearance, or if you think that you have missed a portion 

of the clearance, contact ATC immediately for clarification.

Departures From Airports Without an 

Operating Control Tower

There are hundreds of airports across the United States 

that operate successfully every day without the benefit of 

a control tower. While a tower is certainly beneficial when 

departing IFR, most other departures can be made with 

few challenges. As usual, you must file your flight plan at 

least 30 minutes in advance. During your planning phase, 

investigate the departure airport’s method for receiving 

an instrument clearance. You can contact the Automated 

Flight Service Station (AFSS) on the ground by telephone, 

and they will request your clearance from ATC. Typically, 

when a clearance is given in this manner, the clearance 

includes a void time. You must depart the airport before the 

clearance void time; if you fail to depart, you must contact 

ATC by a specified notification time, which is within 30 

minutes of the original void time. After the clearance void 

time, your reserved space within the IFR system is released 

for other traffic.

There are several other ways to receive a clearance at a nontowered airport. If you can contact the AFSS or ATC on the 

radio, you can request your departure clearance. However, 

these frequencies are typically congested, and they may 

not be able to provide you with a clearance via the radio. 

You also can use a Remote Communications Outlet (RCO) 

to contact an AFSS if one is located nearby. Some airports 

have licensed UNICOM operators that can also contact ATC 

on your behalf and, in turn, relay your clearance from ATC. 

You are also allowed to depart the airport VFR, if conditions 

permit, and contact the controlling authority to request 

your clearance in the air. As technology improves, new 

methods for delivery of clearances at non-towered airports 

are being created.

Ground Communication Outlet

Ground Communication Outlets (GCO), have been 

developed in conjunction with the FAA to provide pilots 

flying in and out of non-towered airports with the capability 

to contact ATC and AFSS via very high frequency (VHF) 

radio to a telephone connection. This lets pilots obtain an 

instrument clearance or close a VFR/IFR flight plan. You can 

use four key clicks on your VHF radio to contact the nearest 

ATC facility and six key clicks to contact the local AFSS, but it

is intended to be used only as a ground operational tool. A 

GCO is an unstaffed, remote controlled ground-to-ground 

communication facility that is relatively inexpensive to 

install and operate. Installations of these types of outlets 

are scheduled at instrument airports around the country.

GCOs are manufactured by different companies including 

ARINC and AVTECH, each with different operating 

characteristics but with the ability to accomplish the same 

goal. This latest technology has proven to be an incredibly 

useful tool for communicating with the appropriate 

authorities when departing IFR from a non-towered airport. 

The GCO should help relieve the need to use the telephone 

to call ATC and the need to depart into marginal conditions 

just to achieve radio contact. GCO information is listed on 

airport charts and instrument approach charts with other 

communications frequencies. Signs may also be located on 

an airport to notify you of the frequency and proper usage.

See and Avoid Techniques

Meteorological conditions permitting, you are required 

to use “see and avoid” techniques to avoid traffic, terrain, 

and other obstacles. To avoid obstacles during a departure, 

the takeoff minimums may include a non-standard ceiling 

and visibility minimum. These are given to pilots so they 

can depart an airport without being able to meet the 

established climb gradient. Instead, they must see and 

avoid obstacles in the departure path. In these situations, 

ATC provides radar traffic information for radar-identified 

aircraft outside controlled airspace, workload permitting, 

and safety alerts to pilots believed to be within an unsafe 

proximity to obstacles or aircraft.

VFR Departures

There may be times when you need to fly an IFR flight 

plan due to the weather you will encounter at a later time 
1-44

(or if you simply wish to fly IFR to remain proficient), but 

the weather outside is clearly VFR. It may be that you can 

depart VFR, but you need to get an IFR clearance shortly 

after departing the airport. A VFR departure can be used as 

a tool that allows you to get off the ground without having 

to wait for a time slot in the IFR system, however, departing 

VFR with the intent of receiving an IFR clearance in the air 

can also present serious hazards worth considering.

A VFR departure dramatically changes the takeoff 

responsibilities for you and for ATC. Upon receiving 

clearance for a VFR departure, you are cleared to depart; 

however, you must maintain separation between yourself 

and other traffic. You are also responsible for maintaining 

terrain and obstruction clearance, as well as remaining in 

VFR weather conditions. You cannot fly in IMC without first 

receiving your IFR clearance. Likewise, a VFR departure 

relieves ATC of these duties and basically requires them 

only to provide you with safety alerts as workload permits.

Maintain VFR until you have obtained your IFR clearance 

and have ATC approval to proceed on course in accordance 

with your clearance. If you accept this clearance and are 

below the minimum IFR altitude for operations in the area, 

you accept responsibility for terrain/obstruction clearance 

until you reach that altitude.
2-1

Introduction

The en route phase of flight is defined as that segment of 

flight from the termination point of a departure procedure 

to the origination point of an arrival procedure. The 

procedures employed in the en route phase of flight are 

governed by a set of specific flight standards established by 

Title 14 of the Code of Federal Regulations (14 CFR) [Figure 

2-1], Federal Aviation Administration (FAA) Order 8260.3, 

United States Standard for Terminal Instrument Procedures 

(TERPS), and related publications. These standards establish 

courses to be flown, obstacle clearance criteria, minimum 

altitudes, navigation performance, and communications 

requirements.

En Route Operations

Chapter 2
2-2

Figure 2-1. Code of Federal Regulations, Title 14 Aeronautics and Space.

Figure 2-2. Airways depicted on an aeronautical chart.

En Route Navigation

En route instrument flight rules (IFR) navigation is evolving 

from the ground-based navigational aid (NAVAID) airway 

system to a sophisticated satellite and computer-based 

system that can generate courses to suit the operational 

requirements of almost any flight. The FAA Global 

Navigation Satellite System (GNSS) provides satellite-based 

positioning, navigation, and timing services in the United 

States to enable performance-based operations for all 

phases of flight, to include en route navigation. 

14 CFR Part 91, section 91.181, is the basis for the course 

to be flown. Unless authorized by ATC, to operate an 

aircraft within controlled airspace under IFR, pilots must 

either fly along the centerline when on a Federal airway 

or, on routes other than Federal airways, along the direct 

course between NAVAIDs or fixes defining the route. The 

regulation allows maneuvering to pass well clear of other 

air traffic or, if in visual flight rules (VFR) conditions, to clear 

the flightpath both before and during climb or descent.

Airways

Airway routing occurs along pre-defined pathways called 

airways. [Figure 2-2] Airways can be thought of as threedimensional highways for aircraft. In most land areas of 

the world, aircraft are required to fly airways between the 

departure and destination airports. The rules governing 

airway routing, Standard Instrument Departures (SID) 

and Standard Terminal Arrival (STAR), are published flight 

procedures that cover altitude, airspeed, and requirements 

for entering and leaving the airway. Most airways are eight 

nautical miles (14 kilometers) wide, and the airway flight 

levels keep aircraft separated by at least 500 vertical feet 

from aircraft on the flight level above and below when 

operating under VFR. When operating under IFR, between 

the surface and an altitude of Flight Level (FL) 290,no 

aircraft should come closer vertically than 1,000 feet. 

Above FL290 , no aircraft should come closer than 2,000 

feet except in airspace where Reduced Vertical Separation 

Minima (RVSM) can be applied in which case the vertical 

separation is reduced to 1,000 ft. Airways usually intersect 

at NAVAIDs that designate the allowed points for changing 

from one airway to another. Airways have names consisting 

of one or more letters followed by one or more digits (e.g., 

V484 or UA419).

The en route airspace structure of the National Airspace 

System (NAS) consists of three strata. The first stratum low 

altitude airways in the United States can be navigated 
2-3

Figure 2-3. Victor airways. Figure 2-4. Jet routes.

Figure 2-5. Air Route Traffic Control Centers.

ZID

ZMP

ZOB

ZBW

ZNY

ZNY

ZDC

ZAU

ZKC

ZME

ZTL

ZJX

ZMA

ZHU

ZFW ZAB

ZDV

ZLA

ZOA

ZLC

ZSE

ZHN

ZAN

Cleveland Center 

Albuquerque Center

Seattle Center

Atlanta Center

Chicago Center

Boston Center

Washington 

Center (DC)

Denver Center

Fort Worth Center

Houston Center

Indianapolis 

Center

Jacksonville Center

 Kansas City Center

Los Angeles Center

Salt Lake City Center

Miami Center

Memphis Center

Minneapolis Center

New York 

Oakland Center Center

Honolulu

Center

Anchorage

Center

using NAVAIDs, have names that start with the letter V, and 

are called Victor Airways. [Figure 2-3] They cover altitudes 

from approximately 1,200 feet above ground level (AGL) 

up to, but not including 18,000 feet above mean sea level 

(MSL). The second stratum high altitude airways in the 

United States all have names that start with the letter J, 

and are called Jet Routes. [Figure 2-4] These routes run 

from 18,000 feet to 45,000 feet. The third stratum allows 

random operations above flight level (FL) 450. The altitude 

separating the low and high airway structure varies from 

county to country. For example, in Switzerland it is 19,500 

feet and 25,000 feet in Egypt.

Air Route Traffic Control Centers

The FAA defines an Air Route Traffic Control Center (ARTCC) 

as a facility established to provide air traffic control (ATC) 

service to aircraft operating on IFR flight plans within 

controlled airspace, principally during the en route phase 

of flight. When equipment capabilities and controller 

workload permit, certain advisory/assistance services may 

be provided to VFR aircraft.

ARTCCs, usually referred to as Centers, are established 

primarily to provide air traffic service to aircraft operating 

on IFR flight plans within the controlled airspace, and 

principally during the en route phase of flight. There are 
2-4

Figure 2-6. Boston Air Route Traffic Control Center.

Figure 2-7. Flight progress strips.

21 ARTCC’s in the United States. [Figure 2-5] Any aircraft 

operating under IFR within the confines of an ARTCC’s 

airspace is controlled by air traffic controllers at the Center. 

This includes all sorts of different types of aircraft: privately 

owned single engine aircraft, commuter airlines, military 

jets, and commercial airlines.

The largest component of the NAS is the ARTCC. Each 

ARTCC covers thousands of square miles encompassing 

all or part of several states. ARTCCs are built to ensure safe 

and expeditious air travel. All Centers operate 7-days a 

week, 24-hours a day, and employ a combination of several 

hundred ATC specialists, electronic technicians, computer 

system specialists, environmental support specialists, and 

administrative staff. Figure 2-6 is an example of the Boston 

ARTCC. The green lines mark the boundaries of the Boston 

Center area, and the red lines mark the boundaries of 

Military Operations Areas (MOAs), Prohibited, Restricted, 

Alert, and Warning Areas.

Safe Separation Standards

The primary means of controlling aircraft is accomplished 

by using highly sophisticated computerized radar systems. 

In addition, the controller maintains two-way radio 

communication with aircraft in his or her sector. In this 

way, the specialist ensures that the aircraft are separated 

by the following criteria: 

	 •	 Laterally—5 miles

	 •	 Vertically—

•	 1,000 feet (if the aircraft is below FL290, or

between FL290 and FL410 for RVSM compliant 

aircraft) 

•	 2,000 feet (if the aircraft is at FL290 or above)

The controllers can accomplish this separation by issuing 

instructions to the pilots of the aircraft involved. Altitude 

assignments, speed adjustments, and radar vectors are 

examples of instructions that might be issued to aircraft.

En route control is handled by pinpointing aircraft positions 

through the use of flight progress strips. These strips are 

pieces of printed paper containing pertinent information 

extracted from the pilot’s flight plan. These strips are 

printed 20 minutes prior to an aircraft reaching each 

Center’s sector. A flight progress strip tells the controller 

everything needed to direct that aircraft. If the flight 

progress strips of each aircraft approaching a sector are 

arranged properly, it is possible to determine potential 

conflicts long before the aircraft are even visible on the 

Center controller’s display. In areas where radar coverage 

is not available, this is the sole means of separating aircraft.

The strips, one for each en route point from which the 

pilot reports his or her position, are posted on a slotted 

board in front of the air traffic controller. [Figure 2-7] At a 

glance, he or she is able to see certain vital data: the type 

of airplane and who is flying it (airline, business, private, 

or military pilot), aircraft registration number or flight 

number, route, speed, altitude, airway designation, and the 

estimated time of arrival (ETA) at destination. As the pilot 

calls in the aircraft’s position and time at a predetermined 

location, the strips are removed from their slots and filed. 

Any change from the original flight plan is noted on the 
2-5

Figure 2-8. Fort Worth Air Route Traffic Control Center.

Figure 2-9. Low altitude sectors.

Figure 2-10. Intermediate altitude sectors.

Figure 2-11. High altitude sectors.

Figure 2-12. Ultra high altitude sectors.

strips as the flight continues. Thus, from a quick study of 

the flight progress board, a controller can assess the overall 

traffic situation and can avoid possible conflicts.

Figure 2-8 shows the Fort Worth, Texas Air Route Traffic 

Control Center (ZFW) and the geographical area that it 

covers. The Center has approximately 350 controllers. Most 

are certified and some are in on-the-job training.

Sectors

The airspace controlled by a Center may be further 

administratively subdivided into smaller, manageable 

pieces of airspace called sectors. A few sectors extend from 

the ground up, but most areas are stratified into various 

levels to accommodate a wide variety of traffic. Each sector 

is staffed by a set of controllers and has a unique radio 

frequency that the controller uses to communicate with 

the pilots. As aircraft transition from one sector to another, 

they are instructed to change to the radio frequency used 

by the next sector. Each sector also has secure landline 

communications with adjacent sectors, approach controls, 

areas, ARTCCs, flight service centers, and military aviation 

control facilities.
2-6

Figure 2-13. Air Route Traffic Control Centers and sector frequencies.

NOT FOR NAVIGATION MEMPHIS

Huntsville

120.8 307.0

ATLANTA

Chattanooga

132.05 353.8

MEMPHIS

ATLANTA

The ARTCC at Fort Worth, Texas is subdivided into sectors 

that are categorized as follows:

•	 Eighteen low altitude sectors. [Figure 2-9]

•	 Seven intermediate altitude sectors. [Figure 2-10]

•	 Sixteen high altitude sectors. [Figure 2-11]

•	 One ultra high altitude sector. [Figure 2-12]

From one to three controllers may work a sector, depending 

upon the amount of air traffic. Each controller is assigned 

to work the positions within an area of specialization.

Controllers have direct communication with pilots, with 

surrounding sectors and Centers, plus the towers and Flight 

Service Stations (FSS) under their jurisdiction. Each control 

position is equipped with computer input and readout 

devices for aircraft flight plan data.

The Center controllers have many decision support 

tools (computer software programs) that provide vital 

information to assist the controllers in maintaining safe 

separation distances for all aircraft flying through their 

sector. For example, one tool available allows the controller 

to display the extended route of any aircraft on the radar 

screen called a vector line. This line projects where the 

aircraft will be within a specified number of minutes, 

assuming the aircraft does not change its course. This is 

a helpful tool to determine if aircraft flying intersecting 

routes pass safely within the separation standard, or if they 

conflict with each other. In addition to vector lines, the 

controller can also display a route line for any given aircraft 

on his or her radar screen. This tells the controller where 

a particular aircraft is in specified number of minutes, as 

well as the path the aircraft will fly to get there. Decision 

support tools such as these help each controller look ahead 

and avoid conflicts.

In-flight Requirements and Instructions

The CFRs require the pilot in command under IFR in 

controlled airspace to continuously monitor an appropriate 

Center or control frequency. When climbing after takeoff, 

an IFR flight is either in contact with a radar-equipped local 

departure control or, in some areas, an ARTCC facility. As 

a flight transitions to the en route phase, pilots typically 

expect a handoff from departure control to a Center 

frequency if not already in contact with the Center.

The FAA National Aeronautical Navigation Products 

(AeroNav Products), formerly known as the National 

Aeronautical Charting Office (NACO), publishes en route 

charts depicting Centers and sector frequencies. [Figure 

2-13] During handoff from one Center to another, the 

previous controller assigns a new frequency. In cases where 

flights may be out of range, the Center frequencies on the 

face of the chart are very helpful. In Figure 2-13, notice 

the boundary between Memphis, Tennessee and Atlanta, 
2-7

Georgia Centers, and the remote sites with discrete very 

high frequency (VHF) and ultra high frequency (UHF) for 

communicating with the appropriate ARTCC. These Center 

frequency boxes can be used for finding the nearest 

frequency within the aircraft range. They also can be used 

for making initial contact with the Center for clearances. 

The exact location for the Center transmitter is not shown, 

although the frequency box is placed as close as possible 

to the known location.

During the en route phase, as a flight transitions from one 

Center facility to the next, a handoff or transfer of control 

is required as previously described. The handoff procedure 

is similar to the handoff between other radar facilities, such 

as departure or approach control. During the handoff, 

the controller whose airspace is being vacated issues 

instructions that include the name of the facility to contact, 

appropriate frequency, and other pertinent remarks.

Accepting radar vectors from controllers does not relieve 

pilots of their responsibility for safety of flight. Pilots must 

maintain a safe altitude and keep track of their position, 

and it is their obligation to question controllers, request 

an amended clearance, or, in an emergency, deviate from 

their instructions if they believe that the safety of flight 

is in doubt. Keeping track of altitude and position when 

climbing, and during all other phases of flight, are basic 

elements of situational awareness (SA). Aircraft equipped 

with an enhanced ground proximity warning system 

(EGPWS), terrain awareness and warning system (TAWS), 

or traffic alert and collision avoidance system (TCAS) help 

pilots detect and/or correct for potential unsafe proximities 

to other aircraft and increases pilot(s) situational awareness. 

Regardless of equipment, pilots must always maintain SA 

regarding their location and the location of traffic in their 

vicinity.

High Altitude Area Navigation Routing

Special high altitude routes allow pilots routing options for 

flight within the initial high altitude routing (HAR) Phase 

I expansion airspace. Pilots are able to fly user-preferred 

routes, referred to as non-restrictive routing (NRR), between 

specific fixes described by pitch (entry into) and catch (exit 

out of) fixes in the HAR airspace. Pitch points indicate an 

end of departure procedures, preferred IFR routings, or 

other established routing programs where a flight can 

begin a segment of NRR. The catch point indicates where 

a flight ends a segment of NRR and joins published arrival 

procedures, preferred IFR routing, or other established 

routing programs.

The HAR Phase I expansion airspace is defined as that 

airspace at and above FL 350 in fourteen of the western 

and southern ARTCCs. The airspace includes Minneapolis 

(ZMP), Chicago (ZAU), Kansas City (ZKC), Denver (ZDV), 

Salt Lake City (ZLC), Oakland (ZOA), Seattle Centers (ZSE), 

Los Angeles (ZLA), Albuquerque (ZAB), Fort Worth (ZFW), 

Memphis (ZME), and Houston (ZHU). Jacksonville (ZJX) 

and Miami (ZMA) are included for east-west routes only. To 

develop a flight plan, select pitch and catch points which 

can be found in the Airport/Facility Directory (A/FD) based 

upon your desired route across the Phase I airspace. Filing 

requirements to pitch points, and from catch points, remain 

unchanged from current procedures. For the portion of the 

route between the pitch and catch points, NRR is permitted. 

Where pitch points for a specific airport are not identified, 

aircraft should file an appropriate departure procedure (DP), 

or any other user preferred routing prior to the NRR portion

of their routing. Where catch points for a specific airport 

are not identified aircraft should file, after the NRR portion 

of their routing, an appropriate arrival procedure or other 

user preferred routing to their destination.

Additionally, information concerning the location and 

schedule of special use airspace (SUA) and Air Traffic 

Control Assigned Airspace (ATCAA) can be found at http://

sua.faa.gov. ATCAA refers to airspace in the high altitude 

structure supporting military and other special operations. 

Pilots are encouraged to file around these areas when they 

are scheduled to be active, thereby avoiding unplanned 

reroutes around them.

In conjunction with the HAR program, area navigation 

(RNAV) routes have been established to provide for a 

systematic flow of air traffic in specific portions of the en 

route flight environment. The designator for these RNAV 

routes begin with the letter Q, for example, Q-501. Where 

those routes aid in the efficient orderly management of air 

traffic, they are published as preferred IFR routes.

Preferred IFR Routes

Preferred IFR routes are established between busier airports 

to increase system efficiency and capacity. They normally 

extend through one or more ARTCC areas and are designed 

to achieve balanced traffic flows among high density 

terminals. IFR clearances are issued on the basis of these 

routes except when severe weather avoidance procedures 

or other factors dictate otherwise. Preferred IFR routes are 

listed in the A/FD and can also be found on www.fly.faa.

gov, which requires entering the following data: departure 

airport designator, destination, route type, area, aircraft 

types, altitude, route string, direction, departure ARTCC, 

and arrival ARTCC. [Figure 2-14] If a flight is planned to or 

from an area having such routes but the departure or arrival 

point is not listed in the A/FD, pilots may use that part of a 

preferred IFR route that is appropriate for the departure or 
2-8

Figure 2-15 Preferred IFR routes.

Figure 2-14. Airport/Facility Directory.

arrival point listed. Preferred IFR routes are correlated with 

departure procedures (DPs) and STARs and may be defined 

by airways, jet routes, direct routes between NAVAIDs, 

waypoints, NAVAID radials/ distance measuring equipment 

(DME), or any combinations thereof.

Preferred IFR routes are published in the A/FD for the 

low and high altitude stratum. If they begin or end with 

an airway number, it indicates that the airway essentially 

overlies the airport and flights normally are cleared directly 

on the airway. Preferred IFR routes beginning or ending with 

a fix indicate that pilots may be routed to or from these fixes 

via a SID route, radar vectors, or a STAR. Routes for major 

terminals are listed alphabetically under the name of the 

departure airport. Where several airports are in proximity, 

they are listed under the principal airport and categorized as

 a metropolitan area (e.g., New York Metro Area). One way 

preferred IFR routes are listed is numerically, showing the 

segment fixes and the direction and times effective. Where 

more than one route is listed, the routes have equal priority 

for use. Official location identifiers are used in the route 

description for very high frequency omnidirectional ranges 

(VORs) and very high frequency omnidirectional ranges/ 

tactical air navigation (VORTACs), and intersection names 

are spelled out. The route is direct where two NAVAIDs, an 

intersection and a NAVAID, a NAVAID and a NAVAID radial 

and distance point, or any navigable combination of these 

route descriptions follow in succession.

A system of preferred IFR routes helps pilots, flight crews, 

and dispatchers plan a route of flight to minimize route 

changes, and to aid in the efficient, orderly management 
2-9

Figure 2-16 14 CFR Part 95 sub-routes.

Uncontrolled airspace

BCD vortac (shutdown)

ABC vortac

Sub-route V-98

CDE vortac

V-98

V-98

Obstacle study and flight 

inspection of sub-route required

(Centerline must be in 

controlled airspace)

Figure 2-17 Non-Part 95 sub-routes.

Uncontrolled airspace

BCD vortac (shutdown)

ABC vortac

Off-airway sub-route

CDE vortac

V-98

V-98

Obstacle study and flight 

inspection of sub-route required

of air traffic using Federal airways. Preferred IFR routes 

are designed to serve the needs of airspace users and 

to provide for a systematic flow of air traffic in the major 

terminal and en route flight environments. Cooperation by 

all pilots in filing preferred routes results in fewer air traffic 

delays and better efficiency for departure, en route, and 

arrival air traffic service. [Figure 2-15]

Substitute Airway or Route Structures

ARTCCs are responsible for specifying essential substitute 

airway or route segments (sub-routes) and fixes for use 

during scheduled or unscheduled VOR/VORTAC shutdowns. 

Scheduled shutdowns of navigational facilities require 

planning and coordination to ensure an uninterrupted flow 

of air traffic. Aeronautical Navigation Products (AJV-3), in 

coordination with the ARTCCs, determine when the length 

of outages or other factors require publication of subroutes and Flight Instpection Services (AJW-3) provides 

flight inspection services, obstacle clearance verification, 

certification, and final approval of substitute routes. 

Substitute Airway En Route Flight Procedures

A schedule of proposed facility shutdowns within the region 

is maintained and forwarded as far in advance as possible 

to enable the substitute routes to be published. Substitute 

routes are normally based on VOR/VORTAC facilities 

established and published for use in the appropriate 

altitude strata. In the case of substitute routes in the upper 

airspace stratum, it may be necessary to establish routes by 

reference to VOR/VORTAC facilities used in the low altitude 

system. Non-directional (radio) beacon (NDB) facilities may 

only be used where VOR/VORTAC coverage is inadequate 

and ATC requirements necessitate use of such NAVAIDs. 

Where operational necessity dictates, NAVAIDs may be 

used beyond their standard service volume (SSV) limits that 

define the reception limits of unrestricted NAVAIDs, which 

are usable for random/unpublished route navigation, 
2-10

Figure 2-18 Sub-route wider than existing route.

GHI vortac HIJ vortac IJK vortac (L)

V-204 V-204

30

70

Obstacle study flight 

inspection and ESV’s 

required

GHI vortac IJK vortac (L)

HIJ vortac (shutdown)

SUB-ROUTE V-204

60*

90

provided that the routes can be given adequate frequency 

protection.

The centerline of substitute routes must be contained 

within controlled airspace [Figure 2-16], although substitute 

routes for off-airway routes may not be in controlled airspace. [Figure 2-17] Substitute routes are flight inspected 

to verify clearance of controlling obstacles and to check for 

satisfactory facility performance. If substitute routes do not 

overlie existing routes, or are wider than existing routes, 

map studies are required to identify controlling obstacles. 

[Figure 2-18] The format for describing substitute routes 

is from navigational fix to navigational fix. A minimum en 

route altitude (MEA) and a maximum authorized altitude 

(MAA) are provided for each route segment. Temporary 

reporting points may be substituted for the out-of-service 

facility and only those other reporting points that are 

essential for ATC. Normally, temporary reporting points 

over intersections are not necessary where Center radar 

coverage exists. A minimum reception altitude (MRA) is 

established for each temporary reporting point.

Tower En Route Control

Tower en route control (TEC) is an ATC program available 

to pilots that provides a service to aircraft proceeding to 

and from metropolitan areas. It links designated approach 

control areas by a network of identified routes made up 

of the existing airway structure of the NAS, which makes 

it possible to fly an IFR flight without leaving approach 

control airspace. [Figure 2-19] This service is designed 

to help expedite air traffic and reduces ATC and pilot 

communication requirements. The program is generally 

used by non-turbojet aircraft operating at and below 

10,000 feet but a few facilities, such as Milwaukee and 

Chicago, have allowed turbojets to proceed between 

city pairs. Participating flights are relatively short with a 

duration of 2 hours or less.

TEC is referred to as tower en route, or tower-to-tower, and 

allows flight beneath the en route structure. TEC reallocates 

airspace both vertically and geographically to allow flight 

planning between city pairs while remaining with approach 

control airspace. All users are encouraged to use the TEC 

route descriptions located in the A/FD when filing flight 

plans. [Figure 2-20] All published TEC routes are designed 

to avoid en route airspace, and the majority is within radar 

coverage.

Tower En Route Control Route Descriptions

The graphic depiction of TEC routes located in the A/FD is 

not to be used for navigation or for detailed flight planning 

because not all city pairs are depicted. The information is 

intended to show geographic areas connected by TEC. 

[Figure 2-19] Pilots should refer to the route descriptions 

for specific flight planning.
2-11

Figure 2-19. Tower En Route Control (TEC) Northeast U.S. (Eastern).

TOWER EN ROUTE CONTROL (TEC)

Northeast U.S. (Eastern)

(Lines connecting airports

depict adjacent approach

control facilities) 

CLE

Radar approach control area

PIT

CKB

ROA

RIC

IAD

HAR

RDG

ABE

NYC

ACY

PHL WRI

BWI

DOV

AVP

BGM

ELM

DCA

PXT

ORF

CRW

GSO

ERI

BUF

YNG

CAK

HTS

DC

PENNSYLVANIA

WEST VIRGINIA

VIRGINIA

MARYLAND NEW JERSEY

DELAWARE

LEGEND

As shown in Figure 2-20, the route description contains four 

columns of information. The first column is the approach 

control area within which the departure airport is located, 

which are listed alphabetically. The second column shows 

the specific route, airway, or radial that is to be used. 

The third column shows the highest altitude allowed for 

the route, and the fourth shows the destination airport, 

which are also listed alphabetically. When flight planning, 

it is important to always check current publications for 

information about the departure and destination airport. 

Routes are effective only during each respective terminal 

facilities normal operating hours. Always check NOTAMs 

to ensure that appropriate terminal facilities are operating 

for the planned flight time. Altitudes are always listed in 

thousands of feet. ATC may request that the pilot changes 

altitude while in flight in order to maintain the flight within 

approach control airspace. ATC provides radar monitoring 

and, if necessary, course guidance if the highest altitude 

assigned is below the MEA. 

Shown in Figure 2-21, under the second column, the word 

“Direct” appears as the route when radar vectors are used 

or no airway exists. This also indicates that a SID or STAR 

may be assigned by ATC. When a NAVAID or intersection 

identifier appears with no airway immediately preceding 

or following the identifier, the routing is understood to be 

direct to or from that point unless otherwise cleared by ATC. 

Routes beginning and ending with an airway indicate that 

the airway essentially overflies the airport, or radar vectors 

are issued. [Figure 2-21] Where more than one route is listed 

to the same destination, ensure that the correct route for 

the type of aircraft classification has been filed. These are 

denoted after the route in the altitude column using J (jet 

powered), M (turbo props/special, cruise speed 190 knots 

or greater), P (non-jet, cruise speed 190 knots or greater), 

or Q (non-jet, cruise speed 189 knots or less). [Figure 2-22] 

Although all airports are not listed under the destination 
2-12

Figure 2-20. Baltimore Airport/Facility Directory, Tower En Route Control route descriptions.

 Highest 

 Route 

Altitude Destination

............ V93 LRP V39 ETX 

7000 Allentown

............ V268 LEEAH V229 

7000 Atlantic City

............ V268 ENO V16 JFK V229 HFD CLOWW (Single 7000 Bangor

 engine and /E, /F. /G only) 

............ V268 ENO V16 JFK V229 HFD CLOWW (Single 7000 Bar Harbor

 engine and /E, /F. /G only) 

............ V93 LRP V499 

7000 Binghamton

............ V268 ENO V16 JFK V229 

7000 Boston (North)

 HFD HFDO53 DREEM (Single engine only) 

............ V268 ENO V16 JFK V229 HFD V3 WOONS 7000 Boston 

 (Single engine only) 

............ V268 ENO V16 JFK V229 BDR BDR014 

7000 Boston

 JUDDS (Single engine only) 

............ V268 ENO V16 JFK V229 BDR (Single 7000 Bradley

 engine only)

............ V268 ENO V16 JFK V229 BDR (Single 7000 Bridgeport

 engine only)

............ V31 HAR 

7000 Capital City

............ V268 ENO 

7000 Dover AFB

............ V44 MRB 

6000 Dulles

............ V268 ENO V16 JFK V229 BRD MAD 

7000 Groton

 MAD126 MONDI (Single engine only) 

TOWER EN ROUTE CONTROL

Approach Control Area

(Including Satellites)

Baltimore

Figure 2-21. Allentown Airport/Facility Directory, Tower En Route Control route descriptions.

 Highest 

 Route 

Altitude Destination

............ EJC V149 LHY 

8000 Albany

............ ETX LHY 

8000 Albany

............ V149 MAZIE ARD CYN 

5000 Atlantic City

............ V93 LRP 

8000 Baltimore

............ EXT V162 DUMMR V93 LRP 

6000 Baltimore

............ V39 LRP 

8000 Baltimore

............ V130 

10000 Bradley 

............ Direct 

10000 Bradley

............ FJC STW 

5000 Caldwell

............ (2) EXT V30 SBJ 

5000 Farmingdale

............ ETX V162 HAR 

8000 Harrisburg

............ Direct 

10000 Hartford

............ EXT ETX004 WEISS 

4000 Hazleton

............ EXT V39 

4000 Lancaster

 

TOWER EN ROUTE CONTROL

Approach Control Area

(Including Satellites)

Allentown
2-13

Figure 2-23. Low frequency airway G13.

Figure 2-22. Atlantic City Airport/Facility Directory, Tower En Route Control route descriptions.

 Highest 

 Route 

Altitude Destination

............ V229 DIXIE V276 ARD 

6000 Allentown

............ V1 DIXIE V276 ARD (Single engine only) 

6000 Allentown

............ V1 ATR V308 OTT 

4000 Andrews, AFB

............ LEEAH V268 BAL 

4000 Baltimore

............ V1 JFK V229 HFD CLOWM (Single engine and 6000 Bangor

 /E, /F, /G only)

............ V1 JFK V229 HFD CLOWM (Single engine and 6000 Bar Harbor

 /E, /F, /G only)

............ V1 JFK V229 HFD HFD053 DREEM (Single 6000 Boston (North)

 (Single engine only)

............ V1 JFK V229 HFD V3 WOONS (Single engine 6000 Boston

 only

............ V1 JFK V229 HFD FOSTY WOONS (Single 6000 Boston

 engine only)

............ V1 JFK V229 BDR BDR14 JUDDS (Single 6000 Bradley

 engine only)

............ V184 ZIGGI JFK 210 JFK V229 BDR (Twins 6000 Bridgeport

 only, n/a between 1400-2100)

............ HOWIE V1 JFK V229 BDR (Single engine only) 6000 Bridgeport

............ V184 00D DQO V469 HAR 

4000 Capital City

 

TOWER EN ROUTE CONTROL

Approach Control Area

(Including Satellites)

Atlantic City

column, IFR flights may be planned to satellite airports in 

the proximity of major airports via the same routing. When 

filing flight plans, the coded route identifier (i.e., BURL 1, 

VTUL4, or POML3) may be used in lieu of the route of flight.

Airway and Route System

There are three fixed route systems established for 

air navigation purposes. They are the Federal airway 

consisting of VOR (low victor airways, high jet routes), 

NDB (low or medium frequency) and the RNAV route 

system. To the extent possible, these route systems are 

aligned in an overlying manner to facilitate transition 

between each. The majority of the airways are made up 

of victor airways, jet routes, and RNAV, but some low/

medium frequency (L/MF) airways and routes are still 

being used in Alaska and one other that is located off 

the coast of North Carolina and is called Green 13 (G13). 

[Figure 2-23]

Airway/Route Depiction

IFR en route charts show all IFR radio NAVAIDs that have 

been flight-checked by the FAA and are operational. 

The FAA, AeroNav Products publishes and distributes 

U.S. Government Civil Aeronautical Charts and flight 

information publications. IFR en route navigation 

information is provided on three charts: IFR en route low 

altitude chart, IFR en route high altitude chart, and Terminal 
2-14

Figure 2-24. IFR en route low altitude (left) and high altitude (right) charts.

Area Chart (TAC). [Figure 2-24A and B]

IFR En Route Low Altitude Chart

En route low altitude charts provide aeronautical information 

for navigation under IFR conditions below 18,000 feet MSL. 

Low altitude charts [Figure 2-25] include the following 

information: 

•	 Airways [Figure 2-25A]

•	 RNAV routes [Figure 2-25B]

•	 Limits of controlled airspace [Figure 2-25C]

•	 VHFradioaidstonavigation(frequency,identification,

channel, geographic coordinates) [Figure 2-25D]

•	 Airportsthathaveaninstrumentapproachprocedure

or a minimum 3,000 foot hard surface runway 

[Figure 2-25E]

•	 Off-route obstruction clearance altitudes (OROCA)

[Figure 2-25F]

•	 Reporting points [Figure 2-25G]

•	 Special use airspace areas [Figure 2-25H]

•	 Military training routes [Figure 2-25I]

IFR aeronautical charts depict VOR airways (airways based 

on VOR or VORTAC NAVAIDs) in black, identified by a “V” 

(Victor) followed by the route number (e.g., V12). [Figure 

2-26] LF/MF airways (airways based on LF/MF NAVAIDs) 

are sometimes referred to as colored airways because they 

are identified by color name and number (e.g., Amber One, 

charted as A1). Green and red airways are plotted east and 

west, and amber and blue airways are plotted north and 

south. Regardless of their color identifier, LF/MF airways 

are depicted in brown. [Figure 2-27]

Airway/route data, such as the airway identifications, 

bearings or radials, mileages, and altitude (e.g., MEA), 

minimum obstacle clearance altitude (MOCA), and MAA, 

are shown aligned with the airway and in the same color 

as the airway. [Figure 2-26]

All airways/routes that are predicated on VOR or VORTAC 

NAVAIDs are defined by the outbound radial from the 

NAVAID. Airways/routes that are predicated on LF/MF 

NAVAIDs are defined by the inbound bearing.

New low altitude RNAV routes have been created by the 

FAA. RNAV routes provide more direct routing for IFR 

aircraft and enhance the safety and efficiency of the NAS. In 

order to utilize these routes, aircraft must be equipped with 

IFR approved GNSS. In Alaska, when using RNAV routes, the 

aircraft must be equipped with Technical Standing Order 

(TSO)-145a and 146a equipment.

Low altitude RNAV only routes are identified by the letter 

“T” prefix, followed by a three digit number (T-200 to T-500). 

RNAV routes are depicted in aeronautical blue, as well as the 

RNAV route data, which includes the following [Figure 2-28]:

•	 Route line
2-15

Figure 2-25. Information found on en route low altitude charts.

E VALENTINE

Miller Fld

(VTN)

2596 47 L

 VALENTINE

 314 VTN 

V60

29

26

35

10000

V190

53

27

153

TAFOY

F

x

232

154

152

9

D

L 83

28.55

G

A

V4

30

Victor Route (with RNAV/GPS 

MEA shown in blue)

*35 00

 3 50 0G

 S 50 0

310

B

T270

70

5000G

*5400

6000G

087

67

268 088

NGOZI

GRANT

269

T270

Waypoint

Magnetic reference bearing

C

Hot Springs Muni

(HSR)

3150 45 L

 AINSWORTH

 112.7 ANW 74 N42°34.15' W99°59.38'

H

COLUMBUS

122.4 D

086

248

+

H

P-00

R-000

W-000

A-000

CYR-000

CYA-000

(MU) D-000

SPECIAL USE AIRSPACE

WALL 1

MOA

WALL 2

MOA

Exclusion area and note

Line delimits 

internal separation 

of same special 

use area or 

exclusion areas

I

IR-15-17

 AINSWORTH

 114.0 MAI 87 

N30°47.17' W85°07.47'

H

GAINESVILLE

122.4

Figure 2-26. Victor airways.

Figure 2-27. LF/MF airways.
2-16

Figure 2-28. Low altitude RNAV routes.

Figure 2-29. Low altitude RNAV route data.

T270

70

5000G

*5400

6000G

087

67

268 088

NGOZI

GRANT

269

T270

Waypoint

Magnetic reference bearing

Figure 2-30. Joint Victor/RNAV airway.

T228 V333

JES VAL BILLY TOMMY YATES

333 332 4400

7000G

10000

7000G

*6700

10000

8000G

*6700

10 10 49 40 109

•	 Identification boxes

•	 Mileages

•	 Waypoints

•	 Waypoint names

•	 Magnetic reference bearings

•	 MEAs

Magnetic reference bearings are shown originating from a 

waypoint, fix/reporting point, or NAVAID. A GNNS MEA for 

each segment is established to ensure obstacle clearance 

and communications reception. All MEAs are identified 

with a “G” suffix. [Figure 2-29]

Joint Victor/RNAV routes are depicted using black for 

the victor airways and blue for the RNAV routes, and the 

identification boxes for each are shown adjacent to one 

another. Magnetic reference bearings are not shown. MEAs 

are stacked in pairs or in two separate columns, GNSS and 

Victor. On joint routes, RNAV specific information is printed 

in blue. [Figure 2-30]
2-17

Figure 2-32. Navigation reference system (NRS) waypoints. W122° N40° 264 247

J189

J501

 RED BLUFF

 115.7 RBA 104 

122.4

H

Chico Muni

(CIC)

KO63E

KO60E

Redding Muni

(RDD)

Red Bluff Muni

(RBL)

Q5

Q3

Q1

135

203

MEA-22000

MEA-24000D

1300-06002

MEA CAP 1300-06002

MEA-24000D

1300-06002

MEA-26000D

110

134

Waypoint

Waypoint

162

144

010

352

330

RANCHO MURIETA

N40°05.93'

W122°14.18'

Figure 2-31. IFR en route high altitude chart.

N39'

111

83

34

40

27

31

92

70

142

244

112

J26

J26

J96

133

J87

21

51

J87

J24

55

J80

68

002

DRIVL

SAAGS

CORIM

HUGIN

FONIX

KIDER

 BRAYMER

 111.2 BQS[L] 49 

 NAPOLEON

 114.0 ANX[L] 87 

 ROBINSON

 108.2 RBA[L] 19 

COLUMBIA 122.6

115.9 SUM 106

ST JOSEPH

Rosaceach Mem

[STJ]

Sherman AAF

(FLV)

Lawrence Muni

(LWC)

TOPEKA

Philip Billard Muni

(TOP)

Kansas City Intl

(MCI)

KANSAS CITY

Charles B Wheeler

Downtown

(MKC)

MOSBY

Midwest National

Air Control

(GPH)

Marshall Mem Muni

(MHI)

AGENT

237

266 66 257

231

145

333

016

057

075

091°

190°

060°

21

35

085

080

263

260

219

57

38

Figure 2-33. High altitude jet routes.

252

203

156

159

132

(OFTEC) SAKES

Green River Muni

(U34)

Honksville

MOAB

Camyonland’s Fld

(CNY)

MEA-33000

J196

J196

J80

71

055

073 254

J80

J28

J28

CEDAR CITY 111.2 

153

50

X

R-6413

IFR En Route High Altitude Chart 

En route high altitude charts provide aeronautical 

information for navigation under IFR conditions at and 

above FL180 . [Figure 2-31] High altitude charts include 

the following information:

•	 Jet route structure

•	 RNAV Q-routes

•	 VHF radio aidsto navigation (frequency, ID, channel,

geographic coordinates)

•	 Selected airports

•	 Reporting points

•	 Navigation reference system (NRS) waypoints

[Figure 2-32]

Jet routes are depicted in black with a “J” identifier followed 

by the route number (e.g., “J12”) and are based on VOR or 

VORTAC NAVAIDs. [Figure 2-33] RNAV “Q” Route MEAs are 

shown when other than 18,000 feet. [Figure 2-34] MEAs 

for GNSS RNAV aircraft are identified with a “G” suffix. 

MEAs for DME/DME/IRU RNAV aircraft do not have a “G” 

suffix. All RNAV routes and associated data is charted in 

aeronautical blue and magnetic reference bearings are 
2-18

Figure 2-35. Joint jet/RNAV routes.

J12 Q7

MEA - 27000

MEA - 23000G

300

JointJet/RNAV Route

Figure 2-34. MEAs on RNAV (Q) routes.

Q5

Q3

Q1

MEA-24000D

1300-06002

1300-06002

1300-06002

MEA-24000D

MEA-26000D

69

69

69

115.9 SUM 106 150

149

113

ENVIE

FINER

HOMEG

OTTOO

W123°

150

343 163

163

162

343

343

shown originating from a waypoint, fix/reporting point, 

or NAVAID. When joint Jet/RNAV routes are depicted, the 

route identification boxes are located adjacent to each 

other with the route charted in black. [Figure 2-35] With 

the exception of “Q” routes in the Gulf of Mexico, GNSS or 

DME/DME/IRU RNAV equipment is required along with 

radar monitoring capabilities. For aircraft that have DME/

DME/IRU RNAV equipment, refer to the A/FD for specific

DME information.

VHF Airways

Victor airways are a system of established routes that 

run along specified VOR radials, from one VOR station to 

another. The purpose is to make flight planning easier 

and they help ATC to organize and regulate the air traffic 

flow. Almost all commercial flights are routed along these 

airways but they are available for use by any pilot provided 

that the proper altitudes are employed.

Victor Airway Navigation Procedures

The procedure for getting established on a victor airway 

is to either fly directly to a nearby VOR or to intercept 

an airway radial along the route of flight. Once the pilot 

is established on an airway, it is important to follow the 

procedures and guidelines put in place to ensure air traffic 

separation and optimal safety on the airway. When using 

victor airways for navigation, procedures do not allow the 

pilot to jump from one VOR to another, but must navigate 

from one to the next by using the alternating outbound/

inbound procedure of linking VORs. For example, when 

departing from Zanesville VOR on V-214, the pilot selects 

the 090° radial with a FROM indication on the course 

deviation indicator (CDI) and should correct as necessary 

to continuously maintain track on the centerline of the 

airway. [Figure 2-36] The pilot should continue on this 

course until it is time to change over to the inbound course 

to the Bellaire VOR. 

LF/MF Airways

The basic LF/MF airway width is 4.34 nautical miles (NM) 

on each side of the centerline; the width expands by five 

degrees when the distance from the facility providing 

course guidance is greater than 49.66 NM. [Figure 2-37]

En Route Obstacle Clearance Areas

All published routes in the NAS are based on specific 

obstacle clearance criteria. An understanding of en route 

obstacle clearance areas helps with SA and may help avoid 

controlled flight into terrain (CFIT). Obstacle clearance 

areas for the en route phase of flight are identified as 

primary, secondary, and turning areas.

The primary and secondary area obstacle clearance 

criteria, airway and route widths, and the ATC separation 

procedures for en route segments are a function of 

safety and practicality in flight procedures. These flight 

procedures are dependent upon the pilot, the aircraft, and 

the navigation system being used, resulting in a total VOR 

system accuracy factor along with an associated probability 
2-19

Figure 2-36. Zanesville VOR/Victor Airway 214.

43

50 29

3000

3000

17

SABGE

090°

109

334

12 9

12

147

347

183

LORES N40°

276

15

15

209

22 2500

3000

ZANDR

MUNCE

HISOM 5

V214

V117

V117

263

272

224

158

330

300

59-115

Barnesville Brodfield

(6G5)

1312 4D L

[2P7]

1187 L*28

Cambridge Muni

(CDI)

 799 43 L

Zoneville Muni

(ZZV)

 900 50 L

 ZANESVILLE

 111.4 ZZV 51 N42°34.15' W99°59.38'

A

CLEVELAND

122.5 122.2 122.1R

 BELLAIRE

 117.1AIR 118 N40°31.00' W99°49.04'

A

CLEVELAND

122.1R

CLEVELAND Bolonl 120.4 257.975

21

33

34

17

Figure 2-37. LF/MR airway width.

5°

NBD

4.34 NM

49.66 NM

5° NBD

5°

5°

Figure 2-38. Primary obstacle clearance area.

4.5°

4.5°

4.5°

4.5°

51

51

4 NM

4 NM

Primary obstacle clearance area

V214

factor. The pilot/aircraft information component of these 

criteria includes pilot ability to track the radial and the flight 

track resulting from turns at various speeds and altitudes 

under different wind conditions. The navigation system 

information includes navigation facility radial alignment 

displacement, transmitter monitor tolerance, and receiver 

accuracy. All of these factors were considered during 

development of en route criteria. From this analysis, the 

computations resulted in a total system accuracy of ±4.5° 

95 percent of the time and ±6.7° 99 percent of the time. 

The 4.5° figure became the basis for primary area obstacle 

clearance criteria, airway and route widths, and the ATC 

separation procedures. The 6.7° value provides secondary 

obstacle clearance area dimensions.

Primary and Secondary En Route Obstacle 

Clearance Areas

The primary obstacle clearance area has a protected width 

of 8 NM with 4 NM on each side of the centerline. The 

primary area has widths of route protection based upon 

system accuracy of a ±4.5° angle from the NAVAID. These

4.5° lines extend out from the NAVAID and intersect the 

boundaries of the primary area at a point approximately

51 NM from the NAVAID. Ideally, the 51 NM point is where 

pilots would change over from navigating away from the

facility, to navigating toward the next facility, although this 

ideal is rarely achieved. [Figure 2-38]

If the distance from the NAVAID to the change-over point 

(COP) is more than 51 NM, the outer boundary of the 

primary area extends beyond the 4 NM width along the 
2-20

Figure 2-40. Secondary obstacle clearance area.

6.7°

6.7°

6.7°

6.7°

51

51

4 NM

4 NM

2 NM

Secondary obstacle clearance area

V214

2 NM

Figure 2-39. Non-mountainous obstacle clearance in the primary 

area.

Primary en route obstacle clearance area

1,000 feet above highest obstacle

Figure 2-41. Primary and secondary obstacle clearance area.

Primary Area

Secondary Area

500 feet

Total width of secondary area

Nonmountainous Mountainous

4.5° line when the COP is at midpoint. This means the 

primary area, along with its obstacle clearance criteria, is 

extended out into what would have been the secondary 

area. Additional differences in the obstacle clearance area 

result in the case of the effect of an offset COP or dogleg 

segment. For protected en route areas, the minimum 

obstacle clearance in the primary area, not designated as 

mountainous under 14 CFR Part 95—IFR altitude, is 1,000 

feet over the highest obstacle. [Figure 2-39] The secondary 

obstacle clearance area extends along a line 2 NM on each 

side of the primary area. Navigation system accuracy in 

the secondary area has widths of route protection of a 

±6.7° angle from the NAVAID. These 6.7° lines intersect the 

outer boundaries of the secondary areas at the same point 

as primary lines, 51 NM from the NAVAID. If the distance 

from the NAVAID to the COP is more than 51 NM, the 

secondary area extends along the 6.7° line when the COP 

is at mid-point. [Figure 2-40] In all areas, mountainous and 

non-mountainous, obstacles that are located in secondary 

areas are considered as obstacles to air navigation if they 

extend above the secondary obstacle clearance plane. 

This plane begins at a point 500 feet above the obstacles 

(natural or man-made) upon which the primary obstacle 

clearance area is based, and slants upward at an angle that 

causes it to intersect the outer edge of the secondary area 

at a point 500 feet higher. [Figure 2-41]

Changeover Points

When flying airways, pilots normally change frequencies 

midway between NAVAIDs, although there are times 

when this is not practical. If the navigation signals cannot 

be received from the second VOR at the midpoint of the 

route, a COP is depicted and shows the distance in NM to 

each NAVAID. [Figure 2-42] COPs indicate the point where a 

frequency change is necessary to receive course guidance 

from the facility ahead of the aircraft instead of the one 

behind. These COPs divide an airway or route segment and 

ensure continuous reception of navigation signals at the 

prescribed minimum en route IFR altitude. They also ensure 

that other aircraft operating within the same portion of 
2-21

Figure 2-42. Changeover points.

13,000 ft

13,000

22

45

V344

Figure 2-43. Changeover point effect on long airway or route segment.

4.5°

6.7° 4.5°

70 6.7°

70

4 NM

4 NM

Secondary areas

Primary areas

V214

2 NM

2 NM

Flare

Flare

an airway or route segment receive consistent azimuth 

signals from the same navigation facilities regardless of 

the direction of flight.

Where signal coverage from two VORs overlaps at the MEA, 

the COP normally is designated at the midpoint. Where 

radio frequency interference or other navigation signal 

problems exist, the COP is placed at the optimum location, 

taking into consideration the signal strength, alignment 

error, or any other known condition that affects reception. 

The COP has an effect on the primary and secondary 

obstacle clearance areas. On long airway or route segments, 

if the distance between two facilities is over 102 NM and the 

COP is placed at the midpoint, the system accuracy lines 

extend beyond the minimum widths of 8 and 12 NM, and a 

flare or spreading outward results at the COP. [Figure 2-43] 

Offset COP and dogleg segments on airways or routes can 

also result in a flare at the COP.

Direct Route Flights

Direct route flights are flights that are not flown on the 

radials or courses of established airways or routes. Direct 

route flights must be defined by indicating the radio fixes 

over which the flight passes. Fixes selected to define the 

route should be those over which the position of the aircraft 

can be accurately determined. Such fixes automatically 

become compulsory reporting points for the flight, unless 

advised otherwise by ATC. Only those NAVAIDs established 

for use in a particular structure (i.e., in the low or high 

structures) may be used to define the en route phase of a 

direct flight within that altitude structure. 

Figure 2-44 shows a straight line on a magnetic course 

from SCRAN intersection of 270° direct to the Fort Smith 
2-22

Figure 2-44. Direct route navigation.

NOT FOR NAVIGATION

 FOR NAVIGATIO

Regional Airport in Arkansas that passes just north of 

restricted areas R-2401A and B and R-2402. Since the airport 

and the restricted areas are precisely plotted, there is an 

assurance that you will stay north of the restricted areas. 

From a practical standpoint, it might be better to fly direct 

to the Wizer NDB. This route goes even further north of the 

restricted areas and places you over the final approach fix 

to Runway 25 at Fort Smith.

The azimuth feature of VOR aids and the azimuth and 

distance (DME) features of VORTAC and TACAN aids are 

assigned certain frequency protected areas of airspace that 

are intended for application to established airway and route 

use and to provide guidance for planning flights outside 

of established airways or routes. These areas of airspace 

are expressed in terms of cylindrical service volumes of 

specified dimensions called class limits or categories.

An operational service volume has been established 

for each class in which adequate signal coverage and 

frequency protection can be assured. To facilitate use 

of VOR, VORTAC, or TACAN aids, consistent with their 

operational service volume limits, pilot use of such aids 

for defining a direct route of flight in controlled airspace 

should not exceed the following:

1. Operations above FL 450—use NAVAIDs not more 

than 200 NM apart. These aids are depicted on en 

route high altitude charts. 

2. Operation off established routes from 18,000 feet 

MSL to FL 450—use NAVAIDs not more than 260 

NM apart. These aids are depicted on en route high 

altitude charts. 

3. Operation off established airways below 18,000 feet 

MSL—use NAVAIDs not more than 80 NM apart. 

These aids are depicted on en route low altitude charts. 

4. Operation off established airways between 14,500 

feet MSL and 17,999 feet MSL in the conterminous 

United States—(H) facilities not more than 200NM 

apart may be used.

Increasing use of self-contained airborne navigational 

systems that do not rely on the VOR/VORTAC/TACAN 
2-23

system has resulted in pilot requests for direct routes that 

exceed NAVAID service volume limits. These direct route 

requests are approved only in a radar environment with 

approval based on pilot responsibility for navigation on the 

authorized direct route. Radar flight following is provided 

by ATC for ATC purposes. At times, ATC initiates a direct 

route in a radar environment that exceeds NAVAID service 

volume limits. In such cases, ATC provides radar monitoring 

and navigational assistance as necessary.

When filing for a direct route flight, airway or jet route 

numbers, appropriate to the stratum in which operation 

is conducted, may also be included to describe portions 

of the route to be flown. The following is an example of 

how a direct route flight would be written.

MDW V262 BDF V10 BRL STJ SLN GCK

Spelled out: from Chicago Midway Airport via Victor 

262 to Bradford, Victor 10 to Burlington, Iowa, direct St. 

Joseph, Missouri, direct Salina, Kansas, direct Garden 

City, Kansas.

NOTE: When route of flight is described by radio fixes, 

the pilot is expected to fly a direct course between the 

points named.

Pilots should keep in mind that they are responsible 

for adhering to obstruction clearance requirements 

on those segments of direct routes that are outside of 

controlled airspace. The MEAs and other altitudes shown 

on low altitude IFR en route charts pertain to those route 

segments within controlled airspace, and those altitudes 

may not meet obstruction clearance criteria when 

operating off those routes.

Published RNAV Routes

Published RNAV routes are fixed, permanent routes that 

can be flight planned and flown by aircraft with RNAV 

capability. These are being expanded worldwide as 

new RNAV routes are developed, and existing charted, 

conventional routes are being designated for RNAV use. It 

is important to be alert to the rapidly changing application 

of RNAV techniques being applied to conventional en 

route airways. Published RNAV routes may potentially be 

found on any en route chart. The published RNAV route 

designation may be obvious, or, on the other hand, RNAV 

route designations may be less obvious, as in the case 

where a published route shares a common flight track with 

a conventional airway.

NOTE: The use of RNAV is dynamic and rapidly changing, 

therefore, en route charts are continuously being updated 

for information changes, and you may find some differences 

between charts.

Basic designators for air traffic service (ATS) routes and 

their use in voice communications have been established. 

One of the main purposes of a system of route designators 

is to allow both pilots and ATC to make unambiguous 

reference to RNAV airways and routes. Basic designators 

for ATS routes consist of a maximum of five, and in no 

case to exceed six, alpha/numeric characters in order to be 

usable by both ground and airborne automation systems. 

The designator indicates the type of the route, such as 

high/low altitude, specific airborne navigation equipment 

requirements, such as RNAV, and the aircraft type using the 

route primarily and exclusively. The basic route designator 

consists of one or two letter(s) followed by a number from 

1 to 999.

Composition of Designators

The prefix letters that pertain specifically to RNAV 

designations are included in the following list:

1. The basic designator consists of one letter of the 

alphabet followed by a number from 1 to 999. The 

letters may be:

a. A, B, G, R—for routes that form part of the 

regional networks of ATS route and are not 

RNAV routes;

b. L, M, N, P—for RNAV routes that form part of 

the regional networks of ATS routes;

c. H, J, V, W—for routes that do not form part of 

the regional networks of ATS routes and are not 

RNAV routes;

d. Q, T, Y, Z—for RNAV routes that do not form 

part of the regional networks of ATS routes.

2. Where applicable, one supplementary letter must be 

added as a prefix to the basic designator as follows:

a. K—to indicate a low level route established for 

use primarily by helicopters;

b. U—to indicate that the route or portion thereof 

is established in the upper airspace;

c. S—to indicate a route established exclusively for 

use by supersonic airplanes during acceleration/

deceleration and while in supersonic flight.

3. Where applicable, a supplementary letter may be 

added after the basic designator of the ATS route as 

a suffix as follows:

a. F—to indicate that on the route or portion thereof 

advisory service only is provided;
2-24

Figure 2-45. Published RNAV jet routes.

NOT FOR NAVIGATION

N60°53.97 ́ W 151°2163 ́

114.3 ANC 221.3°-37.0

AMOTT

280

MEA-28000

J888R

J996R

J804R

61.2

61°

246 237

226°

AMOTT

37

22

10346

b. G—to indicate that on the route or portion thereof 

flight information services only is provided;

c. Y—for RNP 1 routes at and above FL 200 to 

indicate that all turns on the route between 30° 

and 90° must be made within the tolerance of a 

tangential arc between the straight leg segments 

defined with a radius of 22.5 NM;

d. Z—for RNP 1 routes at and below FL 190 to 

indicate that all turns on the route between 30° 

and 90° should be made within the tolerance 

of a tangential arc between the straight leg 

segments defined with a radius of 15 NM.

NOTE: RNAV Q-routes require en route RNAV 2, 

corresponding NAV/E2 code and PBN/C1-C4 based on 

navigation system update source.

Use of Designators in Communications

In voice communications, the basic letter of a designator 

should be spoken in accordance with the International Civil 

Aviation Organization (ICAO) spelling alphabet. Where the 

prefixes K, U, or S, previously mentioned, are used in voice 

communications, they should be pronounced as:

K—Kopter

U—Upper, as in the English language 

S—Supersonic

Where suffixes F, G, Y or Z specified in above, are used, the 

flight crew should not be required to use them in voice 

communications. Below is an example of how the letters 

and numbers are spoken. 

A11—Alpha Eleven

UR5—Upper Romeo Five

KB34—Kopter Bravo Thirty Four

UW456—Upper Whiskey Four Fifty Six

The en route chart excerpt depicts three published RNAV jet 

routes: J804R, J888R, and J996R. [Figure 2-45] The R suffix 

is a supplementary route designator denoting an RNAV 

route. The overlapping symbols for the AMOTT intersection 
2-25

and waypoint indicate that AMOTT can be identified by 

conventional navigation or by latitude and longitude 

coordinates. Although coordinates were originally included 

for aircraft equipped with an inertial navigation system 

(INS), they are now a good way to cross check between 

the coordinates on the chart and in the flight management 

system (FMS) or global positioning system (GPS) databases 

to ensure you are tracking on your intended en route 

course. The AMOTT RNAV waypoint includes bearing and 

distance from the Anchorage VORTAC.

Random RNAV Routes

Random RNAV routes are direct routes that are based on 

RNAV capability between waypoints defined in terms of 

latitude or longitude coordinates, degree-distance fixes, 

or offsets from established routes or airways at a specified 

distance and direction. Radar monitoring by ATC is required 

on all random RNAV routes. Random RNAV routes can 

only be approved in a radar environment. Factors that 

are considered by ATC when approving random RNAV 

routes include the capability to provide radar monitoring 

and compatibility with traffic volume and flow. ATC radar 

monitor each flight; however, navigation on the random 

RNAV route is the responsibility of the pilot.

Pilots flying aircraft that are equipped with approved area 

navigation equipment may file for RNAV routes throughout 

the NAS and may be filed for in accordance with the 

following procedures:

1. File airport-to-airport flight plans.

2. File the appropriate RNAV capability certification 

suffix in the flight plan.

3. Plan the random route portion of the flight plan 

to begin and end over appropriate arrival and 

departure transition fixes or appropriate NAVAIDs 

for the altitude stratum within which the flight is 

conducted. The use of normal preferred DPs and 

STAR, where established, is recommended.

4. File route structure transitions to and from the 

random route portion of the flight.

5. Define the random route by waypoints. File route 

description waypoints by using degree distance fixes 

based on navigational aids that are appropriate for 

the altitude stratum.

6. File a minimum of one route description waypoint 

for each ARTCC through whose area the random 

route is flown. These waypoints must be located 

within 200 NM of the preceding center’s boundary.

7. File an additional route description waypoint for 

each turnpoint in the route.

8. Plan additional route description waypoints as 

required to ensure accurate navigation via the filed 

route of flight. Navigation is the pilot’s responsibility 

unless ATC assistance is requested.

9. Plan the route of flight so as to avoid prohibited and 

restricted airspace by 3 NM unless permission has 

been obtained to operate in that airspace and the 

appropriate ATC facilities are advised.

NOTE: To be approved for use in the NAS, RNAV equipment 

must meet the appropriate system availability, accuracy, 

and airworthiness standards. For additional guidance on 

equipment requirements, see AC 20-130, Airworthiness 

Approval of Vertical Navigation (VNAV) Systems for use in 

the U.S. NAS and Alaska, or Advisory Circular (AC)

20-138, Airworthiness Approval of Positioning and 

Navigation Systems. For airborne navigation database, 

see AC 90-105, Approval Guidance for RNP Operations 

and Barometric Vertical Navigation in the U.S. National 

Airspace System.

Pilots flying aircraft that are equipped with latitude/

longitude coordinate navigation capability, independent 

of VOR/ TACAN references, may file for random RNAV routes 

at and above FL 390 within the conterminous United States 

using the following procedures:

1. File airport-to-airport flight plans prior to departure.

2. File the appropriate RNAV capability certification 

suffix in the flight plan.

3. Plan the random route portion of the flight to 

begin and end over published departure/arrival 

transition fixes or appropriate NAVAIDs for airports 

without published transition procedures. The use of 

preferred departure and arrival routes, such as DP 

and STAR where established, is recommended.

4. Plan the route of flight so as to avoid prohibited and 

restricted airspace by 3 NM unless permission has 

been obtained to operate in that airspace and the 

appropriate ATC facility is advised.

5. Define the route of flight after the departure fix, 

including each intermediate fix (turnpoint) and 

the arrival fix for the destination airport in terms 

of latitude/longitude coordinates plotted to the 

nearest minute or in terms of Navigation Reference 

System (NRS) waypoints. For latitude/longitude 

filing, the arrival fix must be identified by both the 

latitude/ longitude coordinates and a fix identifier 

as shown in the example below.

MIA1 SRQ2 3407/106153 3407/11546 TNP4 LAX5
2-26

Figure 2-46. Excerpt of authorized areas of en route operation.

SAMPLE NOT FOR 

ACTUAL USE

The 48 contiguous United 

States and the District of 

Columbia

Canada, excluding Canadian 

MNPS airspace and the areas 

of magnetic unreliability as 

established in the Canadian 

AIP

SPECIAL REQUIREMENTS:

Note 1 - B-737 Class II navigation operations with a single longrange system is authorized only within this area of en route 

operation.

Note 3 - Only B-747 and DC-10 operations authorized in these 

areas.

Note 1

Note 3

Authorized areas of

en route operation

Limitations, provisions,

and reference paragraphs

1Departure airport

2Departure fix

3Intermediate fix (turning point)

4Arrival fix

5Destination airport

Or:

ORD1 IOW2 KP49G3 KD34U4 KL16O5 OAL 6

MOD27 SFO8

1Departure airport

2Transition fix (pitch point)

3Minneapolis ARTCC waypoint

4Denver ARTCC waypoint

5Los Angeles ARTCC waypoint (catch point)

6Transition fix

7Arrival

8Destination airport

6. Record latitude/longitude coordinates by four 

figures describing latitude in degrees and minutes 

followed by a solidus and five figures describing 

longitude in degrees and minutes.

7. File at FL 390 or above for the random RNAV portion 

of the flight.

8. Fly all routes/route segments on Great Circle tracks.

9. Make any in-flight requests for random RNAV 

clearances or route amendments to an en route ATC 

facility.

Off-Airway Routes 

14 CFR Part 95 prescribes altitudes governing the operation 

of aircraft under IFR on Federal airways, jet routes, RNAV low 

or high altitude routes, and other direct routes for which a 

MEA is designated. In addition, it designates mountainous 

areas and COPs. Off-airway routes are established in the 

same manner and in accordance with the same criteria 

as airways and jet routes. If a pilot flies for a scheduled air 

carrier or operator for compensation or hire, any requests for 

the establishment of off-airway routes are initiated by the 

company through the principal operations inspector (POI) 

who works directly with the company and coordinates FAA 

approval. Air carrier authorized routes should be contained 

in the company’s Operations Specifications (OpSpecs) under 

the auspices of the air carrier operating certificate. [Figure 

2-46]

Off-airway routes predicated on public navigation 

facilities and wholly contained within controlled airspace 

are published as direct Part 95 routes. Off-airway routes 

predicated on privately owned navigation facilities or 

not contained wholly within controlled airspace are 

published as off-airway non- Part 95 routes. In evaluating 

the adequacy of off-airway routes, the following items are 

considered: the type of aircraft and navigation systems 

used; proximity to military bases, training areas, low level 

military routes; and the adequacy of communications 

along the route.

Commercial operators planning to fly off-airway routes 

should have specific instructions in the company’s 

OpSpecs that address en route limitations and provisions 

regarding en route authorizations to use the GPS or other 

RNAV systems in the NAS. The company’s manuals and 

checklists should include practices and procedures for 

long-range navigation and training on the use of long 

range navigation equipment. Minimum equipment lists 

(MELs) and maintenance programs must address the long 

range navigation equipment. Examples of other selected 

areas requiring specialized en route authorization include 

the following:

•	 Class I navigation in the United States Class A

airspace using area of long range navigation system.

•	 Class II navigation using multiple long range

navigation systems. 

•	 Operations in central East Pacific airspace.
2-27

Figure 2-47. Off-route obstacle clearance altitude.

NOT FOR NAVIGATION

•	 North Pacific operations.

•	 Operations within North Atlantic (NAT) minimum

navigation performance specifications (MNPS) 

airspace.

•	 Operations in areas of magnetic unreliability.

•	 NorthAtlantic operation (NAT/OPS)with two engine

airplanes under 14 CFR Part 121.

•	 Extended range operations (ER-OPS) with two

engine airplanes under 14 CFR Part 121.

•	 Special fuel reserves in international operations.

•	 Planned in-flight re-dispatch or re-release en route.

•	 Extended over water operations using a single longrange communication system.

•	 Operationsin reduced verticalseparation minimum

(RVSM) airspace.

Off-Route Obstruction Clearance Altitude

An off-route obstruction clearance altitude (OROCA) is 

an off-route altitude that provides obstruction clearance 

with a 1,000 foot buffer in non-mountainous terrain areas 

and a 2,000 foot buffer in designated mountainous areas 

within the United States. This altitude may not provide 

signal coverage from ground-based NAVAIDs, ATC radar, 

or communications coverage. OROCAs are intended 

primarily as a pilot tool for emergencies and SA. OROCAs 

depicted on en route charts do not provide the pilot with 

an acceptable altitude for terrain and obstruction clearance 

for the purposes of off-route, random RNAV direct flights 

in either controlled or uncontrolled airspace. OROCAs 

are not subject to the same scrutiny as MEAs, minimum 

vectoring altitude (MVAs), MOCAs, and other minimum IFR 

altitudes. Since they do not undergo the same obstruction 

evaluation, airport airspace analysis procedures, or 

flight inspection, they cannot provide the same level of 

confidence as the other minimum IFR altitudes.
2-28

Figure 2-48. Random RNAV route.

NOT FOR NAVIGATION

60 nm

30 nm

TBC

PGA

GCN

134T/131kts

COM

127.550

134.650

WPT

MIRAJ

DTK

259°M

TRK

259°M

DIS

193

VLOC

113.50

116.90

n

m

ENR

VLOC MSG

TBC

PGA

100 -1

no map

n

m

NAV

FMS map mode navigation display

GPS

FMS

When departing an airport VFR intending to or needing to 

obtain an IFR clearance en route, you must be aware of the 

position of your aircraft relative to terrain and obstructions. 

When accepting a clearance below the MEA, MIA, MVA, 

or the OROCA, you are responsible for your own terrain/ 

obstruction clearance until reaching the MEA, MIA, or MVA.

If unable to visually maintain terrain/obstruction clearance, 

pilots should advise ATC and state intentions of the flight. 

[Figure 2-47]

For all random RNAV flights, there needs to be at least one 

waypoint in each ARTCC area through which you intend 

to fly. One of the biggest problems in creating an RNAV 

direct route is determining if the route goes through special 

use airspace. For most direct routes, the chances of going 

through prohibited, restricted, or special use airspace 

are good. In the United States, all direct routes should be 

planned to avoid prohibited or restricted airspace by at 

least 3 NM. If a bend in a direct route is required to avoid 

special use airspace, the turning point needs to be part 

of the flight plan. Two of the most prominent long range 

navigation systems today include FMS with integrated GPS 
2-29

and stand-alone GPS. The following example is a simplified 

overview showing how the RNAV systems might be used 

to fly a random RNAV route.

Shown in Figure 2-48, the aircraft is northeast of Tuba City 

VORTAC at FL 200 using RNAV (showing both GPS and 

FMS), RNAV direct on a southwesterly heading to Lindbergh 

Regional Airport in Winslow. As the pilot is monitoring his 

or her position and cross-checking the avionics against the 

high altitude en route chart, he or she receives a company 

message instructing to divert to Las Vegas, requiring a 

change in the flight plan as highlighted on the depicted 

chart excerpt.

During the flight deck review of the high and low altitude 

en route charts, the pilot determines that the best course 

of action is to fly direct to the MIRAJ waypoint, 28 DME 

northeast of the Las Vegas VORTAC on the 045° radial. This 

places the aircraft 193 NM out on a 259° magnetic course 

inbound, and may help to avoid diverting north, allowing to 

bypass the more distant originating and intermediate fixes 

feeding into Las Vegas. The pilot requests an RNAV random 

route clearance direct MIRAJ to expedite the flight. Denver 

Center comes back with the following amended flight plan 

and initial clearance into Las Vegas:

“Marathon five sixty four, turn right heading two six zero, 

descend and maintain one six thousand, cleared present 

position direct MIRAJ.”

The latitude and longitude coordinates of the aircraft’s 

present position on the high altitude chart is N36 19.10 

and W110 40.24 as the course is changed. Notice the GPS 

moving map (upper left), the FMS control display unit 

(below the GPS), and FMS map mode navigation displays 

(to the right of the GPS) as the flight is rerouted to Las Vegas. 

For SA, the pilot makes note that the altitude is well above 

any of the OROCAs on the direct route as the flight arrives 

in the Las Vegas area using the low altitude chart.

Monitoring of Navigation Facilities

VOR, VORTAC, and instrument landing system (ILS) facilities, 

as well as most NDBs and marker beacons installed by the 

FAA, are provided with an internal monitoring feature. 

Internal monitoring is provided at the facility through 

the use of equipment that causes a facility shutdown if 

performance deteriorates below established tolerances. 

A remote status indicator also may be provided through 

the use of a signal- sampling receiver, microwave link, or 

telephone circuit. Older FAA NDBs and some non-Federal 

NDBs do not have the internal feature, and monitoring is 

accomplished by manually checking the operation at least 

once each hour. FAA facilities, such as automated flight 

service stations (AFSSs) and ARTCCs/sectors, are usually 

the control point for NAVAID facility status. Pilots can query 

the appropriate FAA facility if they have questions in flight 

regarding NAVAID status, in addition to checking NOTAMs 

prior to flight, since NAVAIDs and associated monitoring 

equipment are continuously changing.

Navigational Gaps

A navigational course guidance gap, referred to as an 

MEA gap, describes a distance along an airway or route 

segment where a gap in navigational signal coverage 

exists. The navigational gap may not exceed a specific 

distance that varies directly with altitude, from 0 NM at 

sea level to 65 NM at 45,000 feet MSL and not more than 

one gap may exist in the airspace structure for the airway 

or route segment. Additionally, a gap usually does not 

occur at any airway or route turning point. To help ensure 

the maximum amount of continuous positive course 

guidance available when flying, there are established 

en route criteria for both straight and turning segments. 

Where large gaps exist that require altitude changes, MEA 

“steps” may be established at increments of not less than 

2,000 feet below 18,000 feet MSL, or not less than 4,000 

feet at 18,000 MSL and above, provided that a total gap 

does not exist for the entire segment within the airspace 

structure. MEA steps are limited to one step between any 

two facilities to eliminate continuous or repeated changes 

of altitude in problem areas. The allowable navigational 

gaps pilots can expect to see are determined, in part, by 

reference to the graph depicted in Figure 2-49. Notice 

the en route chart excerpt depicting that the MEA is 

established with a gap in navigation signal coverage 

northwest of the Carbon VOR/DME on V134 . At the MEA 

of 13,000, the allowable navigation course guidance gap 

is approximately 18.5 NM, as depicted in Figure 2-49. 

The navigation gap area is not identified on the chart 

by distances from the navigation facilities. Proper flight 

planning will help pilots prepare for MEA gaps by insuring 

that appropriate maps are available as they may need 

to dead reckon through the gap. Calculating the ground 

track (with adjustments for winds) before and after the 

gap will also help to stay on course when navigational 

course guidance is not available.

NAVAID Accuracy Check

The CFRs and good judgment dictate that the equipment 

of aircraft flying under IFR be within a specified tolerance 

before taking off. When approved procedures are available, 

they should be used for all equipment inspections.

VOR Accuracy

VOR accuracy can be checked by using any of the following 

methods: VOR test facility signal (VOT), VOR checkpoint 

signs, dual VOR check, or airborne VOR check.
2-30

Figure 2-50. VOR test facilities (VOT) frequencies.

VOR test facilities (VOT)

Facility Name .............................. Type VOT

(Airport Name) ...........Frequency Facility Remarks

Bradlay Intl .................... 111.40 G 

Bridgeport ..................... 109.25 G 

Groton ........................... 110.25 G 

Hartford ......................... 108.20 G 

Figure 2-49. Navigational course guidance gaps.

Sample: Enter with MEA of 13,000 feet. Read allowable gap 18.5 NM.

60

55

50

45

40

35

30

25

20

15

10

5

0

5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95

Allowable navigation course guidance gap (NM)

NOT FOR

 NAVIGATION

MEA of airway or route segment (thousands of feet)

Figure 2-51. VOR checkpoint signs.

VOR 116.4

147° 4.1 NM

DME and VOR check radial

VOT

The VOT is an approved test signal and is located on an 

airport. This enables the pilot to check the VOR accuracy 

from the flight deck before takeoff. Listed below are the 

steps used for a VOT:

1. Tune the VOR receiver to the VOT frequency. VOT 

frequencies can be found in the A/FD. [Figure 2-50] 

These frequencies are coded with a series of Morse 

code dots or a continuous 1020-cycle tone.

2. On the VOR, set the course selector to 0° and the 

track bar (TB) indicator should read center. The TOFROM indicator should read FROM.

3. Set the course selector to 180° and the TO-FROM 

indicator should read TO and the TB should then be 

centered.
2-31

Figure 2-52. Instrument panel with dual VORs.

NOTE: Determining the exact error in the receiver is done 

by turning the track selector until the TB is centered and 

noting the degrees difference between 180° or 0°. The 

maximum bearing error with the VOT system check is plus 

or minus 4° and apparent errors greater than 4° indicate 

that the VOR receiver is beyond acceptable tolerance.

VOR Checkpoint Signs

Many aerodromes have VOR checkpoint signs that are 

located beside the taxiways. [Figure 2-51] These signs 

indicate the exact point on the aerodrome that there is 

sufficient signal strength from a VOR to check the aircraft’s 

VOR receiver against the radial designated on the sign. 

Listed below are the steps to use at a VOR checkpoint:

1. Tune the proper VOR frequency.

2. Identify the VOR frequency.

3. Set the published radial on the course deviation 

indicator (CDI).

4. Confirm that the TB is centered.

5. Check the needle sensitivity by changing the 

omnibearing select (OBS) 10° each way.

6. Set the reciprocal of the radial and check the TOFROM flag change.

7. The maximum permissible difference between aircraft 

equipment and the designated radial is 4° and 0.5 NM 

of the posted distance. 

Dual VOR Check

If a VOT or VOR checkpoint is not available and the aircraft is 

equipped with dual VORs, the equipment may be checked

against one another by tuning both sets to the VOR facility 

at the same time and noting the indicated bearings to that 

station. [Figure 2-52] A difference greater than 4° between 

the two VORs indicates that one of the receivers may be 

out of tolerance.

Airborne VOR Check

VOR equipment can also be checked for accuracy while in 

flight by flying over a fix or landmark located on a published 

radial and noting the indicated radial. Variances of more 

than 6° from the published radial should be considered out 

of tolerance and not be used for IFR navigation.

NDB Accuracy Check

The pilot must identify an NDB before using it for 

navigation, and continuously monitor it while using it 

for an instrument approach. The lack of an IDENT may 

indicate that the NDB is out of service, even though it may 
2-32

Figure 2-53. Fly-by and fly-over waypoints.

Fly-by waypoint

Fly-over waypoint

Alpha

Bravo

Bravo

Alpha

still be transmitting (for instance for maintenance or test 

purposes). If an incorrect IDENT is heard, then the NDB 

should not be used.

RNAV Accuracy Check

RNAV accuracy checks may differ depending on the different 

type of equipment and manufacturer. When available, all 

written procedures should be followed. Below is a list of 

generic checks that should be used when checking the 

accuracy of the system prior to flight. 

1. System initialization—pilots should confirm that 

the navigation database is current and verify that the 

aircrafts present position has been entered correctly. 

2. Active flight plan check—the active flight plan should 

be checked by comparing the aeronautical charts, 

departure and arrival procedures, and other applicable 

documents with the map display.

3. Prior to takeoff—ensure that the RNAV system is 

available. If possible, check to see that the system is 

updating when aircraft position is changing.

NOTE: While in flight, continue to verify system accuracy 

by displaying bearing/range to a VOR/DME on the RNAV 

system and compare it to the actual RMI reading of that 

particular NAVAID.

Waypoints

Waypoints are predetermined geographical locations that 

are defined in terms of latitude/longitude coordinates or 

fixes, used to define an RNAV route or the flight path of 

an aircraft employing RNAV. Waypoints may be a simple 

named point in space or may be associated with existing 

NAVAIDs, intersections, or fixes. A waypoint is most often 

used to indicate a change in direction, speed, or altitude 

along the desired path. Aviation RNAV procedures make 

use of both fly-over and fly-by waypoints. A fly-over 

waypoint is a waypoint that must be crossed vertically by 

an aircraft. A fly-by waypoint is a waypoint that marks the 

intersection of two straight paths, with the transition from 

one path to another being made by the aircraft using a 

precisely calculated turn that flies by but does not vertically 

cross the waypoint. [Figure 2-53]

User-Defined Waypoints

Pilots typically create user-defined waypoints for use in 

their own random RNAV direct navigation. They are newly 

established, unpublished airspace fixes that are designated 

geographic locations/positions that help provide positive 

course guidance for navigation and a means of checking 

progress on a flight. They may or may not be actually 

plotted by the pilot on en route charts, but would normally 

be communicated to ATC in terms of bearing and distance 

or latitude/longitude. An example of user-defined 

waypoints typically includes those generated by various 

means including keyboard input, and even electronic map 

mode functions used to establish waypoints with a cursor 

on the display. 

Another example is an offset phantom waypoint, which is 

a point-in-space formed by a bearing and distance from 

NAVAIDs, such as VORTACs and tactical air navigation 

(TACAN) stations, using a variety of navigation systems. 

When specifying unpublished waypoints in a flight plan, 

they can be communicated using the frequency/bearing/

distance format or latitude and longitude, and they 

automatically become compulsory reporting points unless 

otherwise advised by ATC. All airplanes with latitude and 

longitude navigation systems flying above FL 390 must use 

latitude and longitude to define turning points.

Floating Waypoints

Floating waypoints, or reporting points, represent 

airspace fixes at a point in space not directly associated 

with a conventional airway. In many cases, they may be 

established for such purposes as ATC metering fixes, 

holding points, RNAV-direct routing, gateway waypoints, 

STAR origination points leaving the en route structure, 

and SID terminating points joining the en route structure. 

In the top example of Figure 2-54, a low altitude en 

route chart depicts three floating waypoints that have 

been highlighted: SCORR, FILUP, and CHOOT. Notice that 

waypoints are named with five-letter identifiers that are 

unique and pronounceable. Pilots must be careful of 
2-33

Figure 2-54. Floating waypoints.

similar waypoint names. Notice on the high altitude en 

route chart excerpt in the bottom example, the similar 

sounding and spelled floating waypoint named SCOOR, 

rather than SCORR. This emphasizes the importance 

of correctly entering waypoints into database-driven 

navigation systems. One waypoint character incorrectly 

entered into your navigation system could adversely affect 

your flight. The SCOOR floating reporting point also is 

depicted on a Severe Weather Avoidance Plan (SWAP) en 

route chart. These waypoints and SWAP routes assist pilots 

and controllers when severe weather affects the East Coast.

Computer Navigation Performance

An integral part of RNAV using en route charts typically 

involves the use of airborne navigation databases. 

Because GPS receivers are basically “to-to” navigators, 

they must always be navigating to a defined point. On 

overlay approaches, if no pronounceable five-character 

name is published for an approach waypoint or fix, it has 

been given a database identifier consisting of letters and 

numbers. These points appear in the list of waypoints in the 

approach procedure database, but may not appear on the 

approach chart. A point used for the purpose of defining 

the navigation track for an airborne computer system (i.e., 

GPS or FMS) is called a Computer Navigation Fix (CNF). CNFs 

include unnamed DME fixes, beginning and ending points 

of DME arcs, and sensor final approach fixes (FAFs) on some 

GPS overlay approaches.

To aid in the approach chart/database correlation process, 

the FAA has begun a program to assign five-letter names 

to CNFs and to chart CNFs on various National Oceanic 

Service aeronautical products. [Figure 2-55] These CNFs 

are not to be used for any ATC application, such as holding 

for which the fix has not already been assessed. CNFs are 

charted to distinguish them from conventional reporting 
2-34

Figure 2-56. U.S. standard RNP levels.

0.1 to 1.0 

0.3 to 1.0 

1 

2 

RNP AR Approach Segments 

RNP Approach Segments 

Terminal and En Route 

En Route 

0.1 to 1.0 

0.3 to 1.0 

1.0 

2.0 

RNP Level Typical Application Primary Route Width (NM) - Centerline to Boundary

Figure 2-55. Computer navigation fix.

NOT FOR NAVIGATION

points, fixes, intersections, and waypoints. A CNF name is 

enclosed in parenthesis, e.g., (MABEE) and is placed next 

to the CNF it defines. If the CNF is not at an existing point 

defined by means such as crossing radials or radial/DME, 

the point is indicated by an X. The CNF name is not used in 

filing a flight plan or in aircraft/ATC communications. Use 

current phraseology (e.g., facility name, radial, distance) to 

describe these fixes.

Many of the RNAV systems available today make it all too 

easy to forget that en route charts are still required and 

necessary for flight. As important as databases are, they 

really are onboard the airplane to provide navigation 

guidance and SA; they are not intended as a substitute 

for paper charts. When flying with GPS, FMS, or planning 

a flight with a computer, it is critical to understand the 

limitations of the system you are using, for example, 

incomplete information, unloadable procedures, complex 

procedures, and database storage limitations.

Required Navigation Performance

Required navigation performance (RNP) is RNAV with 

onboard navigation monitoring and alerting. RNP is also 

a statement of navigation performance necessary for 

operation within a defined airspace. A critical component 

of RNP is the ability of the aircraft navigation system to 

monitor its achieved navigation performance, and to 

identify for the pilot whether the operational requirement 

is, or is not being met during an operation. This onboard 

performance monitoring and alerting capability, 

therefore, allows a lessened reliance on ATC intervention 

(via radar monitoring, automatic dependent surveillancebroadcast (ADS-B), multilateration, communications), 

and/or route separation to achieve the overall safety of 

the operation. RNP capability of the aircraft is a major 

component in determining the separation criteria to 

ensure that the overall containment of the operation is 

met.
2-35

The RNP capability of an aircraft varies depending upon 

the aircraft equipment and the navigation infrastructure. 

For example, an aircraft may be equipped and certified 

for RNP 1.0, but may not be capable of RNP 1.0 operations 

due to limited NAVAID coverage.

RNP Levels

An RNP level or type is applicable to a selected airspace, 

route, or procedure. As defined in the Pilot/Controller 

Glossary, the RNP level or type is a value typically expressed 

as a distance in nautical miles from the intended centerline 

of a procedure, route, or path. RNP applications also 

account for potential errors at some multiple of RNP level 

(e.g., twice the RNP level).

Standard RNP Levels

United States standard values supporting typical RNP 

airspace are shown in Figure 2-56. Other RNP levels as 

identified by ICAO, other states, and the FAA may also be 

used. 

Application of Standard RNP Levels

United States standard levels of RNP typically used for 

various routes and procedures supporting RNAV operations 

may be based on use of a specific navigational system 

or sensor, such as GPS, or on multi-sensor RNAV systems 

having suitable performance.

NOTE: The performance of navigation in RNP refers not only 

to the level of accuracy of a particular sensor or aircraft 

navigation system, but also to the degree of precision 

with which the aircraft is flown. Specific required flight 

procedures may vary for different RNP levels.

IFR En Route Altitudes

MEAs, minimum reception altitudes (MRA), maximum 

authorized altitudes (MAA), MOCA, minimum turning 

altitudes (MTA) and minimum crossing altitudes (MCA) are 

established by the FAA for instrument flight along Federal 

airways, as well as some off-airway routes. The altitudes are 

established after it has been determined that the NAVAIDs 

to be used are adequate and so oriented on the airways or 

routes that signal coverage is acceptable, and that flight 

can be maintained within prescribed route widths.

For IFR operations, regulations require that pilots operate 

their aircraft at or above minimum altitudes. Except when 

necessary for takeoff or landing, pilots may not operate an 

aircraft under IFR below applicable minimum altitudes, or 

if no applicable minimum altitude is prescribed, in the case 

of operations over an area designated as mountainous, an 

altitude of 2,000 feet above the highest obstacle within a 

horizontal distance of 4 NM from the course to be flown. In 

any other case, an altitude of 1,000 feet above the highest 

obstacle within a horizontal distance of 4 NM from the 

course to be flown must be maintained as a minimum 

altitude. If both a MEA and a MOCA are prescribed for a 

particular route or route segment, pilots may operate an 

aircraft below the MEA down to, but not below, the MOCA, 

only when within 22 NM of the VOR. When climbing to 

a higher minimum IFR altitude (MIA), pilots must begin 

climbing immediately after passing the point beyond 

which that minimum altitude applies, except when ground 

obstructions intervene, the point beyond which that higher 

minimum altitude applies must be crossed at or above the 

applicable MCA for the VOR.

If on an IFR flight plan, but cleared by ATC to maintain VFR 

conditions on top, pilots may not fly below minimum en 

route IFR altitudes. Minimum altitude rules are designed to 

ensure safe vertical separation between the aircraft and the 

terrain. These minimum altitude rules apply to all IFR flights, 

whether in IFR or VFR weather conditions, and whether 

assigned a specific altitude or VFR conditions on top.

Minimum En Route Altitude (MEA)

The MEA is the lowest published altitude between radio 

fixes that assures acceptable navigational signal coverage 

and meets obstacle clearance requirements between those 

fixes. The MEA prescribed for a Federal airway or segment, 

RNAV low or high route, or other direct route applies to the 

entire width of the airway, segment, or route between the 

radio fixes defining the airway, segment, or route. MEAs 

for routes wholly contained within controlled airspace 

normally provide a buffer above the floor of controlled 

airspace consisting of at least 300 feet within transition 

areas and 500 feet within control areas. MEAs are established 

based upon obstacle clearance over terrain and manmade 

objects, adequacy of navigation facility performance, and 

communications requirements.

RNAV Minimum En Route Altitude

RNAV MEAs are depicted on some IFR en route low altitude 

charts, allowing both RNAV and non-RNAV pilots to use the 

same chart for instrument navigation.

Minimum Reception Altitude (MRA)

MRAs are determined by FAA flight inspection traversing 

an entire route of flight to establish the minimum altitude 

the navigation signal can be received for the route and for 

off-course NAVAID facilities that determine a fix. When the 

MRA at the fix is higher than the MEA, an MRA is established 

for the fix and is the lowest altitude at which an intersection 

can be determined. 
2-36

Figure 2-58. Minimum obstacle clearance altitude (MOCA).

Minimum obstacle clearance altitude

Figure 2-57. Minimum authorized altitude (MAA).

Maximum Authorized Altitude (MAA)

An MAA is a published altitude representing the maximum 

usable altitude or flight level for an airspace structure 

or route segment. [Figure 2-57] It is the highest altitude 

on a Federal airway, jet route, RNAV low or high route, 

or other direct route for which an MEA is designated at 

which adequate reception of navigation signals is assured. 

MAAs represent procedural limits determined by technical 

limitations or other factors, such as limited airspace or 

frequency interference of ground-based facilities.

Minimum Obstruction Clearance Altitude 

(MOCA)

The MOCA is the lowest published altitude in effect between 

fixes on VOR airways, off-airway routes, or route segments 

that meets obstacle clearance requirements for the entire 

route segment. [Figure 2-58] This altitude also assures 

acceptable navigational signal coverage only within 22 NM 

of a VOR. The MOCA seen on the en route chart may have 

been computed by adding the required obstacle clearance 

(ROC) to the controlling obstacle in the primary area or 

computed by using a TERPS chart if the controlling obstacle 

is located in the secondary area. This figure is then rounded 
2-37

Figure 2-59. Minimum turning altitude (MTA).

MTA

V330 E to V520 W 16000 V465 NE to 330 W or V520 W 16000

Figure 2-60. Turning area at the intersection fix with NAVAID distance less than 51 NM.

Centerline

3.6°

4.5°

Fix displacement area

En route facility

Facility providing intersection radial

Primary area

Secondary area
2-38

Figure 2-61. Minimum turning altitude information located in the remarks section of FAA Form 8260-16 Transmittal of Airways/Route Data.

Airway

number

or route

V330 *9500E

# MTA

* 13400W JAC 10

300 MTN ROC RED 

DEL MCA ATIDA

COME ADD MCA 

AT OSITY DEC MOCA

INC MCA PRECIP

TER DEC MOCA

MEA CARDINAL ALT

JAC R-251 UNUSABLE 

BYD 10 # CHART:

MTA V330 E TO 

VS20W 16000

DEL directional MEA

MEA CARONIAL ALT

V330

Date Office Title Signature

From

To

Idaho Falls, ID VOR/DME

*Osity, ID

Osity, ID

# Jackson, WY VOR/DME

Routine

or docket

number

GNSS

MEA

Change

over point

Fix

MRA/MCA Remarks

Flight

inspection

dates

Controlling @

terrain/Obstruction

and coordinates

Tree 6177 @

432912.00N/1114118.00W

Terrain 6077

432912.00N/1114118.00W

AAO 12138 (SEC) @

434118.30N/1104858.30W

Terrain 11132

433900.00N/1105057.00W

MRA

MOCA

MAA

MEA

8000

--7900--

17500

8000

14000

--13600--

17500

14000

Transmittal of Airways/Route Data

AJW-3773 Manager Ray Nussear

to the nearest 100 foot increment (i.e., 2,049 feet becomes

2,000, and 2,050 feet becomes 2,100 feet). An extra 1,000

feet is added in mountainous areas, in most cases.

ATC controllers have an important role in helping pilots 

remain clear of obstructions. Controllers are instructed to 

issue a safety alert if the aircraft is in a position that, in their 

judgment, places the pilot in unsafe proximity to terrain, 

obstructions, or other aircraft. Once pilots inform ATC of 

action being taken to resolve the situation, the controller 

may discontinue the issuance of further alerts. A typical 

terrain/obstruction alert may sound like this: “(Aircraft call 

sign ), Low altitude alert. Check your altitude immediately. 

The MOCA in your area is 12,000.”

Minimum Turning Altitude (MTA)

Minimum turning altitude (MTA) is a charted altitude 

providing vertical and lateral obstruction clearance based 

on turn criteria over certain fixes, NAVAIDs, waypoints, 

and on charted route segments. [Figure 2-59] When a 

VHF airway or route terminates at a NAVAID or fix, the 

primary area extends beyond that termination point. 

When a change of course on VHF airways and routes is 

necessary, the en route obstacle clearance turning area 

extends the primary and secondary obstacle clearance 

areas to accommodate the turn radius of the aircraft. Since 

turns at or after fix passage may exceed airway and route 

boundaries, pilots are expected to adhere to airway and 

route protected airspace by leading turns early before a 

fix. The turn area provides obstacle clearance for both turn 

anticipation (turning prior to the fix) and flyover protection 

(turning after crossing the fix). This does not violate the 

requirement to fly the centerline of the airway. Many factors 

enter into the construction and application of the turning 

area to provide pilots with adequate obstacle clearance 

protection. These may include aircraft speed, the amount 

of turn versus NAVAID distance, flight track, curve radii, 

MEAs, and MTA. [Figure 2-60]

Due to increased airspeeds at 10,000 feet MSL or above, an 

expanded area in the vicinity of the turning fix is examined 

to ensure the published MEA is sufficient for obstacle 

clearance. In some locations (normally mountainous), 

terrain/obstacles in the expanded search area may obviate 

the published MEA and necessitate a higher minimum 

altitude while conducting the turning maneuver. Turning 

fixes requiring a higher MTA are charted with a flag along 

with accompanying text describing the MTA restriction. 

[Figure 2-59]

An MTA restriction normally consists of the ATS route 

leading to the turning fix, the ATS route leading from the 

turning fix, and an altitude (e.g., MTA V330 E TO V520

W 16000). When an MTA is applicable for the intended 

route of flight, pilots must ensure they are at or above the 

charted MTA prior to beginning the turn and maintain at 
2-39

Figure 2-62. Minimum crossing altitude (MCA).

V361

5200

V361

5900 SQWID

V 361 5900 E

X

Figure 2-63. Minimum crossing altitude (MCA) determination point.

700'

3200'

2000'

6 NM

4620' MSL

120' per NM required

Multiply by 6 NM −720 feet 

Maximum Displacement

MSL

X

MEA 5200'

MCA 5900' E

Obstruction height 4,620'

Required clearance +2000'

MOCA at obstruction =6,620'

Climb value* −720'

MCA required =5,900'

* Based upon 6 NM @ 120 feet per NM

Obstacle Line

2000'

or above the MTA until joining the centerline of the ATS 

route following the turn. Once established on the centerline 

following the turning fix, the MEA/MOCA determines the 

minimum altitude available for assignment.

An MTA may also preclude the use of a specific altitude or 

a range of altitudes during a turn. For example, the MTA 

may restrict the use of 10,000 through 11,000 feet MSL. 

In this case, any altitude greater than 11,000 feet MSL is 

unrestricted, as are altitudes less than 10,000 feet MSL 

provided MEA/MOCA requirements are satisfied.

All MTA information associated with the airway/route 

inbound to the turn fix/facility is put in the remarks section 

of FAA Form 8260-16, Transmittal of Airways/Route Data, 

using the following format [Figure 2-61]:

#CHART: MTA V330 E TO V520 W 16000

 (Document on V330 FAA Form 8260-16)

#CHART: MTA V465 NE TO V330 W OR V520 W 16000

 (Document on V465 FAA Form 8260-16)

When an MTA is required by TERPS, Volume 1, paragraph

1714(c), enter the MTA information in the REMARKS section 

of FAA Form 8260-2, Radio Fix and Holding Data Record, as 

specified on the appropriate FAA Form 8260-16, Transmittal 

of Airways/Route Data, using the following format:

MTA: V330 E TO V520 W 16000

MTA: V465 NE TO V330 W OR V520 W 16000
2-40

Figure 2-64. En route chart minimum crossing altitude data (outside of the U.S.).

NOT FOR NAVIGATION IN CANADA CROSS EACH FIX AT OR

ABOVE THE HIGHER MINIMUM EN ROUTE

IFR ALTITUDE APPLICABLE TO FLIGHT.

Minimum Crossing Altitude (MCA)

An MCA is the lowest altitude at certain fixes at which the 

aircraft must cross when proceeding in the direction of a 

higher minimum en route IFR altitude. [Figure 2-62] When 

applicable, MCAs are depicted on the en route chart. [Figure 

2-59] MCAs are established in all cases where obstacles 

intervene to prevent pilots from maintaining obstacle 

clearance during a normal climb to a higher MEA after 

passing a point beyond which the higher MEA applies. The 

same protected en route area vertical obstacle clearance 

requirements for the primary and secondary areas are 

considered in the determination of the MCA. The standard 

for determining the MCA is based upon the following climb 

gradients and is computed from the flight altitude:

•	 Sea level through 5,000 feet MSL—150 feet per NM

•	 5000 feet through 10,000 feet MSL—120 feet per

NM

•	 10,000 feet MSL and over—100 feet per NM

To determine the MCA seen on an en route chart, the 

distance from the obstacle to the fix is computed from 

the point where the centerline of the en route course in 

the direction of flight intersects the farthest displacement 

from the fix. [Figure 2-63] When a change of altitude is 

involved with a course change, course guidance must be 

provided if the change of altitude is more than 1,500 feet 

and/or if the course change is more than 45°, although 

there is an exception to this rule. In some cases, course 

changes of up to 90° may be approved without course 

guidance provided that no obstacles penetrate the 

established MEA requirement of the previous airway or 

route segment. Outside United States airspace, pilots may 

encounter different flight procedures regarding MCA and 

transitioning from one MEA to a higher MEA. In this case, 

pilots are expected to be at the higher MEA crossing the 

fix, similar to an MCA. Pilots must thoroughly review flight 

procedure differences when flying outside United States 

airspace. On IFR en route low altitude charts, routes and 

associated data outside the conterminous United States 

are shown for transitional purposes only and are not part 

of the high altitude jet route and RNAV route systems. 

[Figure 2-64]

Minimum IFR Altitude (MIA)

The MIA for operations is prescribed in 14 CFR Part 91. These 

MIAs are published on aeronautical charts and prescribed 

in 14 CFR Part 95 for airways and routes, and in

14 CFR Part 97 for standard instrument approach 
2-41

Figure 2-65. MVA chart.

SAMPLE NOT 

FOR ACTUAL USE 20

40

60

80

100

120

RKS 160 

RKS 080 

RKS 003 

RKS 269

RKS 325

211 

001 

065 

110 

180

270 

10,000 

RIW

15,800 

14,500 

12,000 

13,700 

10,700 

11,000 

12,000 12,400 

15,500 

14,200 

11,000 13,800 

13,300 

12,300 

14,500 

243 

065

142

CKW 

VEL 

FBR 

RKS 

070 

procedures. If no applicable minimum altitude is prescribed 

in 14 CFR Parts 95 or 97, the following MIA applies: In 

designated mountainous areas, 2,000 feet above the 

highest obstacle within a horizontal distance of 4 NM 

from the course to be flown; or other than mountainous 

areas, 1,000 feet above the highest obstacle within a 

horizontal distance of 4 NM from the course to be flown; or 

as otherwise authorized by the Administrator or assigned 

by ATC. MIAs are not flight checked for communication.

Minimum Vectoring Altitudes (MVA)

MVAs are established for use by ATC when radar ATC is 

exercised. The MVA provides 1,000 feet of clearance above 

the highest obstacle in non-mountainous areas and 2,000 

feet above the highest obstacle in designated mountainous 

areas. Because of the ability to isolate specific obstacles, 

some MVAs may be lower than MEAs, MOCAs, or other 

minimum altitudes depicted on charts for a given location. 

While being radar vectored, IFR altitude assignments by 

ATC are normally at or above the MVA.

Air traffic controllers use MVAs only when they are assured 

an adequate radar return is being received from the aircraft. 

Charts depicting MVAs are normally available to controllers 

but not available to pilots. SA is always important, especially 
2-42

Figure 2-66. IFR cruising altitude or flight level.

IFR

EVEN

2,000'

Intervals

begin at

18,000' MSL

VFR or

VFR-ON-TOP

EVEN

2,000'

Intervals

begin at

FL 185

IFR

ODD

2,000'

Intervals

begin at

FL 190

VFR or

VFR-ON-TOP

ODD

2,000'

Intervals

begin at

FL 195

359

M

180

0

179

M

18,000' MSL to flight level 290

IFR

EVEN

4,000'

Intervals

begin at

FL 310

VFR or

VFR-ON-TOP

4,000'

Intervals

begin at

FL 320

IFR

4,000'

Intervals

begin at

FL 290

VFR or

VFR-ON-TOP

4,000'

Intervals

begin at

FL 300

359

M

180

0

179

M

Flight level 290 and above

IFR

EVEN

thousands

VFR or

ON-TOP

EVEN

thousands

plus

500'

IFR

ODD

thousands

VFR or

ON-TOP

ODD

thousands

plus

500'

359

M

180

0

179

M

Cruising altitudes - U.S.

IFR within controlled airspace as assigned by ATC

For additional symbol information 

refer to the chart user’s guide.

VFR above 3000' AGL unless otherwise 

authorized by ATC IFR outside controlled 

airspace all courses are magnetic

NO VFR FLIGHTS WITHIN

CLASS A AIRSPACE

CRUISING ALTITUDES

IFR within controlled airspace as assigned by ATC

VFR above 3,000' AGL unless otherwise 

authorized by ATC IFR outside controlled 

airspace all courses are magnetic

when being radar vectored during a climb into an area with 

progressively higher MVA sectors, similar to the concept 

of MCA. Except where diverse vector areas have been 

established, when climbing, pilots should not be vectored 

into a sector with a higher MVA unless at or above the next 

sector’s MVA. Where lower MVAs are required in designated 

mountainous areas to achieve compatibility with terminal 

routes or to permit vectoring to an instrument approach 

procedure, 1,000 feet of obstacle clearance may be 

authorized with the use of Airport Surveillance Radar 

(ASR). The MVA provides at least 300 feet above the floor of 

controlled airspace. The MVA charts are developed to the 

maximum radar range. Sectors provide separation from 

terrain and obstructions. Each MVA chart has sectors large 

enough to accommodate vectoring of aircraft within the 

sector at the MVA. [Figure 2-65]

IFR Cruising Altitude or Flight Level

In controlled airspace, pilots must maintain the altitude or 

flight level assigned by ATC, although if the ATC clearance 

assigns “VFR conditions on-top,” an altitude or flight level 

as prescribed by 14 CFR Part 91, section 91.159 must be 

maintained. In uncontrolled airspace (except while in a 

holding pattern of two minutes or less or while turning) if 

operating an aircraft under IFR in level cruising flight, an 

appropriate altitude as depicted in the legend of IFR en 

route high and low altitude charts must be maintained. 

[Figure 2-66]

When operating on an IFR flight plan below 18,000 feet 

MSL in accordance with a VFR-on-top clearance, any VFR 

cruising altitude appropriate to the direction of flight 

between the MEA and 18,000 feet MSL may be selected that 

allows the flight to remain in VFR conditions. Any change in 

altitude must be reported to ATC, and pilots must comply 

with all other IFR reporting procedures. VFR-on-top is not 

authorized in Class A airspace. When cruising below 18,000 

feet MSL, the altimeter must be adjusted to the current 

setting, as reported by a station within 100 NM of your 

position. In areas where weather-reporting stations are 

more than 100 NM from the route, the altimeter setting of 

a station that is closest may be used.

During IFR flight, ATC advises flights periodically of the 

current altimeter setting, but it remains the responsibility 

of the pilot or flight crew to update altimeter settings in a 
2-43

timely manner. Altimeter settings and weather information 

are available from weather reporting facilities operated or 

approved by the U.S. National Weather Service, or a source 

approved by the FAA. Some commercial operators have 

the authority to act as a government-approved source of 

weather information, including altimeter settings, through 

certification under the FAA’s Enhanced Weather Information 

System.

Flight level operations at or above 18,000 feet MSL require 

the altimeter to be set to 29.92 inches of mercury (" Hg). A 

flight level (FL) is defined as a level of constant atmospheric 

pressure related to a reference datum of 29.92 " Hg. Each 

flight level is stated in three digits that represent hundreds of 

feet. For example, FL 250 represents an altimeter indication 

of 25,000 feet. Conflicts with traffic operating below 18,000 

feet MSL may arise when actual altimeter settings along the 

route of flight are lower than 29.92 " Hg. Therefore, 14 CFR 

Part 91, section 91.121 specifies the lowest usable flight 

levels for a given altimeter setting range.

Reduced Vertical Separation Minimums (RSVM)

Reduced vertical separation minimums (RVSM) is a term 

used to describe the reduction of the standard vertical 

separation required between aircraft flying at levels 

between FL 290 (29,000 feet) and FL 410 (41,000 feet) 

from 2,000 feet to 1,000 feet. The purpose, therefore, 

increases the number of aircraft that can safely fly in a 

particular volume of airspace. Historically, standard vertical 

separation was 1,000 feet from the surface to FL 290, 2,000 

feet from FL 290 to FL 410 and 4,000 feet above this. This 

was because the accuracy of the pressure altimeter (used 

to determine altitude) decreases with height. Over time, 

air data computers (ADCs) combined with altimeters 

have become more accurate and autopilots more adept 

at maintaining a set level; therefore, it became apparent 

that for many modern aircraft, the 2,000 foot separation 

was not required . It was therefore proposed by ICAO that 

this be reduced to 1,000 feet.

Between 1997 and 2005, RVSM was implemented in all of 

Europe, North Africa, Southeast Asia, North America, South 

America, and over the North Atlantic, South Atlantic, and 

Pacific Oceans. The North Atlantic implemented initially in 

March 1997, at FL 330 through FL 370. The entire western 

hemisphere implemented RVSM FL 290–FL 410 on January 

20, 2005.

Only aircraft with specially certified altimeters and 

autopilots may fly in RVSM airspace, otherwise the aircraft 

must fly lower or higher than the airspace, or seek special 

exemption from the requirements. Additionally, aircraft 

operators (airlines or corporate operators) must receive 

specific approval from the aircraft’s state of registry in 

order to conduct operations in RVSM airspace. Non-RVSM 

approved aircraft may transit through RVSM airspace 

provided they are given continuous climb throughout the 

designated airspace, and 2,000 feet vertical separation is 

provided at all times between the non-RVSM flight and all 

others for the duration of the climb/descent.

Critics of the change were concerned that by reducing 

the space between aircraft, RVSM may increase the 

number of mid-air collisions and conflicts. In the ten 

years since RVSM was first implemented, not one 

collision has been attributed to RVSM. In the United 

States, this program was known as the Domestic 

Reduced Vertical Separation Minimum (DRVSM).

Cruise Clearance

The term “cruise” may be used instead of “maintain” to 

assign a block of airspace to an aircraft. The block extends 

from the minimum IFR altitude up to and including the 

altitude that is specified in the cruise clearance. On a cruise 

clearance, you may level off at any intermediate altitude 

within this block of airspace. You are allowed to climb or 

descend within the block at your own discretion. However, 

once you start descent and verbally report leaving an 

altitude in the block to ATC, you may not return to that 

altitude without an additional ATC clearance. A cruise 

clearance also authorizes you to execute an approach at 

the destination airport.

Lowest Usable Flight Level

When the barometric pressure is 31.00 " Hg or less and 

pilots are flying below 18,000 feet MSL, use the current 

reported altimeter setting. When an aircraft is en route 

on an instrument flight plan, air traffic controllers furnish 

this information at least once while the aircraft is in the 

controller’s area of jurisdiction. When the barometric 

pressure exceeds 31.00 " Hg, the following procedures are 

placed in effect by NOTAM defining the geographic area 

affected: Set 31.00 " Hg for en route operations below 

18,000 feet MSL and maintain this setting until beyond 

the affected area. ATC issues actual altimeter settings and 

advises pilots to set 31.00 " Hg in their altimeter, for en route 

operations below 18,000 feet MSL in affected areas. If an 

aircraft has the capability of setting the current altimeter 

setting and operating into airports with the capability of 

measuring the current altimeter setting, no additional 

restrictions apply. At or above 18,000 feet MSL, altimeters 

should be set to 29.92 " Hg (standard setting). Additional 

procedures exist beyond the en route phase of flight.

The lowest usable flight level is determined by the 

atmospheric pressure in the area of operation. As local 
2-44

Figure 2-67. Altimeter setting changes.

FAA AIR SERVICE OUTSIDE U.S. AIRSPACE 

IS PROVIDED IN ACCORDANCE WITH 

ARTICLE 12 AND ANNEX 11 OF ICAO 

CONVENTION. ICAO CONVENTION NOT 

APPLICABLE TO STATE AIRCRAFT BUT 

COMPLIANCE WITH ICAO STANDARDS 

NOT FOR NAVIGATION

AND PRACTICES IS ENCOURAGED.

MONCTON FIR

CZQM

ALTIMETER

 

QNH

QNE

CRABB

N42° 13.00 ́

W65° 44.00 ́

altimeter settings fall below 29.92 " Hg, pilots operating 

in Class A airspace must cruise at progressively higher 

indicated altitudes to ensure separation from aircraft 

operating in the low altitude structure as follows:

Current Altimeter Setting Lowest Usable Flight Level

29.92 or higher 180

29.91 to 29.42 185

29.41 to 28.92 190

28.91 to 28.42 195

28.41 to 27.91 200

When the minimum altitude, as prescribed in 14 CFR Part 

91, sections 91.159 and 91.177, is above 18,000 feet MSL, 

the lowest usable flight level is the flight level equivalent 

of the minimum altitude plus the number of feet specified 

according to the lowest flight level correction factor as 

follows:

Altimeter Setting Correction Factor

29.92 or higher —

29.91 to 29.42 500 feet

29.41 to 28.92 1,000 feet

28.91 to 28.42 1,500 feet

28.41 to 27.91 2,000 feet

27.91 to 27.42 2,500 feet

Operations in Other Countries

When flight crews transition from the U.S. NAS to another 

country’s airspace, they should be aware of differences not 

only in procedures but also airspace. For example, when 

flying into Canada as depicted in Figure 2-67, notice the 

change from transition level (QNE) to transition altitude 

(QNH) when flying north-bound into the Moncton flight 

information region (FIR).
2-45

Figure 2-68. ATC reporting procedures.

RADAR/NON-RADAR REPORTS

These reports should be made at all times without a specific ATC request.

Leaving one assigned flight altitude or flight level for another

VFR-on-top change in altitude

Leaving any assigned holding fix or point

Missed approach

Unable to climb or descend at least 500 feet per minute

TAS variation from filed speed of 5% or 10 knots, whichever

is greater

Time and altitude or flight level upon reaching a holding fix

or clearance limit

Loss of Nav/Comm capability (required by Part 91.187)

Unforecast weather conditions or other information relating

to the safety of flight (required by Part 91.183) 

"Marathon 564, leaving 8,000, climb to 10,000."

"Marathon 564, VFR-on-top, climbing to 10,500."

"Marathon 564, leaving FARGO Intersection."

"Marathon 564, missed approach, request clearance to Chicago."

"Marathon 564, maximum climb rate 400 feet per minute."

"Marathon 564, advises TAS decrease to140 knots."

"Marathon 564, FARGO Intersection at 05, 10,000, holding east."

"Marathon 564, ILS receiver inoperative."

"Marathon 564, experiencing moderate turbulence at 10,000."

NON-RADAR REPORTS

When you are not in radar contact, these reports should be made without a specific request from ATC.

Leaving FAF or OM inbound on final approach

Revised ETA of more than three minutes

"Marathon 564, outer marker inbound, leaving 2,000."

"Marathon 564, revising SCURRY estimate to 55."

REPORTS EXAMPLE

REPORTS EXAMPLE

Operations in international airspace demand that pilots 

are aware of, and understand the use of, the three types 

of altimeter settings. Most overseas airports give altimeter 

settings in hectopascals (hPa) (millibars). Therefore, it is 

imperative that pilots or on-board equipment are able 

to accurately convert inches of mercury to hPa, or hPa to 

inches of mercury.

Altitude Above Ground (QFE)

A local altimeter setting equivalent to the barometric 

pressure measured at an airport altimeter datum, usually 

signifying the approach end of the runway is in use. At the 

airport altimeter datum, an altimeter set to QFE indicates 

zero altitude. If required to use QFE altimetry, altimeters 

are set to QFE while operating at or below the transition 

altitude and below the transition level. On the airport, the 

altimeter will read “0” feet.

Barometric Pressure for Standard Altimeter 

Setting (QNE)

Use the altimeter setting (en route) at or above the 

transition altitude (FL 180 in the United States). The 

altimeter setting is always 29.92 inches of mercury/1013.2 

hPa for a QNE altitude. Transition levels differ from country 

to country and pilots should be particularly alert when 

making a climb or descent in a foreign area.

Barometric Pressure for Local Altimeter Setting 

(QNH)

A local altimeter setting equivalent to the barometric 

pressure measured at an airport altimeter datum and 

corrected to sea level pressure. At the airport altimeter 

datum, an altimeter set to QNH indicates airport elevation 

above mean sea level (MSL). Altimeters are set to QNH 

while operating at and below the transition altitude and 

below the transition level.

For flights in the vicinity of airports, express the vertical 

position of aircraft in terms of QNH or QFE at or below the 

transition altitude and in terms of QNE at or above the 

transition level. While passing through the transition layer, 

express vertical position in terms of FLs when ascending 

and in terms of altitudes when descending.

When an aircraft that receives a clearance as number one 

to land completes its approach using QFE, express the 

vertical position of the aircraft in terms of height above 

the airport elevation during that portion of its flight for 

which you may use QFE.

It is important to remember that most pressure altimeters 

are subject to mechanical, elastic, temperature, and 

installation errors. In addition, extremely cold temperature 

differences may also require altimeter correction factors 

as appropriate.
2-46

Figure 2-69. Two-way radio communications failure transponder code.

When an aircraft squawks code 7600 during a two-way radio 

communication failure, the information block on the radar 

screen flashes RDOF (radio failure) to alert the controller.

En Route Reporting Procedures 

In addition to acknowledging a handoff to another Center 

en route controller, there are reports that should be made 

without a specific request from ATC. Certain reports should 

be made at all times regardless of whether a flight is in radar 

contact with ATC, while others are necessary only if radar 

contact has been lost or terminated. [Figure 2-68]

Non-Radar Position Reports

If radar contact has been lost or radar service terminated, 

the CFRs require pilots to provide ATC with position reports 

over designated VORs and intersections along their route 

of flight. These compulsory reporting points are depicted 

on IFR en route charts by solid triangles. Position reports 

over fixes indicated by open triangles are noncompulsory 

reporting points and are only necessary when requested by 

ATC. If on a direct course that is not on an established airway, 

report over the fixes used in the flight plan that define 

the route, since they automatically become compulsory 

reporting points. Compulsory reporting points also apply 

when conducting an IFR flight in accordance with a VFRon-top clearance.

Whether a route is on an airway or direct, position reports 

are mandatory in a non-radar environment, and they 

must include specific information. A typical position 

report includes information pertaining to aircraft position, 

expected route, and ETA. When a position report is to be 

made passing a VOR radio facility, the time reported should 

be the time at which the first complete reversal of the TO/

FROM indicator is accomplished. When a position report is 

made passing a facility by means of an airborne ADF, the 

time reported should be the time at which the indicator 

makes a complete reversal. When an aural or a light panel 

indication is used to determine the time passing a reporting 

point, such as a fan marker, Z marker, cone of silence or 

intersection of range courses, the time should be noted 

when the signal is first received and again when it ceases. 

The mean of these two times should then be taken as the 

actual time over the fix. If a position is given with respect to 

distance and direction from a reporting point, the distance 

and direction should be computed as accurately as possible. 

Except for terminal area transition purposes, position 

reports or navigation with reference to aids not established 

for use in the structure in which flight is being conducted 

are not normally required by ATC.

Flights in a Radar Environment

When informed by ATC that their aircraft are in “Radar 

Contact,” pilots should discontinue position reports over 

designated reporting points. They should resume normal 

position reporting when ATC advises “radar contact lost” 

or “radar service terminated.” ATC informs pilots that they 

are in radar contact:

1. When their aircraft is initially identified in the ATC 

system; and

2. When radar identification is reestablished after radar 

service has been terminated or radar contact lost.

Subsequent to being advised that the controller has 

established radar contact, this fact is not repeated to the 

pilot when handed off to another controller. At times, the 

aircraft identity is confirmed by the receiving controller; 

however, this should not be construed to mean that 

radar contact has been lost. The identity of transponder 

equipped aircraft is confirmed by asking the pilot to “ident,” 

“squawk standby,” or to change codes. Aircraft without 

transponders are advised of their position to confirm 

identity. In this case, the pilot is expected to advise the 

controller if in disagreement with the position given. Any 

pilot who cannot confirm the accuracy of the position given 

because of not being tuned to the NAVAID referenced by 

the controller should ask for another radar position relative 

to the tuned in NAVAID.

Position Report Items

Position reports should include the following items: 

1. Aircraft identification

2. Position 

3. Time 

4. Altitude or flight level (include actual altitude or flight 

level when operating on a clearance specifying VFRon-top)

5. Type of flight plan (not required in IFR position reports 

made directly to ARTCCs or approach control)

6. ETA and name of next reporting point 
2-47

7. The name only of the next succeeding reporting point 

along the route of flight 

8. Pertinent remarks 

Additional Reports

The following reports should be made at all times to ATC or 

FSS facilities without a specific ATC request: 

1. When vacating any previously assigned altitude or 

flight level for a newly assigned altitude or flight level. 

2. When an altitude change is made if operating on a 

clearance specifying VFR-on-top. 

3. When unable to climb/descend at a rate of a least 500 

feet per minute (fpm). 

4. When approach has been missed. (Request clearance 

for specific action (i.e., to alternative airport, another 

approach). 

5. Change in the average true airspeed (at cruising 

altitude) when it varies by 5 percent or 10 knots 

(whichever is greater) from that filed in the flight plan. 

6. The time and altitude or flight level upon reaching a 

holding fix or point to which cleared. 

7. When leaving any assigned holding fix or point. 

NOTE: The reports stated in subparagraphs 6 and 

7 may be omitted by pilots of aircraft involved in 

instrument training at military terminal area facilities 

when radar service is being provided.

8. Any loss, in controlled airspace, of VOR, TACAN, 

ADF, low frequency navigation receiver capability, 

GPS anomalies while using installed IFR-certified 

GPS/GNSS receivers, complete or partial loss of ILS 

receiver capability or impairment of air/ground 

communications capability. Reports should include 

aircraft identification, equipment affected, degree 

to which the capability to operate under IFR in the 

ATC system is impaired, and the nature and extent 

of assistance desired from ATC. 

9. Any information relating to the safety of flight. 

Other equipment installed in an aircraft may effectively 

impair safety and/or the ability to operate under IFR. If such 

equipment (e.g., airborne weather radar) malfunctions and 

in the pilot’s judgment either safety or IFR capabilities are 

affected, reports should be made as stated above. When 

reporting GPS anomalies, include the location and altitude

of the anomaly. Be specific when describing the location 

and include duration of the anomaly if necessary.

Communication Failure

Two-way radio communication failure procedures for IFR 

operations are outlined in 14 CFR Part 91, section 91.185. 

Unless otherwise authorized by ATC, pilots operating under 

IFR are expected to comply with this regulation. Expanded 

procedures for communication failures are found in the 

Aeronautical Information Manual (AIM). Pilots can use the 

transponder to alert ATC to a radio communication failure by 

squawking code 7600. [Figure 2-69] If only the transmitter 

is inoperative, listen for ATC instructions on any operational 

receiver, including the navigation receivers. It is possible ATC 

may try to make contact with pilots over a VOR, VORTAC, 

NDB, or localizer frequency. In addition to monitoring 

NAVAID receivers, attempt to reestablish communications 

by contacting ATC on a previously assigned frequency or 

calling an FSS.

The primary objective of the regulations governing 

communication failures is to preclude extended IFR 

no-radio operations within the ATC system since these 

operations may adversely affect other users of the airspace. 

If the radio fails while operating on an IFR clearance, but 

in VFR conditions, or if encountering VFR conditions at 

any time after the failure, continue the flight under VFR 

conditions, if possible, and land as soon as practicable. The 

requirement to land as soon as practicable should not be 

construed to mean as soon as possible. Pilots retain the 

prerogative of exercising their best judgment and are not 

required to land at an unauthorized airport, at an airport 

unsuitable for the type of aircraft flown, or to land only 

minutes short of their intended destination. However, if 

IFR conditions prevail, pilots must comply with procedures 

designated in the CFRs to ensure aircraft separation.

If pilots must continue their flight under IFR after 

experiencing two-way radio communication failure, they 

should fly one of the following routes:

•	 The route assigned by ATC in the last clearance

received.

•	 Ifbeingradarvectored,thedirectroutefromthepoint

of radio failure to the fix, route, or airway specified in 

the radar vector clearance.

•	 In the absence of an assigned route, the route ATC

has advised to expect in a further clearance.

•	 In the absence of an assigned or expected route,the

route filed in the flight plan.

It is also important to fly a specific altitude should two-way 

radio communications be lost. The altitude to fly after a 

communication failure can be found in 14 CFR Part 91, 

section 91.185 and must be the highest of the following 

altitudes for each route segment flown.
2-48

•	 The altitude or flight level assigned in the last ATC

clearance.

•	 The minimum altitude or flight level for IFR

operations.

•	 The altitude or flightlevelATC has advised to expect

in a further clearance.

In some cases, the assigned or expected altitude may not be as 

high as the MEA on the next route segment. In this situation, 

pilots normally begin a climb to the higher MEA when they 

reach the fix where the MEA rises. If the fix also has a published 

MCA, they start the climb so they are at or above the MCA 

when reaching the fix. If the next succeeding route segment 

has a lower MEA, descend to the applicable altitude either 

the last assigned altitude or the altitude expected in a further 

clearance—when reaching the fix where the MEA decreases.

ARTCC Radio Frequency Outage

ARTCCs normally have at least one back-up radio receiver 

and transmitter system for each frequency that can usually 

be placed into service quickly with little or no disruption of 

ATC service. Occasionally, technical problems may cause a 

delay but switchover seldom takes more than 60 seconds. 

When it appears that the outage is not quickly remedied, 

the ARTCC usually requests a nearby aircraft, if there is 

one, to switch to the affected frequency to broadcast 

communications instructions. It is important that the pilot 

wait at least 1 minute before deciding that the ARTCC has 

actually experienced a radio frequency failure. When such 

an outage does occur, the pilot should, if workload and 

equipment capability permit, maintain a listening watch 

on the affected frequency while attempting to comply with 

the following recommended communications procedures: 

1. If two-way communications cannot be established 

with the ARTCC after changing frequencies, a pilot 

should attempt to re-contact the transferring 

controller for the assignment of an alternative 

frequency or other instructions. 

2. When an ARTCC radio frequency failure occurs after 

two-way communications have been established, 

the pilot should attempt to reestablish contact with 

the center on any other known ARTCC frequency, 

preferably that of the next responsible sector when 

practicable, and ask for instructions. However, 

when the next normal frequency change along 

the route is known to involve another ATC facility, 

the pilot should contact that facility, if feasible, 

for instructions. If communications cannot be 

reestablished by either method, the pilot is expected 

to request communication instructions from the FSS 

appropriate to the route of flight. 

NOTE: The exchange of information between an aircraft 

and an ARTCC through an FSS is quicker than relay via 

company radio because the FSS has direct interphone 

lines to the responsible ARTCC sector. Accordingly, 

when circumstances dictate a choice between the two 

during an ARTCC frequency outage relay via FSS radio is 

recommended.

Climbing and Descending En Route

When ATC issues a clearance or instruction, pilots are 

expected to execute its provisions upon receipt. In some 

cases, ATC includes words that modify their expectation. 

For example, the word “immediately” in a clearance or 

instruction is used to impress urgency to avoid an imminent 

situation, and expeditious compliance is expected and 

necessary for safety. The addition of a climb point or time 

restriction, for example, does not authorize pilots to deviate 

from the route of flight or any other provision of the ATC 

clearance. If the pilot receives the term “climb at pilot’s 

discretion” in the altitude information of an ATC clearance, 

it means that the pilot has the option to start a climb when 

they desire and are authorized to climb at any rate, and to 

temporarily level off at any intermediate altitude as desired, 

although once you vacate an altitude, you may not return to 

that altitude. When ATC has not used the term nor imposed 

any climb restrictions, pilots should climb promptly on 

acknowledgment of the clearance. Climb at an optimum 

rate consistent with the operating characteristics of the 

aircraft to 1,000 feet below the assigned altitude, and then 

attempt to climb at a rate of between 500 and 1,500 fpm 

until the assigned altitude is reached. If at any time the 

pilot is unable to climb at a rate of at least 500 fpm, advise 

ATC. If it is necessary to level off at an intermediate altitude 

during climb, advise ATC.

When ATC issues the instruction, “Expedite climb,” this 

normally indicates that the pilot should use the approximate 

best rate of climb without an exceptional change in aircraft 

handling characteristics. Normally controllers inform pilots of 

the reason for an instruction to expedite. If flying a turbojet 

airplane equipped with afterburner engines, such as a 

military aircraft, pilots should advise ATC prior to takeoff if 

intending to use afterburning during the climb to the en 

route altitude. Often, the controller may be able to plan 

traffic to accommodate a high performance climb and allow 

the pilot to climb to the planned altitude without “expedite” 

clearance from restriction. If you receive an ATC instruction, 

and your altitude to maintain is subsequently changed 

or restated without an expedite instruction, the expedite 

instruction is canceled.

During en route climb, as in any other phase of flight, 

it is essential that you clearly communicate with ATC 

regarding clearances. In the following example, a flight crew 
2-49

Figure 2-70. Holding pattern design criteria template.

Secondary area

Primary area holding pattern airspace area Fix displacement area

Facility

Facility

experienced an apparent clearance readback/hearback 

error, that resulted in confusion about the clearance and, 

ultimately, to inadequate separation from another aircraft. 

“Departing IFR, clearance was to maintain 5,000 feet, 

expect 12,000 in 10 minutes.” After handoff to Center, the 

pilot understood and read back, “Leaving 5,000 turn left 

heading 240° for vector on course.” The pilot turned to the 

assigned heading climbing through 5,000 feet. At 5,300 feet, 

Center advised assigned altitude was 5,000 feet. The pilot 

immediately descended to 5,000. Center then informed 

the pilot that there was traffic at 12 o’clock and a mile at 

6,000. After passing traffic, a higher altitude was assigned 

and climb resumed. The pilot then believed the clearance 

was probably "reaching" 5,000, etc. Even the readback to the 

controller with "leaving" did not catch the different wording. 

“Reaching” and “leaving” are commonly used ATC terms 

having different usages. They may be used in clearances 

involving climbs, descents, turns, or speed changes. In the 

flight deck, the words “reaching” and “leaving” sound much 

alike.

For altitude awareness during climb, pilots often call out

altitudes on the flight deck. The pilot monitoring may call

2,000 and 1,000 feet prior to reaching an assigned altitude. 

The callout may be, “two” climbing through the transit 

to go altitude (QNH), both pilots set their altimeters to 

29.92 inches of mercury and announce “2992 inches” (or 

‘standard,’ on some airplanes) and the flight level passing. 

For example, “2992 inches” (standard), flight level one 

eight zero. The second officer on three pilot crews may 

ensure that both pilots have inserted the proper altimeter 

setting. On international flights, pilots must be prepared 

to differentiate, if necessary, between barometric pressure 

equivalents with inches of mercury, and millibars or 

hectopascals, to eliminate any potential for error. For 

example, 996 millibars erroneously being set as 2996.

For a typical IFR flight, the majority of in-flight time often 

is flown in level flight at cruising altitude from top of climb 

(TOC) to top of descent (TOD). Generally, TOD is used in 

airplanes with a FMS and represents the point at which 

descent is first initiated from cruise altitude. FMS also 

assist in level flight by cruising at the most fuel saving 

speed, providing continuing guidance along the flight plan 

route including great circle direct routes, and continuous 

evaluation and prediction of fuel consumption along with 

changing clearance data. 

Aircraft Speed and Altitude

During the en route descent phase of flight, an additional 

benefit a FMS is that it provides fuel saving idle thrust 

descent to your destination airport. This allows an 
2-50

Figure 2-71. ATC holding instructions.

NOT FOR NAVIGATION

"...Hold southeast

of PINNE Intersection as published.

Expect further clearance at 1645."

There are at least three items in a clearance for a charted holding pattern:

• Direction to hold from the holding fix

• Holding fix

• Expect further clearance time

A clearance for an uncharted holding pattern contains additional information: 

• Direction to hold from holding fix

• Holding fix

• The holding course (a specified radial, 

 magnetic bearing, airway or route number)

• The outbound leg length in minutes or 

 nautical miles when DME is used

• Nonstandard pattern, if used

• Expect further clearance time

"...Hold west

of Horst Intersection

on Victor 8

5 mile legs

left turns

expect further clearance at 1430."

Figure 2-72. Clearance limit holding.

CHERRELYN D

( H )117.2 CHL

331°

269°

221°

126°

V214

uninterrupted profile descent from level cruising altitude 

to an appropriate MIA, except where level flight is required 

for speed adjustment.. Controllers anticipate and plan that 

the pilot may level off at 10,000 feet MSL on descent to 

comply with the 14 CFR Part 91 indicated airspeed limit of 

250 knots. Leveling off at any other time on descent may 

seriously affect air traffic handling by ATC. It is imperative 

that pilots make every effort to fulfill ATC expected actions 

on descent to aid in safely handling and expediting air 

traffic.

ATC issues speed adjustments if the flight is being radar 

controlled to achieve or maintain required or desired 

spacing. They express speed adjustments in terms of knots 

based on indicated airspeed in 10 knot increments except 

that at or above FL 240 speeds may be expressed in terms 

of Mach numbers in 0.01 increments. The use of Mach 

numbers by ATC is restricted to turbojets. If complying 

with speed adjustments, pilots are expected to maintain 

that speed within plus or minus 10 knots or 0.02 Mach.

Speed and altitude restrictions in clearances are subject 

to misinterpretation, as evidenced in this case where a 

corporate flight crew treated instructions in a published 

procedure as a clearance. The aircraft was at FL 310 and 

had already programmed the ‘expect-crossing altitude’ of 

17,000 feet at the VOR. When the altitude alerter sounded, 

the pilot advised Center that we were leaving FL 310. ATC 

acknowledged with a “Roger.” At FL 270, Center questioned 

the pilot about the aircrafts descent. The pilot told the 

controller that the reason for the descent was to cross the 

VOR at 17,000 feet. ATC advised the pilot that he did not 
2-51

Figure 2-73. Maximum holding speeds for different altitudes.

Maximum Holding Airspeed: KIAS 2 6 5

Maximum Holding Airspeed: KIAS 2 3 0

Maximum Holding Airspeed: KIAS 2 0 0

14,001'

MSL

14,000'

MSL

6,000'

MSL

Minimum

Holding

Altitude

(MHA)

6,001'

MSL

have clearance to descend. What the pilot thought was a 

clearance was in fact an “expect” clearance. Whenever pilots 

are in doubt about a clearance it is imperative they request 

clarity from ATC. Also, the term “Roger” only means that ATC 

received the transmission, not that they understood the 

transmission. “Expect” altitudes are published for planning 

purposes and are not considered crossing restrictions until 

verbally issued by ATC.

En Route Holding Procedures

The criteria for holding pattern airspace is developed 

both to provide separation of aircraft, as well as obstacle 

clearance. The alignment of holding patterns typically 

coincides with the flight course you fly after leaving the 

holding fix. For level holding, a minimum of 1,000 feet 

obstacle clearance is provided throughout the primary 

area. In the secondary area, 500 feet of obstacle clearance 

is provided at the inner edge, tapering to zero feet at the 

outer edge. Allowance for precipitous terrain is considered, 

and the altitudes selected for obstacle clearance may be 

rounded to the nearest 100 feet. When criteria for a climb 

in hold are applied, no obstacle penetrates the holding 

surface. [Figure 2-70]

There are many factors that affect aircraft during holding 

maneuvers, including navigational aid ground and airborne 

tolerance, effect of wind, flight procedures, application of 

ATC, outbound leg length, maximum holding airspeeds, 

fix to NAVAID distance, DME slant range effect, holding 

airspace size, and altitude holding levels.

ATC Holding Instructions

When controllers anticipate a delay at a clearance limit or 

fix, pilots are usually issued a holding clearance at least

5 minutes before the ETA at the clearance limit or fix. If 

the holding pattern assigned by ATC is depicted on the 

appropriate aeronautical chart, pilots are expected to hold 

as charted. In the following example, the controller issues a 

holding clearance that includes the name of the fix, directs 

the pilot to hold as charted, and includes an expect further 

clearance (EFC) time.

“Marathon five sixty four, hold east of MIKEY Intersection 

as published, expect further clearance at 1521.”

When ATC issues a clearance requiring you to hold at a fix 

where a holding pattern is not charted, pilots are issued 

complete holding instructions. The holding instructions 

include the direction from the fix, name of the fix, course, 

leg length, if appropriate, direction of turns (if left turns 

are required), and the EFC time. Pilots are required to 

maintain the last assigned altitude unless a new altitude is 

specifically included in the holding clearance and should 

fly right turns unless left turns are assigned. Note that all 

holding instructions should include an EFC time. In the 

event that two-way radio communication is lost, the EFC 

allows the pilot to depart the holding fix at a definite time. 

Pilots should plan the last lap of the holding pattern to 

leave the fix as close as possible to the exact time. [Figure 

2-71]

When approaching the clearance limit and you have 

not received holding instructions from ATC, pilots are 

expected to follow certain procedures. First, call ATC 

and request further clearance before reaching the fix. If 

further clearance cannot be obtained, pilots are expected 

to hold at the fix in compliance with the charted holding 

pattern. If a holding pattern is not charted at the fix, pilots 

are expected to hold on the inbound course using right 

turns. This procedure ensures that ATC provides adequate 

separation. [Figure 2-72] For example, the aircraft is heading 

eastbound on V214 and the Cherrelyn VORTAC is the 

clearance limit and the pilot has not been able to obtain 

further clearance and has not received holding instructions, 

plan to hold southwest on the 221° radial using left-hand 

turns, as depicted. If this holding pattern is not charted, 

hold west of the VOR on V214 using right-hand turns.

Where required for aircraft separation, ATC may request 

that the pilot hold at any designated reporting point in a 

standard holding pattern at the MEA or the MRA, whichever 

altitude is the higher at locations where a minimum holding 

altitude has not been established. Unplanned holding at 

en route fixes may be expected on airway or route radials, 
2-52

bearings, or courses. If the fix is a facility, unplanned 

holding could be on any radial or bearing and there may 

be holding limitations required if standard holding cannot 

be accomplished at the MEA or MRA.

Maximum Holding Speed

The size of the holding pattern is directly proportional 

to the speed of the airplane. In order to limit the amount 

of airspace that must be protected by ATC, maximum 

holding speeds in knots indicated airspeed (KIAS) have 

been designated for specific altitude ranges. [Figure 2-73] 

Even so, some holding patterns may have additional speed 

restrictions to keep faster airplanes from flying out of the 

protected area. If a holding pattern has a nonstandard 

speed restriction, it is depicted by an icon with the limiting 

airspeed. If the holding speed limit is less than the pilot feels 

necessary, advise ATC of the revised holding speed. Also, if 

the indicated airspeed exceeds the applicable maximum 

holding speed, ATC expects the pilot to slow to the speed 

limit within three minutes of the ETA at the holding fix. 

Often pilots can avoid flying a holding pattern, or reduce 

the length of time spent in the holding pattern, by slowing 

down on the way to the holding fix. 

High Performance Holding

When operating at higher airspeeds, there are certain 

limitations that must be adhered to. For example, aircraft do 

not make standard rate turns in holding patterns if the bank 

angle exceeds 30°. If your aircraft is using a flight director 

system, the bank angle is limited to 25°. The aircraft must 

be traveling over 210 knots true airspeed (TAS) for the bank 

angle in a standard rate turn to exceed 30°, therefore this 

limit applies to relatively fast airplanes. An aircraft using 

a flight director would have to be holding at more than 

170 knots TAS to come up against the 25° limit. These true 

airspeeds correspond to indicated airspeeds of about 183 

and 156 knots, respectively, at 6,000 feet in a standard 

atmosphere.

En Route Safety Considerations

Fuel State Awareness

In order to increase fuel state awareness, pilots are required 

to record the time and fuel remaining during an IFR flight. 

For example, on a flight scheduled for one hour or less, the 

flight crew may record the time and fuel remaining at the 

top of climb (TOC) and at one additional waypoint listed in 

the flight plan. Generally, TOC is used in airplanes with an 

FMS, and represents the point at which cruise altitude is 

first reached. TOC is calculated based on current airplane 

altitude, climb speed, and cruise altitude. The pilot may elect 

to delete the additional waypoint recording requirement 

if the flight is so short that the record will not assist in the 

management of the flight. For flights scheduled for more 

than one hour, the pilot may record the time and fuel 

remaining shortly after TOC and at selected waypoints 

listed in the flight plan, conveniently spaced approximately 

one hour apart. The actual fuel burn is then compared to 

the planned fuel burn. Each fuel tank must be monitored 

to verify proper burn off and appropriate fuel remaining. 

For two-pilot airplanes, the pilot monitoring (PM) keeps 

the flight plan record. On three-pilot airplanes, the second 

officer and PM coordinate recording and keeping the flight 

plan record. In all cases, the crew member(s) making the 

recording communicates the information to the pilot flying.

Diversion Procedures

OpSpecs for commercial operators include provisions for en 

route emergency diversion airport requirements. Operators 

are expected to develop a sufficient set of emergency 

diversion airports, so that one or more can be reasonably 

expected to be available in varying weather conditions. 

The flight must be able to make a safe landing, and the 

airplane maneuvered off of the runway at the selected 

diversion airport. In the event of a disabled airplane 

following landing, the capability to move the disabled 

airplane must exist so as not to block the operation of any 

recovery airplane. In addition, those airports designated 

for use must be capable of protecting the safety of all 

personnel by being able to: 

•	 Offload the passengers and flight crew in a safe

manner during possible adverse weather conditions.

•	 Provideforthephysiologicalneedsofthepassengers

and flight crew for the duration until safe evacuation.

•	 Be able to safely extract passengers and flight crew

as soon as possible. Execution and completion of the 

recovery is expected within 12 to 48 hours following 

diversion.

Part 91 operators also need to be prepared for a diversion. 

Designation of an alternate on the IFR flight plan is a good 

first step; but changing weather conditions or equipment 

issues may require pilots to consider other options.
3-1

Introduction

Preparation for the arrival and approach begins long 

before the descent from the en route phase of flight. 

Planning early, while there are fewer demands on the 

pilot’s attention, leaves the pilot free to concentrate on 

precise control of the aircraft and better equipped to deal 

with problems that might arise during the last segment 

of the flight.

Arrivals

Chapter 3
3-2

This chapter focuses on the current procedures pilots and 

air traffic control (ATC) use for instrument flight rule (IFR) 

arrivals in the National Airspace System (NAS). The objective 

is to provide pilots with an understanding of ATC arrival 

procedures and pilot responsibilities as they relate to the 

transition between the en route and approach phases of 

flight. This chapter emphasizes standard terminal arrival 

routes (STARs), descent clearances, descent planning, and 

ATC procedures, while the scope of coverage focuses on 

transitioning from the en route phase of flight, typically 

the origination point of a STAR to the STAR termination fix.

Optimum IFR arrival options include flying directly from the 

en route structure to an approach gate or initial approach 

fix (IAF), a visual arrival, STARs, and radar vectors. Within 

controlled airspace, ATC routinely uses radar vectors for 

separation purposes, noise abatement considerations 

when it is an operational advantage, or when requested by 

pilots. Vectors outside of controlled airspace are provided 

only on pilot request. The controller tells the pilot the 

purpose of the vector when the vector is controller-initiated 

and takes the aircraft off a previously assigned non-radar 

route. Typically, when operating on area navigation 

(RNAV) routes, pilots are allowed to remain on their own 

navigation. 

Navigation in the Arrival Environment

The most significant and demanding navigational 

requirement is the need to safely separate aircraft. In a 

non-radar environment, ATC does not have an independent 

means to separate air traffic and must depend entirely on 

information relayed from flight crews to determine the 

actual geographic position and altitude. In this situation, 

precise navigation is critical to ATC’s ability to provide 

separation.

Even in a radar environment, precise navigation and 

position reports, when required, are still a primary means 

of providing separation. In most situations, ATC does not 

have the capability or the responsibility for navigating 

an aircraft. Because they rely on precise navigation by 

the flight crew, flight safety in all IFR operations depends 

directly on the pilot’s ability to achieve and maintain 

certain levels of navigational performance. ATC uses radar 

to monitor navigational performance, detect possible 

navigational errors, and expedite traffic flow. In a nonradar environment, ATC has no independent knowledge 

of the actual position of the aircraft or its relationship to 

other aircraft in adjacent airspace. Therefore, ATC’s ability 

to detect a navigational error and resolve collision hazards 

is seriously degraded when a deviation from a clearance 

occurs.

The concept of navigation performance, previously 

discussed in this book, involves the precision that must 

be maintained for both the assigned route and altitude. 

Required levels of navigation performance vary from area 

to area depending on traffic density and complexity of 

the routes flown. The level of navigation performance 

must be more precise in domestic airspace than in 

oceanic and remote land areas since air traffic density in 

domestic airspace is much greater. For example, there are 

three million flight operations conducted within Chicago 

Center’s airspace each year. The minimum lateral distance 

permitted between co-altitude aircraft in Chicago Center’s 

airspace is 8 nautical miles (NM) (3 NM when radar is used). 

The route ATC assigns an aircraft has protected airspace 

on both sides of the centerline, equal to one-half of the 

lateral separation minimum standard. For example, the 

overall level of lateral navigation performance necessary for 

flight safety must be better than 4 NM in Center airspace. 

When STARs are reviewed subsequently in this chapter, it is 

demonstrated how the navigational requirements become 

more restrictive in the arrival phase of flight where air traffic 

density increases and procedural design and obstacle 

clearance become more limiting.

The concept of navigational performance is fundamental to 

the code of federal regulations and is best defined in Title

14 of the Code of Federal Regulations (14 CFR) Part 121, 

sections 121.103 and 121.121, which state that each 

aircraft must be navigated to the degree of accuracy 

required for ATC. The requirements of 14 CFR Part 91, 

section 91.123 related to compliance with ATC clearances 

and instructions also reflect this fundamental concept. 

Commercial operators must comply with their Operations 

Specifications (OpSpecs) and understand the categories 

of navigational operations and be able to navigate to the 

degree of accuracy required for the control of air traffic.

In the broad concept of air navigation, there are two major 

categories of navigational operations consisting of Class 

I navigation and Class II navigation. Class I navigation is 

any en route flight operation conducted in controlled or 

uncontrolled airspace that is entirely within operational 

service volumes of International Civil Aviation Organization 

(ICAO) standard navigational aids (NAVAIDs) (very high 

frequency (VHF) omnidirectional radio range (VOR), VOR/

distance measuring equipment (DME), non-directional 

beacon (NDB), etc.).

Class II navigation is any en route operation that is not 

categorized as Class I navigation and includes any operation 

or portion of an operation that takes place outside the 

operational service volumes of ICAO standard NAVAIDs. 

For example, aircraft equipped only with VORs conducts 
3-3

Figure 3-1. Example of Class I and II navigation.

CLASS I

CLASS I

CLASS I

CLASS I

CLASS I

CLASS I

VORTAC A VORTAC B

Route 1

Route 2

CLASS II

1 hour or less

CLASS II

more than 1 hour

Route 3

The area encompassed by the cylinders represents the volume of airspace within the operational service volume 

(OSV) of ICAO standard NAVAIDs. The altitude of your aircraft with respect to the location of the NAVAID is a

primary factor in determining OSV range.” 

Your aircraft navigating from A to B is conducting Class I navigation because you remain within the OSV of 

ICAO standard NAVAIDs during your entire flight.

Your aircraft navigating from A to B is conducting Class I navigation while within the OSV of the NAVAIDs.

You are conducting Class II navigation during the portion of your route outside the OSV of the NAVAIDs.

Because the duration of the Class II navigation is 1 hour or less, long-range navigation equipment or a flight 

navigator may not be required.

Your aircraft navigating from A to B is conducting Class I navigation while within the OSV of the NAVAIDs.

You are conducting Class II navigation when outside the OSV of the NAVAIDs. The duration of the Class II 

navigation is more than 1 hour. Therefore, long-range navigation equipment or a flight navigator is required. 

NOTE:

Route 1

Route 2

Route 3

Class II navigation when the flight operates in an area 

outside the operational service volumes of federal VORs. 

Class II navigation does not automatically require the 

use of long-range, specialized navigational systems if 

special navigational techniques are used to supplement 

conventional NAVAIDs. Class II navigation includes 

transoceanic operations and operations in desolate and 

remote land areas, such as the Arctic. The primary types 

of specialized navigational systems approved for Class II 

operations include inertial navigation system (INS), Doppler, 

and global positioning system (GPS). Figure 3-1 provides 

several examples of Class I and II navigation.

Descent Planning

Planning the descent from cruise is important because of 

the need to dissipate altitude and airspeed in order to arrive 

at the approach gate properly configured. Descending early 

results in more flight at low altitudes with increased fuel 

consumption, and starting down late results in problems 

controlling both airspeed and descent rates on the 

approach. Prior to flight, pilots need to calculate the fuel, 

time, and distance required to descend from the cruising 

altitude to the approach gate altitude for the specific 

instrument approach at the destination airport. While 

in flight prior to the descent, it is important for pilots to 

verify landing weather to include winds at their intended 

destination. Inclimate weather at the destination airport can 

cause slower descents and missed approaches that require 

a sufficient amount of fuel that should be calculated prior to 

starting the descent. In order to plan the descent, the pilot 

needs to know the cruise altitude, approach gate altitude 

or initial approach fix altitude, descent groundspeed, and 
3-4

Figure 3-2. VNAV path construction.

VNAV begins at the runway 

waypoint constraint altitude

(E/D) and then follows the 

vertical angle upstream.

1

The path is computed beginning 

from the E/D constraint (and 

vertical angle) to the next 

constraint that “gets in the way”

(at 4,000' in this drawing) and

then to the next constraint, and

so on.

2

VNAV plans for 

decelerations to

honor speed 

restrictions, e.g.

250 knots below 

10,000'

(monotonic 

decelerations).

3

From last 

constraint to T/D,

path is computed 

using available 

performance data

to achieve an 

ECON efficient 

path.

4

3°

Top-of-descent

Instrument approach vertical angle

coded in the navigation database

Between 12,000' and 10,000'

At or below 8,000' 220 kt max

At or above 2,200'

At 4,000'

descent rate. This information must be updated while 

in flight for changes in altitude, weather, and wind. The 

approach gate is an imaginary point used by ATC to vector 

aircraft to the final approach course. The approach gate 

is established along the final approach course 1 NM from 

the final approach fix (FAF) on the side away from the 

airport and is located no closer than 5 NM from the landing 

threshold. Flight manuals or operating handbooks may also 

contain a fuel, time, and distance to descend chart that 

contains the same information.

One technique that is often used is the descent rule of 

thumb, which is used to determine when you need to 

descend in terms of the number of miles prior to the point 

at which you desire to arrive at your new altitude. First, 

divide the altitude needed to be lost by 300. For example, 

if cruising altitude is 7,000 feet and you want to get down 

to a pattern altitude of 1,000 feet. The altitude you want to 

lose is 6,000 feet, which when divided by 300 results in 20. 

Therefore, you need to start your descent 20 NM out and 

leave some extra room so that you are at pattern altitude 

prior to the proper entry. It is also necessary to know what 

rate-of-descent (ROD) to use.

To determine ROD for a three-degree path, simply multiply 

your groundspeed by 5. If you are going 120 knots, your ROD 

to fly the desired path would be 600 feet per minute (120 

× 5 = 600). It was determined in the previous example that 

a descent should be initiated at 20 NM to lose 6,000 feet. 

If the groundspeed is 120 knots, that means the aircraft is 

moving along at 2 NM per minute. So to go 20 NM, it takes

10 minutes. Ten minutes at 600 feet per minute means you

will lose 6,000 feet.

The calculations should be made before the flight and rules 

of thumb updates should be applied in flight. For example,

from the charted STAR pilots might plan a descent based on 

an expected clearance to “cross 40 DME West of Brown VOR 

at 6,000” and then apply rules of thumb for slowing down 

from 250 knots. These might include planning airspeed at 25

NM from the runway threshold to be 250 knots, 200 knots at

20 NM, and 150 knots at 15 NM until gear and flap speeds 

are reached, never to fall below approach speed.

Vertical Navigation (VNAV) Planning

Vertical navigation (VNAV) is the vertical component of 

the flight plan. This approach path is computed from the 

top-of- descent (TOD) point down to the end-of-descent 

waypoint (E/D), which is generally the runway or missed 

approach point, which is slightly different than to the 

approach gate for non-flight management system (FMS) 

equipped aircraft. [Figure 3-2] The VNAV path is computed 

based upon the aircraft performance, approach constraints, 

weather data (winds, temperature, icing conditions, etc.) 

and aircraft weight.
3-5

Figure 3-3. VNAV performance path.

Top-of-descent

Idle descent path at ECON speed

NEEAL

5000

BUCKK

2200

Computed descent path at idle (or near-idle) power 

from top-of-descent to the first constrained waypoint

Performance Path

Figure 3-4. VNAV geometric path.

Top-of-descent

Idle descent path at ECON speed

Geometric paths at VNAV target speed

NEEAL

5000

OLM

12,000

BUCKK

2200

Computed 3-D point-to-point descent path between

two constrained waypoints or when tracking a 

prescribed vertical angle

The geometric path is a shallower descent and 

typically a non-idle path.

Geometric Path

3°

3°
3-6

Figure 3-5. WAAS data provide lateral and vertical guidance.

GPS ENR

FLAGGED

119.000

121.600

114.10

116.00

1200

A 

C 

T

A 

C 

T

S 

B 

Y

S 

B 

Y

S 

B 

Y

--.- vor

MSG PROC FPL NAV

GS ETE

DIST BRG

120kt 04:52

9.74 n

m TRK 332° 332°

Lnav/Vnav C345 SUNOL RW34Lm

DTK

346°

This GPS/RNAV provides lateral and vertical 

guidance during an RNAV approach.

The two types of VNAV paths that the FMS use is either a 

performance path or a geometric path. The performance 

path is computed using at idle or near idle power from 

the TOD to the first constrained waypoint. [Figure 3-3] 

The geometric path is computed from point to point 

between two constrained waypoints or when on an 

assigned vertical angle. The geometric path is shallower 

than the performance path and is typically a non-idle 

path. [Figure 3-4]

LNAV/VNAV Equipment

Lateral navigation/vertical navigation (LNAV/VNAV) 

equipment is similar to an instrument landing system (ILS) 

in that it provides both lateral and vertical approach course 

guidance. Since precise vertical position information is 

beyond the current capabilities of the GPS, approaches with 

LNAV/VNAV minimums make use of certified barometric 

VNAV (baro-VNAV) systems for vertical guidance and/or 

the wide area augmentation system (WAAS) to improve 

GPS accuracy for this purpose.

NOTE: WAAS makes use of a collection of ground stations 

that are used to detect and correct inaccuracies in the 

position information derived from the GPS. Using WAAS, 

the accuracy of vertical position information is increased 

to within three meters.

To make use of WAAS, however, the aircraft must be 

equipped with an IFR-approved GPS receiver with WAAS 

signal reception that integrates WAAS error correction 

signals into its position determining processing. The WAAS 

enabled GPS receiver [Figure 3-5] allows the pilot to load an 

RNAV approach and receive guidance along the lateral and 

vertical profile shown on the approach chart. [Figure 3-6]

It is very important to know what kind of equipment is 

installed in an aircraft, and what it is approved to do. It is 

also important to understand that the VNAV function of 

non-WAAS capable or non-WAAS equipped IFR-approved 

GPS receivers does not make the aircraft capable of flying 

approaches to LNAV/VNAV minimums.

FMS are the primary tool for most modern aircraft, air 

carriers, and any operators requiring performance based 

navigation. Most of the modern FMS are fully equipped 

with LNAV/VNAV and WAAS. The FMS provides flight control

steering and thrust guidance along the VNAV path. Some 

less integrated systems may only advise the flight crew 

of the VNAV path but have no auto-throttle capability. 

These less integrated systems require an increase in pilot 

workload during the arrival/approach phase in order to 

maintain the descent path.

Descent Planning for High Performance Aircraft

The need to plan the IFR descent into the approach gate 

and airport environment during the preflight planning 

stage of flight is particularly important for turbojet 

powered airplanes. TOD from the en route phase of flight 

for high performance airplanes is often used in this process 

and is calculated manually or automatically through a FMS 

based upon the altitude of the approach gate. A general 

rule of thumb for initial IFR descent planning in jets is the 

3 to 1 formula. This means that it takes 3 nautical miles 

(NM) to descend 1,000 feet. If an airplane is at flight level 

(FL) 310 and the approach gate or initial approach fix is at 

6,000 feet, the initial descent requirement equals 25,000 

feet (31,000–6,000). Multiplying 25 times 3 equals 75; 

therefore begin descent 75 NM from the approach gate, 

based on a normal jet airplane, idle thrust, speed Mach 

0.74 to 0.78, and vertical speed of 1,800–2,200 feet per 

minute (fpm). For a tailwind adjustment, add 2 NM for each 

10 knots of tailwind. For a headwind adjustment, subtract 

2 NM for each 10 knots of headwind. During the descent 

planning stage, try to determine which runway is in use at 

the destination airport, either by reading the latest aviation 

routine weather report (METAR) or checking the automatic 

terminal information service (ATIS) information. There can 

be big differences in distances depending on the active 

runway and STAR. The objective is to determine the most 

economical point for descent. 

An example of a typical jet descent-planning chart is 

depicted in Figure 3-7. Item 1 is the pressure altitude from 

which the descent begins; item 2 is the time required 

for the descent in minutes; item 3 is the amount of fuel 

consumed in pounds during descent to sea level; and 

item 4 is the distance covered in NM. Item 5 shows that 

the chart is based on a Mach .80 airspeed until 280 knots 
3-7

Figure 3-6. RNAV (GPS) approach. NE-4, 21 OCT 2010 to 18 NOV 2010

NE-4, 21 OCT 2010 to 18 NOV 2010

NOT FOR NAVIGATION
3-8

Figure 3-7. Jet descent task.

Pressure Altitude 

(1,000 feet)

Note: Subtract 30 lb of fuel and 36 seconds for each 

1,000 feet that the destination airport is above sea level

Time

(minutes)

Fuel

(pounds)

Distance

(NM)

39

37

35

33

31

29

27

25

23

21

19

17

15

10

5

20

19

18

17

16

15

14

13

12

11

10

10

9

6

3

850

800

700

650

600

600

550

550

500

500

450

450

400

300

150

124

112

101

92

86

80

74

68

63

58

52

46

41

26

13

NOTE:

.80/280

SAMPLE NOT FOR ACTUAL USE 

5 2 3 4 1

Figure 3-8. The descent planning task.

Wind

Top-of-descent point

Bottom-of-descent point

ECA VOR

Cruising altitude ft 1 1 0 0 0

Assigned altitude ft 3 0 0 0

Cruising speed knots 2 7 0

Descent speed and rate

1 8 0 knots @ 1,000 fpm

indicated airspeed (KIAS) is obtained. The 250 knot airspeed 

limitation below 10,000 feet mean sea level (MSL) is not 

included on the chart, since its effect is minimal. Also, the 

effect of temperature or weight variation is negligible and 

is therefore omitted. 

Due to the increased flight deck workload, pilots should 

get as much done ahead of time as possible. As with the 

climb and cruise phases of flight, aircrews should consult 

the proper performance charts to compute their fuel 

requirements, as well as the time and distance needed for 

their descent.

During the cruise and descent phases of flight, pilots 

need to monitor and manage the airplane according to 

the appropriate manufacturer’s recommendations. Flight 

manuals and operating handbooks contain cruise and 

descent checklists, performance charts for specific cruise 

configurations, and descent charts that provide information 

regarding the fuel, time, and distance required to descend. 

Aircrews should review this information prior to the 

departure of every flight so they have an understanding 

of how the airplane is supposed to perform at cruise 

and during descent. A stabilized descent constitutes a 

preplanned maneuver in which the power is properly set, 

and minimum control input is required to maintain the 

appropriate descent path. Excessive corrections or control 

inputs indicate the descent was improperly planned. Plan 

the IFR descent from cruising altitude so that the aircraft 

arrives at the approach gate altitude or initial approach 

fix altitude prior to beginning the instrument approach. 

For example, suppose you are asked to descend from 

11,000 feet to meet a crossing restriction at 3,000 feet. 

[Figure 3-8] Since there is a 200 knot speed restriction 

while approaching the destination airport, you choose a 

descent speed of 190 knots and a descent rate of 1,000 fpm. 

Assuming a 10 knot headwind component, groundspeed 

in the descent is 180 knots. 

Descending From the En Route Altitude

Making the transition from cruise flight to the beginning 

of an instrument approach procedure sometimes requires 

arriving at a given waypoint at an assigned altitude. When 

this requirement is prescribed by a published arrival 
3-9

procedure or issued by ATC, it is called a crossing restriction. 

Even when ATC allows a descent at the pilot’s discretion, 

aircrews need to choose a waypoint and altitude for 

positioning convenient to start the approach. In either case, 

descending from a cruising altitude to a given waypoint or 

altitude requires both planning and precise flying.

ATC may ask the pilot to descend to and maintain a 

specific altitude. Generally, this clearance is for en route 

traffic separation purposes, and pilots need to respond to 

it promptly. Descend at the optimum rate for the aircraft 

being flown until 1,000 feet above the assigned altitude, 

then descend at a rate between 500 and 1,500 fpm to the 

assigned altitude. If at any time, other than when slowing 

to 250 KIAS at 10,000 feet MSL, the pilot cannot descend 

at a rate of at least 500 fpm, advise ATC.

The second type of clearance allows the pilot to descend 

“... at pilot’s discretion.” When ATC issues a clearance to 

descend at pilot’s discretion, pilots may begin the descent 

whenever they choose and at any rate of their choosing. 

Pilots are also authorized to level off, temporarily, at any 

intermediate altitude during the descent. However, once 

the aircraft leaves an altitude, it may not return to that 

altitude.

A descent clearance may also include a segment where the 

descent is at the pilots’ discretion—such as “cross the Joliet 

VOR at or above 12,000, descend and maintain 5,000.” This 

clearance authorizes pilots to descend from their current 

altitude whenever they choose, as long as they cross the 

Joliet VOR at or above 12,000 feet MSL. After that, they are 

expected to descend at a normal rate until they reach the 

assigned altitude of 5,000 feet MSL.

Clearances to descend at pilots’ discretion are not just an 

option for ATC. Pilots may also request this type of clearance 

so that they can operate more efficiently. For example, if 

a pilot was en route above an overcast layer, he or she 

might ask for a descent at his or her discretion to allow the 

aircraft to remain above the clouds for as long as possible. 

This might be particularly important if the atmosphere 

is conducive to icing and the aircraft’s icing protection 

is limited. The pilot’s request permits the aircraft to stay 

at its cruising altitude longer to conserve fuel or to avoid 

prolonged IFR flight in icing conditions. This type of descent 

can also help to minimize the time spent in turbulence by 

allowing pilots to level off at an altitude where the air is 

smoother.

Controlled Flight Into Terrain (CFIT)

Inappropriate descent planning and execution during 

arrivals has been a contributing factor to many fatal 

aircraft accidents. Since the beginning of commercial jet 

operations, more than 9,000 people have died worldwide 

because of controlled flight into terrain (CFIT). CFIT is 

described as an event in which a normally functioning 

aircraft is inadvertently flown into the ground, water, or an 

obstacle. Of all CFIT accidents, 7.2 percent occurred during 

the descent phase of flight.

The basic causes of CFIT accidents involve poor flight 

crew situational awareness (SA). One definition of SA is an 

accurate perception by pilots of the factors and conditions 

currently affecting the safe operation of the aircraft and the 

crew. The causes of CFIT are the flight crews’ lack of vertical 

position awareness or their lack of horizontal position 

awareness in relation to the ground, water, or an obstacle. 

More than two-thirds of all CFIT accidents are the result 

of an altitude error or lack of vertical SA. CFIT accidents 

most often occur during reduced visibility associated with 

instrument meteorological conditions (IMC), darkness, or 

a combination of both.

The inability of controllers and pilots to properly 

communicate has been a factor in many CFIT accidents. 

Heavy workloads can lead to hurried communication and 

the use of abbreviated or non-standard phraseology. The 

importance of good communication during the arrival 

phase of flight was made evident in a report by an air traffic 

controller and the flight crew of an MD-80.

The controller reported that he was scanning his radarscope 

for traffic and noticed that the MD-80 was descending 

through 6,400 feet. He immediately instructed a climb 

to at least 6,500 feet. The pilot returned to 6,500 feet, but 

responded to ATC that he had been cleared to 5,000 feet. 

When he had read back 5,000 feet to the controller, he 

received no correction from the controller. After almost 

simultaneous ground proximity warning system (GPWS) 

and controller warnings, the pilot climbed and avoided 

the terrain. The recording of the radio transmissions 

confirmed that the airplane was cleared to 7,000 feet and 

the pilot mistakenly read back 5,000 feet then attempted 

to descend to 5,000 feet. The pilot stated in the report: “I 

don’t know how much clearance from the mountains we 

had, but it certainly makes clear the importance of good 

communications between the controller and pilot.”

ATC is not always responsible for safe terrain clearance for 

the aircraft under its jurisdiction. Many times ATC issue en 

route clearances for pilots to proceed off airway direct to 

a point. Pilots who accept this type of clearance also are 

accepting the shared responsibility for maintaining safe 

terrain clearance. Know the height of the highest terrain 

and obstacles in the operating area and your position in 

relation to the surrounding high terrain.
3-10

Figure 3-9. Altitude management when cleared direct.

“I need to check my altitude requirement.”

“....cleared present position direct.....”

The following are excerpts from CFIT accidents related 

to descending on arrival: “...delayed the initiation of the 

descent...”; “Aircraft prematurely descended too early...”; 

“...late getting down...”; “During a descent...incorrectly 

cleared down...”; “...aircraft prematurely let down...”; 

“...lost situational awareness...”; “Premature descent 

clearance...”; “Prematurely descended...”; “Premature 

descent clearance while on vector...”; “During initial 

descent...” [Figure 3-9]

Practicing good communication skills is not limited to just 

pilots and controllers. In its findings from a 1974 air carrier 

accident, the National Transportation Safety Board (NTSB) 

wrote, “...the extraneous conversation conducted by the 

flight crew during the descent was symptomatic of a lax 

atmosphere in the flight deck that continued throughout 

the approach.” The NTSB listed the probable cause as “... 

the flight crew’s lack of altitude awareness at critical points 

during the approach due to poor flight deck discipline in 

that the crew did not follow prescribed procedures.”

In 1981, the FAA issued 14 CFR Part 121, section 121.542 

and Part 135, section 135.100, Flight Crewmember Duties, 

commonly referred to as “sterile flight deck rules.” The 

provisions in this rule can help pilots, operating under any 

regulations, to avoid altitude and course deviations during 

arrival. In part, it states: (a) No certificate holder should 

require, nor may any flight crewmember perform, any 

duties during a critical phase of flight except those duties 

required for the safe operation of the aircraft. Duties such as 

company required calls made for such purposes as ordering 

galley supplies and confirming passenger connections, 

announcements made to passengers promoting the air 

carrier or pointing out sights of interest, and filling out 

company payroll and related records are not required for 

the safe operation of the aircraft. (b) No flight crewmember 

may engage in, nor may any pilot in command permit, any 

activity during a critical phase of flight that could distract 

any flight crewmember from the performance of his or her 

duties or which could interfere in any way with the proper 

conduct of those duties. Activities such as eating meals, 

engaging in nonessential conversations within the flight 

deck and nonessential communications between the cabin 

and flight deck crews, and reading publications not related 

to the proper conduct of the flight are not required for the 

safe operation of the aircraft. (c) Critical phases of flight 

include all ground operations involving taxi, takeoff and 

landing, and all other flight operations conducted below 

10,000 feet, except cruise flight.

Standard Terminal Arrival Routes 

(STARs)

A STAR is an ATC-coded IFR route established for application 

to arriving IFR aircraft destined for certain airports. A STAR 

provides a critical form of communication between pilots 

and ATC. Once a flight crew has accepted a clearance for a 

STAR, they have communicated with the controller what 

route, and in some cases what altitude and airspeed, they 

fly during the arrival, depending on the type of clearance. 

The STAR provides a common method for leaving the en 

route structure and navigating to your destination. It is a 

preplanned instrument flight rule ATC arrival procedure 

published for pilot use in graphic and textual form that 

simplifies clearance delivery procedures.

The principal difference between standard instrument 

departure (SID) or departure procedures (DPs) and STARs 

is that the DPs start at the airport pavement and connect 

to the en route structure. STARs on the other hand, start 

at the en route structure but do not make it down to the 

pavement; they end at a fix or NAVAID designated by ATC, 

where radar vectors commonly take over. This is primarily 
3-11

Figure 3-10. Arrival charts.

SW-3, 21 OCT 2010 to 18 NOV 2010

SW-3, 21 OCT 2010 to 18 NOV 2010

0102 VON81 ot 0102 TCO12, 2- EN

NOT FOR NAVIGATION

NE-2, 21 OCT 2010 to 18 NOV 2010
3-12

because STARs serve multiple airports. STARs greatly help to 

facilitate the transition between the en route and approach 

phases of flight. The objective when connecting a STAR to 

an instrument approach procedure is to ensure a seamless 

lateral and vertical transition. The STAR and approach 

procedure should connect to one another in such a way as 

to maintain the overall descent and deceleration profiles. 

This often results in a seamless transition between the en 

route, arrival, and approach phases of flight, and serves as 

a preferred route into high volume terminal areas. [Figure 

3-10]

STARs provide a transition from the en route structure to an 

approach gate, outer fix, instrument approach fix, or arrival 

waypoint in the terminal area, and they usually terminate 

with an instrument or visual approach procedure. STARs 

are included at the front of each Terminal Procedures 

Publication (TPP) regional booklet.

For STARs based on conventional NAVAIDs, the procedure 

design and obstacle clearance criteria are essentially the 

same as that for en route criteria, covered in Chapter 2, 

En Route Operations. STAR procedures typically include a 

standardized descent gradient at and above 10,000 feet MSL 

of 318 feet per nautical mile (FPNM), or 3 degrees. Below 

10,000 feet MSL, the maximum descent rate is 330 FPNM, 

or approximately 3.1 degrees. In addition to standardized 

descent gradients, STARs allow for deceleration segments 

at any waypoint that has a speed restriction. As a general 

guideline, deceleration considerations typically add 1 NM 

of distance for each 10 knots of speed reduction required.

RNAV STARs or STAR Transitions

STARs designated RNAV serve the same purpose as 

conventional STARs, but are only used by aircraft equipped 

with FMS or GPS. An RNAV STAR or STAR transition typically 

includes flyby waypoints, with fly over waypoints used 

only when operationally required. These waypoints may 

be assigned crossing altitudes and speeds to optimize 

the descent and deceleration profiles. RNAV STARs often 

are designed, coordinated, and approved by a joint effort 

between air carriers, commercial operators, and the ATC 

facilities that have jurisdiction for the affected airspace.

RNAV STAR procedure design, such as minimum leg 

length, maximum turn angles, obstacle assessment criteria, 

including widths of the primary and secondary areas, use 

the same design criteria as RNAV DPs. Likewise, RNAV STAR 

procedures are designated as either RNAV-1 or RNAV2, based on the aircraft navigation equipment required, 

flight crew procedures, and the process and criteria used 

to develop the STAR. The RNAV-1 or RNAV-2 designation 

appears in the notes on the chart. RNAV-1 STARs have 

higher equipment requirements and, often, tighter 

required navigation performance (RNP) tolerances than 

RNAV-2. For RNAV-1 STARS, pilots are required to use a 

course deviation indicator (CDI)/flight director, and/or 

autopilot in LNAV mode while operating on RNAV courses. 

(These requirements are detailed in Chapter 1 of this book, 

under RNAV Departures.) RNAV-1 STARs are generally 

designated for high-traffic areas. Controllers may clear a 

pilot to use an RNAV STAR in various ways.

If the pilots clearance simply states, “cleared Hadly One 

arrival,” the pilot is to use the arrival for lateral routing only.

•	 A clearance such as “cleared Hadly One arrival,

descend and maintain flight level two four zero,” 

clears the pilot to descend only to the assigned 

altitude, and then should maintain that altitude until 

cleared for further VNAV. 

•	 If the pilot is cleared using the phrase“descend via,”

the controller expects the pilot to use the equipment 

for both lateral and VNAV, as published on the chart.

•	 The controller may also clear the pilot to use the

arrival with specific exceptions—for example, 

“Descend via the Haris One arrival, except cross 

Bruno at one three thousand then maintain one 

zero thousand.” In this case, the pilot should track the 

arrival both laterally and vertically, descending so as 

to comply with all altitude and airspeed restrictions 

until reaching Bruno, and then maintain 10,000 feet 

until cleared by ATC to continue to descend.

•	 Pilots might also be given directrouting to intercept

a STAR and then use it for VNAV. For example, 

“Proceed direct Mahem, descend via the Mahem 

Two arrival.”

Interpreting the STAR

STARs use much of the same symbology as departure and 

approach charts. In fact, a STAR may at first appear identical 

to a similar graphic DP, except the direction of flight is 

reversed and the procedure ends at an approach fix. The 

STAR officially begins at the common NAVAID, intersection, 

or fix where all the various transitions to the arrival come 

together. A STAR transition is a published segment used to 

connect one or more en route airways, jet routes, or RNAV 

routes to the basic STAR procedure. It is one of several 

routes that bring traffic from different directions into one 

STAR. This way, arrivals from several directions can be 

accommodated on the same chart, and traffic flow is routed 

appropriately within the congested airspace.

To illustrate how STARs can be used to simplify a complex 

clearance and reduce frequency congestion, consider 
3-13

Figure 3-11. STAR interpretation.

1102 RPA 70 ot 1102 RA M01, 1- WN

NW-1, 10 MAR 2011 to 07 APR 2011

NOT FOR NAVIGATION

CHINS

RADDY

The STAR does not depict terrain 

information. You must look at World 

Aeronautical Charts (WACs) or

sectional charts to get a feel for the

underlying topography.

The primary arrival airport is SeattleTacoma International. Other airports 

may be served by the procedure, such as

Boeing Field/King County International.

Radar vectors lead from the 

arrival to either a north or 

south nal approach course.

The STAR helps controllers manage the ow 

of trac into a busy terminal area during 

periods of delays due to weather. The hold at 

RADDY Intersection often serves this purpose.

Lost communication procedures are included when needed for obstacle 

clearance. Otherwise, follow the standard lost communication procedure.

If the en route portion of your ight ends at the 

Kimberly VOR, you should add the Kimberly 

Transition to the end of the route description 

of your ight plan.

The CHINS SEVEN

ARRIVAL starts at 

CHINS Intersection.

STARs include the name 

of the procedure title.

the following arrival clearance issued to a pilot flying to 

Seattle, Washington, depicted in Figure 3-11: “Cessna 32G, 

cleared to the Seattle/Tacoma International Airport as filed. 

Maintain 12,000. At the Ephrata VOR, intercept the 221° 

radial to CHINS Intersection. Intercept the 284° radial of the 

Yakima VOR to RADDY Intersection. Cross RADDY at 10,000. 

Continue via the Yakima 284° radial to AUBRN Intersection. 

Expect radar vectors to the final approach course.”

Now consider how this same clearance is issued when a 

STAR exists for this terminal area. “Cessna 32G, cleared to 

Seattle/Tacoma International Airport as filed, then CHINS 

EIGHT ARRIVAL, Ephrata Transition. Maintain 10,000 feet.” A 

shorter transmission conveys the same information.

Safety is enhanced when both pilots and controllers know 

what to expect. Effective communication increases with the 
3-14

Figure 3-12. Reducing pilot/controlling workload.

SW-2, 21 OCT 2010 ot 18 NOV 2010

SW-2, 21 OCT 2010 to 18 NOV 2010

NOT FOR NAVIGATION
3-15

Figure 3-13. STAR symbology.

0102 VON81 ot 0102 TCO12, 2- EN

NE-2, 21 OCT 2010 to 18 NOV 2010

0102 VON81 ot 0102 TCO12, 2- EN

NE-2, 21 OCT 2010 to 18 NOV 2010

NOT FOR NAVIGATION

All altitudes on the chart are MSL and 

distances are in nautical miles. The MEA 

for this route segment is 6,000 feet MSL, and 

its length is 35 nautical miles.

Each transition is named for its

point of origin. All transitions

come together at Pawling VOR,

the beginning of the actual STAR.

Frequency data is given in

a corner of the chart. Note

that ATIS frequencies for all

airports served are shown.

You need not fly into JFK to use

this STAR. Republic Airport in

Farmingdale is also served.

Arrival charts are most often not to

scale due to the distribution of

important fixes along the route.

If the en route portion of your flight ends

at Rockdale VOR, you enter this

transition on your IFR flight plan as

RKA.PWL2. Notice that, as opposed to a

DP, the transition name is stated first,

then the arrival name.

From the Albany VOR, the transition follows the 194° 

radial to the ATHOS Intersection. From ATHOS, the 

transition follows the 354° radial to the Pawling VOR, 

where it joins the STAR.

reduction of repetitive clearances, decreasing congestion 

on control frequencies. To accomplish this, STARs are 

developed according to the following criteria: 

• 	 STARs must be simple, easily understood and, if

possible, limited to one page. 

• 	 ASTAR transition shouldbe able to accommodate as

many different types of aircraft as possible. 

• 	 VHFOmnidirectional Range/TacticalAircraftControl

(VORTACs) are used wherever possible, with some 

exceptions on RNAV STARs, so that military and 

civilian aircraft can use the same arrival. 

• 	 DME arcs within a STAR should be avoided since

not all aircraft operating under IFR are equipped to 

navigate them. 

• 	 Altitude crossing and airspeed restrictions are

included when they are assigned by ATC a majority 

of the time. [Figure 3-12]

STARs usually are named according to the point at which 

the procedure begins. In the United States, typically there 

are en route transitions before the STAR itself. So the STAR 

name is usually the same as the last fix on the en route 

transitions where they come together to begin the basic 

STAR procedure. A STAR that commences at the CHINS 

Intersection becomes the CHINS SEVEN ARRIVAL. When a 
3-16

significant portion of the arrival is revised, such as an altitude, 

a route, or data concerning the NAVAID, the number of the 

arrival changes. For example, the CHINS SEVEN ARRIVAL is 

now the CHINS EIGHT ARRIVAL due to modifications in the 

procedure.

Studying the STARs for an airport may allow pilots to perceive 

the specific topography of the area. Note the initial fixes and 

where they correspond to fixes on the National Aeronautical 

Navigational Products (AeroNav Products) en route or area 

chart. Arrivals may incorporate step-down fixes when 

necessary to keep aircraft within airspace boundaries or 

for obstacle clearance. Routes between fixes contain 

courses, distances, and minimum altitudes, alerting aircrews 

to possible obstructions or terrain under their arrival 

path. Airspeed restrictions also appear where they aid in 

managing the traffic flow. In addition, some STARs require 

that pilots use DME and/or ATC radar. Aircrews can decode 

the symbology on the PAWLING TWO ARRIVAL by referring 

to the legend at the beginning of the TPP. [Figure 3-13]

STAR Procedures

Pilots may accept a STAR within a clearance or they may 

file for one in their flight plan. As the aircraft nears its 

destination airport, ATC may add a STAR procedure to 

its original clearance. Keep in mind that ATC can assign 

a STAR even if the aircrew has not requested one. Use of 

a STAR requires pilot possession of at least the approved 

chart. RNAV STARs must be retrievable by the procedure 

name from the aircraft database and conform to charted 

procedure. If an aircrew does not want to use a STAR, they 

must specify “No STAR” in the remarks section of their flight 

plan. Pilots may also refuse the STAR when it is given to 

them verbally by ATC, but the system works better if the 

aircrew advises ATC ahead of time.

Preparing for the Arrival

As mentioned before, STARs include navigation fixes that 

are used to provide transition and arrival routes from 

the en route structure to the final approach course. They 

also may lead to a fix where radar vectors are provided 

to intercept the final approach course. Pilots may have 

noticed that minimum crossing altitudes and airspeed 

restrictions appear on some STARs. These expected 

altitudes and airspeeds are not part of the clearance until 

ATC includes them verbally. A STAR is simply a published 

routing; it does not have the force of a clearance until 

issued specifically by ATC. For example, minimum en route 

altitude (MEAs) printed on STARs are not valid unless stated 

within an ATC clearance or in cases of lost communication. 

After receiving the arrival clearance, the aircrew should 

review the assigned STAR procedure and ensure the FMS 

has the appropriate procedure loaded (if so equipped).

Obtain the airport and weather information as early 

as practical. It is recommended that pilots have this 

information prior to flying the STAR. If you are landing at 

an airport with approach control services that has two or 

more published instrument approach procedures, you will 

receive advance notice of which instrument approaches to 

expect. This information is broadcast either by ATIS or by a 

controller. [Figure 3-14] It may not be provided when the 

visibility is 3 statute miles (SM) or better and the ceiling is at 

or above the highest initial approach altitude established 

for any instrument approach procedure for the airport.

For STAR procedures charted with radar vectors to the 

final approach, look for routes from the STAR terminating 

fixes to the IAF. If no route is depicted, you should have 

a predetermined plan of action to fly from the STAR 

terminating fix to the IAF in the event of a communication 

failure. 

Reviewing the Approach

Once the aircrew has determined which approach to 

expect, review the approach chart thoroughly before 

entering the terminal area. Aircrews should check fuel level 

and make sure a prolonged hold or increased headwinds 

have not cut into the aircraft’s fuel reserves because there is 

always a chance the pilot has to make a missed approach or 

go to an alternate. By completing landing checklists early, 

aircrews can concentrate on the approach.

In setting up for the expected approach procedure when 

using an RNAV, GPS, or FMS system, it is important to 

understand how multiple approaches to the same runway 

are coded in the database. When more than one RNAV 

procedure is issued for the same runway, there must be a 

way to differentiate between them within the equipment’s 

database, as well as to select which procedure is to be 

used. (Multiple procedures may exist to accommodate GPS 

receivers and FMS, both with and without VNAV capability.) 

Each procedure name incorporates a letter of the alphabet, 

starting with Z and working backward through Y, X, W, and 

so on. (Naming conventions for approaches are covered in 

more depth in the next chapter). [Figure 3-15]

Altitude 

Upon arrival in the terminal area, ATC either clears the 

aircraft to a specific altitude, or they give it a “descend 

via” clearance that instructs the pilot to follow the 

altitudes published on the STAR. [Figure 3-16] Pilots are 

not authorized to leave their last assigned altitude unless 

specifically cleared to do so. If ATC amends the altitude or 

route to one that is different from the published procedure, 

the rest of the charted descent procedure is cancelled. ATC 

assigns any further route, altitude, or airspeed clearances, 

as necessary. Notice the JANESVILLE FOUR ARRIVAL depicts 

only one published arrival route, with no named transition 
3-17

Figure 3-14. Arrival clearance.

NE-1, 21 OCT 2010 to 18 NOV 2010

NE-1, 21 OCT 2010 to 18 NOV 2010

NOT FOR NAVIGATION

"Piper 52 Sierra, cleared to Logan

International via the GARDNER THREE

ARRIVAL, Albany Transition, maintain 9,000."

At REVER Intersection, you fly 

inbound to the Boston VOR on 

the 030° radial.

The textual description indicates 

different altitude and airspeed 

restrictions for turbojet and nonturbojet aircraft.

At this point, you join the

STAR on the 111° radial 

from Gardner VOR.

You need to change VOR frequencies at the mileage 

breakdown point. Follow the 110° radial from Albany 

VOR to 23 DME, then change to the 294° radial off

of the Gardner VOR.

This note indicates that you can expect radar 

vectors to the final approach course. Have a

plan of action in the event of a communication

failure.
3-18

Figure 3-15. Two RNAV (GPS) approaches to Runway 15R at Baltimore. A controller issuing a clearance for one of these approaches 

would speak the identifying letter—for example, “...cleared for the RNAV (GPS) Yankee approach, Runway 15R...”

NE-3, 21 O

O

V 2010

NOT FOR

NAVIGATION

routes leading to the basic STAR procedure beginning at the 

Janesville VOR/DME. VNAV planning information is included 

for turbojet and turboprop airplanes at the bottom of the 

chart. Additionally, note that there are several ways to 

identify the BRIBE reporting point using alternate formation 

radials, some of which are from off- chart NAVAIDs. ATC may 

issue a descent clearance that includes a crossing altitude 

restriction. In the PENNS ONE ARRIVAL, the ATC clearance 

authorizes aircraft to descend at the pilots’ discretion, as 

long as the pilot crosses the PENNS Intersection at 6,000 

feet MSL. [Figure 3-17]

In the United States, Canada, and many other countries, 

the common altitude for changing to the standard 

altimeter setting of 29.92 inches of mercury ("Hg) (or 

1013.2 hectopascals or millibars) when climbing to the high 

altitude structure is 18,000 feet. When descending from 

high altitude, the altimeter should be changed to the local 

altimeter setting when passing through FL 180, although 

in most countries throughout the world the change to or 

from the standard altimeter setting is not done at the same 

altitude for each instance. 

For example, the flight level where aircrews change their 

altimeter setting to the local altimeter setting is specified 

by ATC each time they arrive at a specific airport. This 

information is shown on STAR charts outside the United 

States with the words: TRANS LEVEL: BY ATC. When 

departing from that same airport (also depicted typically on 

the STAR chart), the altimeter should be set to the standard 

setting when passing through 5,000 feet, as an example. 

This means that altimeter readings when flying above 

5,000 feet are actual flight levels, not feet. This is common 

for Europe, but very different for pilots experienced with 

flying in the United States and Canada.

Although standardization of these procedures for terminal 

locations is subject to local considerations, specific criteria 

apply in developing new or revised arrival procedures. 

Normally, high performance airplanes enter the terminal 

area at or above 10,000 feet above the airport elevation 

and begin their descent 30 to 40 NM from touchdown on 

the landing runway. Unless pilots indicate an operational 

need for a lower altitude, descent below 5,000 feet above 

the airport elevation is typically limited to an altitude where 

final descent and glideslope intercept can be made without 

exceeding specific obstacle clearance and other related 

arrival, approach, and landing criteria.

Arrival delays typically are absorbed at a metering fix. 

This fix is established on a route prior to the terminal 

airspace, 10,000 feet or more above the airport elevation. 

The metering fix facilitates profile descents, rather than 

controllers using delaying vectors or a holding pattern at 

low altitudes. Descent restrictions normally are applied 

prior to reaching the final approach phase to preclude 

relatively high descent rates close in to the destination 

airport. At least 10 NM from initial descent from 10,000 
3-19

Figure 3-16. Assigned altitudes.

0102 VON81 ot 0102 TCO12, 3- CE

EC-3, 21 OCT 2010 to 18 NOV 2010

NOT FOR NAVIGATION

"Aircraft 20350, descend via the JANESVILLE 

FIVE ARRIVAL."

Descent is at your discretion; however, you must 

adhere to the minimum crossing altitudes and 

airspeed restrictions printed on the chart.

"Aircraft 20350, cleared via the JANESVILLE

FIVE ARRIVAL."

The controller is only giving you a routing clearance

and will specify any altitudes and airspeeds to y.

feet above the airport elevation, the controller issues 

an advisory that details when to expect to commence 

the descent. ATC typically uses the phraseology, “Expect 

descent in (number) miles.” Standard ATC phraseology 

is, “Maintain (altitude) until specified point (e.g., abeam 

landing runway end), cleared for visual approach or expect 

visual or contact approach clearance in (number of miles, 

minutes, or specified point).”

Once the determination is made regarding the instrument 

approach and landing runway pilots use, ATC will not 

permit a change to another NAVAID that is not aligned with 

the landing runway. When altitude restrictions are required 

for separation purposes, ATC avoids assigning an altitude 

below 5,000 feet above the airport elevation.

There are numerous exceptions to the high performance 

airplane arrival procedures previously outlined. For 

example, in a non-radar environment, the controller may 

clear the flight to use an approach based on a NAVAID 

other than the one aligned with the landing runway, such 

as a circling approach. In this case, the descent to a lower 

altitude usually is limited to the circling approach area with 

the circle-to-land maneuver confined to the traffic pattern.

IFR en route descent procedures should include a review 
3-20

Figure 3-17. Altitude restrictions.

0102 VON81 ot 0102 TCO12, 2- EN

NE-2, 21 OCT 2010 to 18 NOV 2010

NOT FOR NAVIGATION If you are at RACKI Intersection at 12,000 feet 

MSL, you must adjust your rate of descent so 

you can reach 6,000 feet MSL in the distance 

available. At a groundspeed of 180 knots (3 

NM per minute), you will reach PENNS 

Intersection in approximately 8 minutes (23 ÷ 3

= 7.6). You must descend at least 750 feet per 

minute to cross PENNS at 6,000 feet MSL 

(6,000 ÷ 8 = 750).

You are at HAYED Intersection at 12,000 feet MSL. Your planned rate of descent is 500 feet per minute 

and your groundspeed is approximately 180 knots (3 NM per minute). You should begin your descent no 

less than 36 NM from PENNS Intersection ([6,000 ÷ 500] x 3 = 36).

 "Piper 6319K, cross PENNS Intersection at 6,000, maintain 6,000."

of minimum, maximum, mandatory, and recommended 

altitudes that normally precede the fix or NAVAID facility 

to which they apply. The initial descent gradient for a low 

altitude instrument approach procedure does not exceed 

500 FPNM (approximately 5°), and for a high altitude 

approach, the maximum allowable initial gradient is 1,000 

FPNM (approximately 10°). 

Remember during arrivals, when cleared for an instrument 

approach, maintain the last assigned altitude until 

established on a published segment of the approach or on 

a segment of a published route. If no altitude is assigned 

with the approach clearance and the aircraft is already on a 

published segment, the pilot can descend to its minimum 

altitude for that segment of the approach. 

Airspeed 

During the arrival, expect to make adjustments in speed at 

the controller’s request. When pilots fly a high-performance 

aircraft on an IFR flight plan, ATC may ask them to adjust 

their airspeed to achieve proper traffic sequencing 

and separation. This also reduces the amount of radar 

vectoring required in the terminal area. When operating 

a reciprocating engine or turboprop airplane within 20 

NM from the destination airport, 150 knots is usually the 

slowest airspeed that is assigned. If the aircraft cannot 

maintain the assigned airspeed, the pilot must advise ATC. 

Controllers may ask pilots to maintain the same speed as 

the aircraft ahead of or behind them on the approach. Pilots 

are expected to maintain the specified airspeed ±10 knots. 

At other times, ATC may ask pilots to increase or decrease 

airspeed by 10 knots, or multiples thereof. When the speed 

adjustment is no longer needed, ATC advises the pilot to “...

resume normal speed.”

Keep in mind that the maximum speeds specified in 14 CFR 

Part 91, section 91.117 still apply during speed adjustments. 

It is the pilot’s responsibility to advise ATC if an assigned 

speed adjustment would cause an exceedence of these 

limits. For operations in Class C or D airspace at or below 

2,500 feet above ground level (AGL), within 4 NM of the 

primary airport, ATC has the authority to approve a faster 

speed than those prescribed in 14 CFR Part 91, section 

91.117.

Pilots operating at or above 10,000 feet MSL on an assigned 
3-21

Figure 3-18. Instead of flying for a specific time after passing the holding fix, these holding patterns use distances to mark where the 

turns are made. The distances come from DME or IFR-certified GPS equipment.

SET

“...Viking 5786P, hold east of the 20 DME x on the 

265° radial of the stedman VORTAC, 5 mile legs...”

“...Bonanza 8394K, hold

northeast of the 16 DME x on

the 030° radial of the stedman 

VORTAC, 5 mile legs...”

speed adjustment that is greater than 250 KIAS are expected 

to reduce speed to 250 KIAS to comply with 14 CFR Part

91, section 91.117(a) when cleared below 10,000 feet MSL, 

within domestic airspace. This speed adjustment is made 

without notifying ATC. Pilots are expected to comply with 

the other provisions of 14 CFR Part 91, section 91.117 

without notifying ATC. For example, it is normal for faster 

aircraft to level off at 10,000 feet MSL while slowing to the 

250 KIAS limit that applies below that altitude, and to level 

off at 2,500 feet above airport elevation to slow to the 200 

KIAS limit that applies within the surface limits of Class C 

or D airspace. Controllers anticipate this action and plan 

accordingly.

Speed restrictions of 250 knots do not apply to aircraft 

operating beyond 12 NM from the coastline within the 

United States Flight Information Region in offshore Class 

E airspace below 10,000 feet MSL. In airspace underlying 

a Class B airspace area designated for an airport, pilots are 

expected to comply with the 200 KIAS limit specified in 14 

CFR Part 91, section 91.117(c). (See 14 CFR Part 91, sections 

91.117(c) and 91.703.) Approach clearances cancel any 

previously assigned speed adjustment.

Holding Patterns

If aircraft reach a clearance limit before receiving a further 

clearance from ATC, a holding pattern is required at the 

last assigned altitude. Controllers assign holds for a variety 

of reasons, including deteriorating weather or high traffic 

volume. Holding might also be required following a missed

approach. Since flying outside the area set aside for a 

holding pattern could lead to an encounter with terrain 

or other aircraft, aircrews need to understand the size of 

the protected airspace that a holding pattern provides.

Each holding pattern has a fix, a direction to hold from 

the fix, and an airway, bearing, course, radial, or route on 

which the aircraft is to hold. These elements, along with the 

direction of the turns, define the holding pattern.

Since the speed of the aircraft affects the size of a 

holding pattern, maximum holding airspeeds have been 

designated to limit the amount of airspace that must be 

protected. The three airspeed limits are shown in Figure 

2-73 in Chapter 2, En Route Operations, of this book. Some 

holding patterns have additional airspeed restrictions to 

keep faster airplanes from flying out of the protected area. 

These are depicted on charts by using an icon and the 

limiting airspeed.

DME and IFR-certified GPS equipment offer some additional 

options for holding. Rather than being based on time, the 

leg lengths for DME/GPS holding patterns are based on 

distances in nautical miles. These patterns use the same 

entry and holding procedures as conventional holding 

patterns. The controller or the instrument approach 

procedure chart specifies the length of the outbound leg. 

The end of the outbound leg is determined by the DME 

or the along track distance (ATD) readout. The holding 

fix on conventional procedures, or controller-defined 

holding based on a conventional navigation aid with DME, 

is a specified course or radial and distances are from the 

DME station for both the inbound and outbound ends of 

the holding pattern. When flying published GPS overlay 

or standalone procedures with distance specified, the 

holding fix is a waypoint in the database and the end of the 
3-22

Figure 3-19. Cleared present position direct from V295.

NOT FOR NAVIGATION

outbound leg is determined by the ATD. Instead of using 

the end of the outbound leg, some FMS are programmed 

to cue the inbound turn so that the inbound leg length 

matches the charted outbound leg length.

Normally, the difference is negligible, but in high winds, 

this can enlarge the size of the holding pattern. Aircrews 

need to understand their aircraft’s FMS holding program to 

ensure that the holding entry procedures and leg lengths 

match the holding pattern. Some situations may require 

pilot intervention in order to stay within protected airspace. 

[Figure 3-18]

Approach Clearance

The approach clearance provides guidance to a position 

from where the pilot can execute the approach. It is also 

a clearance to fly that approach. If only one approach 

procedure exists, or if ATC authorizes the aircrew to execute 

the approach procedure of their choice, the clearance 

may be worded as simply as “... cleared for approach.” 

If ATC wants to restrict the pilot to a specific approach, 

the controller names the approach in the clearance. For 

example, “...cleared ILS Runway 35 Right approach.”

When the landing is to be made on a runway that is not 

aligned with the approach being flown, the controller may 

issue a circling approach clearance, such as “...cleared 

for VOR Runway 17 approach, circle to land Runway 23.” 

Approaches whose final approach segment is more than 30 

degrees different from the landing runway alignment are 

always designated as circling approaches. Unless a specific 

landing runway is specified in the approach clearance, 

the pilot may land on any runway. Pilots landing at nontowered airports are reminded of the importance of making 

radio calls as set forth in the AIM. 

When cleared for an approach prior to reaching a holding 

fix, ATC expects the pilot to continue to the holding fix, 
3-23

Figure 3-20. Cleared for the Palm Beach ILS approach.

SE-3, 21 OCT 2010 to 18 NO

V 2010

SE-3, 21 OCT 2010 to 18 NO

V 2010

NOT FOR NAVIGATION

Direct from V295
3-24

Figure 3-21. Arrival instructions when established.

25

IAF IAF

2

1

3

LIMA

LOM

1500

6 DME

X-RAY

INT

1300

12 DME

4000

20 DME

ALPHA

INT

along the feeder route associated with the fix, and then 

to the IAF. If a feeder route to an IAF begins at a fix located 

along the route of flight prior to reaching the holding fix, 

and clearance for an approach is issued, the pilot should 

commence the approach via the published feeder route. 

The pilot is expected to commence the approach in a 

similar manner at the IAF, if the IAF is located along the 

route to the holding fix.

ATC also may clear an aircraft directly to the IAF by using 

language such as “direct” or “proceed direct.” Controllers 

normally identify an approach by its published name, 

even if some component of the approach aid (such as 

the glideslope of an ILS) is inoperative or unreliable. The 

controller uses the name of the approach as published but 

advises the aircraft when issuing the approach clearance 

that the component is unusable. 

Present Position Direct

In addition to using high and low altitude en route charts 

as resources for arrivals, area charts can be helpful as a 

planning aid for SA. Many pilots find the area chart helpful 

in locating a depicted fix after ATC clears them to proceed 

to a fix and hold, especially at unfamiliar airports.

Looking at Figures 3-19 and 3-20 assume the pilot is on 

V295 northbound en route to Palm Beach International 

Airport. The pilot is en route on the airway when the 

controller clears him present position direct to the ZISUR 

(IAF) and for the ILS approach. There is no transition 

authorized or charted between his present position and the 

approach facility. There is no minimum altitude published 

for the route the pilot is about to travel.

In Figure 3-20, the pilot is just north of HEATT Intersection 

at 5,000 feet when the approach controller states, “Citation

9724J, 2 miles from HEATT, cleared present position 

direct ZISUR, cleared for the Palm Beach ILS Runway 10L 

Approach, contact Palm Beach Tower on 119.1 established 

inbound.” With no minimum altitude published from that 

point to the ZISUR intersection, the pilot should maintain 

the last assigned altitude until he reaches the IAF. In 

Figure 3-19, after passing ZISUR intersection outbound, 

commence the descent to 2,000 feet for the course reversal.

The ILS procedure relies heavily on the controller’s 

recognition of the restriction upon the pilot to maintain 

the last assigned altitude until “established” on a published 

segment of the approach. Prior to issuing a clearance for the 

approach, the controller usually assigns the pilot an altitude 

to maintain until established on the final approach course ,

compatible with glideslope intercept.

Radar Vectors to Final Approach Course 

Arriving aircraft usually are vectored to intercept the final 

approach course, except with vectors for a visual approach, 

at least 2 NM outside the approach gate unless one of the 

following exists: 

1. When the reported ceiling is at least 500 feet above 

the minimum vectoring altitude or minimum IFR 

altitude and the visibility is at least 3 NM (report 

may be a pilot report if no weather is reported for 
3-25

Figure 3-22. Arrival instructions when not established.

4000

12 DME

ALPHA

IAF

FAF

Straight-in ILS

the airport), aircraft may be vectored to intercept 

the final approach course closer than 2 NM outside 

the approach gate but no closer than the approach 

gate. 

2. If specifically requested by a pilot, ATC may vector 

aircraft to intercept the final approach course inside 

the approach gate but no closer than the final 

approach fix (FAF).

For a precision approach, aircraft are vectored at an altitude 

that is not above the glideslope/glidepath or below the 

minimum glideslope intercept altitude specified on the 

approach procedure chart. For a non-precision approach, 

aircraft are vectored at an altitude that allows descent in 

accordance with the published procedure.

When a vector takes the aircraft across the final approach 

course, pilots are informed by ATC and the reason for the 

action is stated. In the event that ATC is not able to inform 

the aircraft, the pilot is not expected to turn inbound on 

the final approach course unless an approach clearance has 

been issued. An example of ATC phraseology in this case 

is, “... expect vectors across final for spacing.”

The following ATC arrival instructions are issued to an IFR

aircraft before it reaches the approach gate: 

1. Position relative to a fix on the final approach course. 

If none is portrayed on the controller’s radar display 

or if none is prescribed in the instrument approach 

procedure, ATC issues position information relative 

to the airport or relative to the NAVAID that provides 

final approach guidance. 

2. Vector to intercept the final approach course if 

required. 

3. Approach clearance except when conducting a radar 

approach. ATC issues the approach clearance only 

after the aircraft is established on a segment of a 

published route or instrument approach procedure, or 

in the following examples as depicted in Figure 3-21. 

Aircraft 1 was vectored to the final approach course 

but clearance was withheld. It is now at 4,000 feet and 

established on a segment of the instrument approach 

procedure. “Seven miles from X-RAY. Cleared ILS runway 

three six approach.”

Aircraft 2 is being vectored to a published segment of 

the final approach course, 4 NM from LIMA at 2,000 feet. 

The minimum vectoring altitude for this area is 2,000 feet. 

“Four miles from LIMA. Turn right heading three four zero. 

Maintain two thousand until established on the localizer. 

Cleared ILS runway three six approach.”

Aircraft 3: There are many times when it is desirable to 

position an aircraft onto the final approach course prior to 

a published, charted segment of an instrument approach 

procedure (IAP). 

Sometimes IAPs have no initial segment and require 

vectors. “RADAR REQUIRED” is charted in the plan view. 

Sometimes a route intersects an extended final approach 

course making a long intercept desirable.

When ATC issues a vector or clearance to the final approach 

course beyond the published segment, controllers assign 

an altitude to maintain until the aircraft is established on 

a segment of a published route or IAP. This ensures that 

both the pilot and controller know precisely what altitude 

is to be flown and precisely where descent to appropriate 

minimum altitudes or step-down altitudes can begin.

Most aircraft are vectored onto a localizer or final approach 

course between an intermediate fix and the approach gate. 
3-26

Figure 3-27. Special airports and comments.

Special Airports

Kodiak, AK

Petersburg, AK

Cape Newenham AFS, AK

Washington, DC (National)

Shenandoah Valley, VA

(Stanton-Waynesboro-Harrisonburg)

Aspen, CO

Gunnison, CO

Missoula, MT

Jackson Hole, WY

Hailey, ID (Friedman Memorial)

Hayden, Yampa Valley, CO

Lihue, Kauai, HI

Ontario, CA

Comments

Airport is surrounded by mountainous terrain. Any go-around beyond ILS or GCA 

MAP will not provide obstruction clearance.

Mountainous terrain in immediate vicinity of airport, all quadrants.

Runway located on mountain slope with high gradient factor; nonstandard 

instrument approach.

Special arrival/departure procedures.

Mountainous terrain.

High terrain; special procedures.

VOR only; uncontrolled; numerous obstructions in airport area; complete departure 

procedures.

Mountainous terrain; special procedures.

Mountainous terrain; all quadrants; complex departure procedures.

Mountainous terrain; special arrival/departure procedures.

Mountainous terrain; no control tower; special engine-out procedures for certain 

large airplanes.

High terrain; mountainous to 2,300 feet within 3 miles of the localizer.

Mountainous terrain and extremely limited visibility in haze conditions.

These aircraft normally are told to maintain an altitude until 

established on a segment of the approach.

When an aircraft is assigned a route that is not a published 

segment of an approach, the controller must issue an 

altitude to maintain until the aircraft is established on a 

published segment of the approach. [Figure 3-21] Assume 

the aircraft is established on the final approach course 

beyond the approach segments, 8 NM from Alpha at 6,000 

feet. The minimum vectoring altitude for this area is 4,000 

feet. “Eight miles from Alpha. Cross Alpha at or above four 

thousand. Cleared ILS runway three six approach.” 

If an aircraft is not established on a segment of a published 

approach and is not conducting a radar approach, 

ATC assigns an altitude to maintain until the aircraft 

is established on a segment of a published route or 

instrument approach procedure. [Figure 3-22]

The aircraft is being vectored to a published segment of the 

ILS final approach course, 3 NM from Alpha at 4,000 feet. 

The minimum vectoring altitude for this area is 4,000 feet. 

“Three miles from Alpha. Turn left heading two one zero. 

Maintain four thousand until established on the localizer. 

Cleared ILS runway one eight approach.”

The ATC assigned altitude ensures IFR obstruction 

clearance from the point at which the approach clearance 

is issued until established on a segment of a published 

route or instrument approach procedure.

ATC tries to make frequency changes prior to passing the 

FAF, although when radar is used to establish the FAF, ATC 

informs the pilot to contact the tower on the local control 

frequency after being advised that the aircraft is over the 

fix. For example, “Three miles from final approach fix. Turn 

left heading zero one zero. Maintain two thousand until 

established on the localizer. Cleared ILS runway three six 

approach. I will advise when over the fix.”

“Over final approach fix. Contact tower one-one eight 

point one.”

Special Airport Qualification

It is important to note an example of additional resources 

that are helpful for arrivals, especially into unfamiliar 

airports requiring special pilot or navigation qualifications. 

The operating rules governing domestic and flag air 

carriers require pilots in command to be qualified over 

the routes and into airports where scheduled operations 

are conducted, including areas, routes, and airports in 

which special pilot qualifications or special navigation 

qualifications are needed. For Part 119 certificate holders 

who conduct operations under 14 CFR Part 121, section 

121.443, there are provisions in OpSpecs under which 

operators can comply with this regulation. Figure 3-27 

provides some examples of special airports in the United 

States along with associated comments.
4-1

Introduction

This chapter discusses general planning and conduct of 

instrument approaches by pilots operating under Title 14 

of the Code of Federal Regulations (14 CFR) Parts 91,

121, 125, and 135. The operations specifications (OpSpecs), 

standard operating procedures (SOPs), and any other 

Federal Aviation Administration (FAA) approved documents 

for each commercial operator are the final authorities for 

individual authorizations and limitations as they relate 

to instrument approaches. While coverage of the various 

authorizations and approach limitations for all operators 

is beyond the scope of this chapter, an attempt is made 

to give examples from generic manuals where it is 

appropriate.

Approaches

Chapter 4
4-2

Approach Planning 

Depending on speed of the aircraft, availability of weather 

information, and the complexity of the approach procedure 

or special terrain avoidance procedures for the airport 

of intended landing, the in-flight planning phase of an 

instrument approach can begin as far as 100-200 nautical 

miles (NM) from the destination. Some of the approach 

planning should be accomplished during preflight. In 

general, there are five steps that most operators incorporate 

into their flight standards manuals for the in-flight planning 

phase of an instrument approach: 

• 	 Gathering weather information, field conditions,

and Notices to Airmen (NOTAMs) for the airport of 

intended landing. 

• 	 Calculation of performance data, approach speeds,

and thrust/power settings. 

• 	 Flight deck navigation/communication and

automation setup.

• 	 Instrument approachprocedure (IAP)reviewand,for

flight crews, IAP briefing. 

• 	 Operationalreview and, for flight crews, operational

briefing. 

Although often modified to suit each individual operator, 

these five steps form the basic framework for the in-flight 

planning phase of an instrument approach. The extent of 

detail that a given operator includes in their SOPs varies 

from one operator to another; some may designate which 

pilot performs each of the above actions, the sequence, and 

the manner in which each action is performed. Others may 

leave much of the detail up to individual flight crews and 

only designate which tasks should be performed prior to 

commencing an approach. Flight crews of all levels, from 

single-pilot to multi-crewmember Part 91 operators, can 

benefit from the experience of commercial operators in 

developing techniques to fly standard instrument approach 

procedures (SIAPs).

Determining the suitability of a specific IAP can be a very 

complex task, since there are many factors that can limit 

the usability of a particular approach. There are several 

questions that pilots need to answer during preflight 

planning and prior to commencing an approach. Is the 

approach procedure authorized for the company, if Part 

91, subpart K, 121, 125, or 135? Is the weather appropriate 

for the approach? Is the aircraft currently at a weight that 

will allow it the necessary performance for the approach 

and landing or go around/ missed approach? Is the aircraft 

properly equipped for the approach? Is the flight crew 

qualified and current for the approach? Many of these types 

of issues must be considered during preflight planning and 

within the framework of each specific air carrier’s OpSpecs, 

or Part 91. 

Weather Considerations 

Weather conditions at the field of intended landing dictate 

whether flight crews need to plan for an instrument 

approach and, in many cases, determine which approaches 

can be used, or if an approach can even be attempted. The 

gathering of weather information should be one of the first 

steps taken during the approach-planning phase. Although 

there are many possible types of weather information, 

the primary concerns for approach decision-making are 

windspeed, wind direction, ceiling, visibility, altimeter 

setting, temperature, and field conditions. It is also a good 

idea to check NOTAMs at this time, in case there were any 

changes since preflight planning.

Windspeed and direction are factors because they often 

limit the type of approach that can be flown at a specific 

location. This typically is not a factor at airports with 

multiple precision approaches, but at airports with only a 

few or one approach procedure, the wrong combination of 

wind and visibility can make all instrument approaches at 

an airport unavailable. Pilots must be prepared to execute 

other available approaches, not just the one that they may 

have planned for. As an example, consider the available 

approaches at the Chippewa Valley Regional Airport (KEAU) 

in Eau Claire, Wisconsin. [Figure 4-1] In the event that the 

visibility is reported as less than one mile, the only useable 

approaches for Category C airplanes is the Instrument 

Landing System (ILS) and Lateral navigation (LNAV)/vertical 

navigation (VNAV) to Runway 22. This leaves very few 

options for flight crews if the wind does not favor Runway 

22; and, in cases where the wind restricts a landing on that 

runway altogether, even a circling approach cannot be 

flown because of the visibility. 

Weather Sources

Most of the weather information that flight crews receive 

is issued to them prior to the start of each flight segment, 

but the weather used for in-flight planning and execution 

of an instrument approach is normally obtained en route 

via government sources, company frequency, or Aircraft 

Communications Addressing and Reporting System 

(ACARS).

Air carriers and operators certificated under the provisions 

of Part 119 (Certification: Air Carriers and Commercial 

Operators) are required to use the aeronautical weather 

information systems defined in the OpSpecs issued to that 

certificate holder by the FAA. These systems may use basic 

FAA/National Weather Service (NWS) weather services, 

contractor or operator-proprietary weather services, and/ 
4-3

Figure 4-1. Chippewa Regional Airport (KEAU), Eau Claire, Wisconsin.

EC-3, 18 NO

V 2010 to 16 DEC 2010

EC-3, 18 NO

V 2010 to 16 DEC 2010

EC-3, 18 NOV 2010 ot 16 DEC 2010

EC-3, 18 NOV 2010 to 16 DEC 2010

EC-3, 18 NOV 2010 to 16 DEC 2010

EC-3, 18 NOV 2010 to 16 DEC 2010

16 DEC 2010

EC-3, 18 NOV

NOT FOR NAVIGATION
4-4

or Enhanced Weather Information System (EWINS) when 

approved in the OpSpecs. As an integral part of EWINS 

approval, the procedures for collecting, producing, and 

disseminating aeronautical weather information, as well 

as the crewmember and dispatcher training to support 

the use of system weather products, must be accepted or 

approved.

Operators not certificated under the provisions of 14 

CFR Part 119 are encouraged to use FAA/NWS products 

through Flight Service Station (FSS)/Automated Flight 

Service Station (AFSS). FSS and AFSS provide pilot weather 

briefings, en route weather, receive and process instrument 

flight rule (IFR) and visual flight rule (VFR) flight plans, 

relay air traffic control (ATC) clearances, and issue NOTAMs. 

They also provide assistance to lost aircraft and aircraft in 

emergency situations and conduct VFR search and rescue 

services.

Direct User Access Terminal System (DUATS), funded by 

the FAA, allows any pilot with a current medical certificate 

to access weather information and file a flight plan via 

computer. Two methods of access are available to connect 

with DUATS. The first is on the internet at www.duats.com

or www.duat.com. The second method requires a modem 

and a communications program supplied by a DUATS 

provider. To access the weather information and file a 

flight plan by this method, pilots use a toll free telephone 

number to connect the user’s computer directly to the 

DUATS computer. The current vendors of DUATS service 

and the associated phone numbers are listed in Chapter 7 

of the Aeronautical Information Manual (AIM).

Flight Information Service—Broadcast (FIS-B) provides 

certain aviation weather and other aeronautical information 

to aircraft equipped with an appropriate flight deck display. 

Reception of FIS-B services can be expected within a 

ground station coverage volume when line-of-sight 

geometry is maintained between the aircraft and ground 

station. National Airspace System (NAS) wide service 

availability was targeted for 2013 and is currently available 

within certain regions. FIS-B provides the following textual 

and graphical aviation weather and aeronautical products 

free-of-charge. A detailed description of these products 

can be found in the AIM.

•	 Aviation Digital Data Services (ADDS) provides the 

aviation community with text, digital and graphical 

forecasts, analyses, and observations of aviation 

related weather variables. ADDS is a joint effort of 

National Oceanic and Atmospheric Administration’s 

(NOAA) Earth System Research Laboratory, National 

Center for Atmospheric Research (NCAR) Research 

Applications Laboratory (RAL), and the Aviation 

Weather Center (AWC).

•	 Hazardous In-flight Weather Advisory Service 

(HIWAS) is a national program for broadcasting 

hazardous weather information continuously over 

selected navigation aids (NAVAIDs). The broadcasts 

include advisories such as Airman’s Meteorological 

Information (AIRMETs), Significant Meteorological 

Information (SIGMETs), convective SIGMETs, and 

urgent pilot weather reports (PIREPs/UUA). These 

broadcasts are only a summary of the information, 

and pilots should contact an FSS/AFSS or En 

Route Flight Advisory Service (EFAS) for detailed 

information.

•	 Telephone Information Briefing Service (TIBS) is 

a service prepared and disseminated by selected 

AFSS. It provides continuous telephone recordings 

of meteorological and aeronautical information. 

Specifically, TIBS provides area and route briefings, 

as well as airspace procedures and special 

announcements, if applicable. It is designed to be 

a preliminary briefing tool and is not intended to 

replace a standard briefing from a flight service 

specialist. The TIBS service is available 24 hours a day 

and is updated when conditions change, but it can 

only be accessed by a touch tone phone. The phone 

numbers for the TIBS service are listed in the Airport/

Facility Directory (A/FD). TIBS should also contain, 

but is not limited to: surface observations, terminal 

aerodrome forecast (TAFs), and winds/temperatures 

aloft forecasts.

The suite of available aviation weather product types 

is expanding with the development of new sensor 

systems, algorithms, and forecast models. The FAA and 

NWS, supported by the NCAR and the FSL, develop and 

implement new aviation weather product types through 

a comprehensive process known as the Aviation Weather 

Technology Transfer process. This process ensures that 

user needs and technical and operational readiness 

requirements are met as experimental product types 

mature to operational application.

The development of enhanced communications 

capabilities, most notably the internet, has allowed pilots 

access to an increasing range of weather service providers 

and proprietary products. It is not the intent of the FAA to 

limit operator use of this weather information. However, 

pilots and operators should be aware that weather services 

provided by entities other than the FAA, NWS, or their 

contractors (such as the DUATS and flight information 

services data link (FISDL) providers) may not meet FAA/
4-5

NWS quality control standards.

Broadcast Weather 

The most common method used by flight crews to obtain 

specific in-flight weather information is to use a source that 

broadcasts weather for the specific airport. Information 

about ceilings, visibility, wind, temperature, barometric 

pressure, and field conditions can be obtained from most 

types of broadcast weather services. Broadcast weather 

can be transmitted to the aircraft in radio voice format or 

digital format, if it is available, via an ACARS system. 

Automated Terminal Information Service (ATIS)

Automatic terminal information service (ATIS) is the 

continuous broadcast of recorded non-control information 

in selected high activity terminal areas. Its purpose is to 

improve controller effectiveness and to relieve frequency 

congestion by automating the repetitive transmission 

of essential but routine information. The information is 

continuously broadcast over a discrete very high frequency 

(VHF) radio frequency or the voice portion of a local NAVAID. 

ATIS transmissions on a discrete VHF radio frequency are 

engineered to be receivable to a maximum of 60 NM from 

the ATIS site and a maximum altitude of 25,000 feet above 

ground level (AGL). At most locations, ATIS signals may be 

received on the surface of the airport, but local conditions 

may limit the maximum ATIS reception distance and/or 

altitude. Pilots are urged to cooperate in the ATIS program 

as it relieves frequency congestion on approach control, 

ground control, and local control frequencies. The A/FD 

indicates airports for which ATIS is provided.

ATIS information includes the time of the latest weather 

sequence, ceiling, visibility, obstructions to visibility, 

temperature, dew point (if available), wind direction 

(magnetic), velocity, altimeter, other pertinent remarks, 

instrument approach and runway in use. The ceiling/sky 

condition, visibility, and obstructions to vision may be 

omitted from the ATIS broadcast if the ceiling is above

5,000 feet and the visibility is more than five miles. The 

departure runway will only be given if different from the 

landing runway except at locations having a separate ATIS 

for departure. The broadcast may include the appropriate 

frequency and instructions for VFR arrivals to make initial 

contact with approach control. Pilots of aircraft arriving or 

departing the terminal area can receive the continuous 

ATIS broadcast at times when flight deck duties are least 

pressing and listen to as many repeats as desired. ATIS 

broadcast will be updated upon the receipt of any official 

hourly and special weather. A new recording will also be 

made when there is a change in other pertinent data, such 

as runway change and instrument approach in use.

Automated Weather Observing Programs

Automated weather reporting systems are increasingly 

being installed at airports. These systems consist of 

various sensors, a processor, a computer-generated voice 

subsystem, and a transmitter to broadcast local, minuteby-minute weather data directly to the pilot.

Automated Weather Observing System

The automated weather observing system (AWOS) 

observations include the prefix “AUTO” to indicate that 

the data are derived from an automated system. Some 

AWOS locations are augmented by certified observers who 

provide weather and obstruction to vision information 

in the remarks of the report when the reported visibility 

is less than 7 miles. These sites, along with the hours of 

augmentation, are published in the A/FD. Augmentation 

is identified in the observation as “OBSERVER WEATHER.” 

The AWOS wind speed, direction and gusts, temperature, 

dew point, and altimeter setting are exactly the same as 

for manual observations. The AWOS also reports density 

altitude when it exceeds the field elevation by more than 

1,000 feet. The reported visibility is derived from a sensor 

near the touchdown of the primary instrument runway. 

The visibility sensor output is converted to a visibility value 

using a 10-minute harmonic average. The reported sky 

condition/ ceiling is derived from the ceilometer located 

next to the visibility sensor. The AWOS algorithm integrates 

the last 30 minutes of ceilometer data to derive cloud layers 

and heights. This output may also differ from the observer 

sky condition in that the AWOS is totally dependent upon 

the cloud advection over the sensor site.

Automated Surface Observing System (ASOS)/

Automated Weather Sensor System (AWSS) 

The automated surface observing system (ASOS)/

automated weather sensor system (AWSS) is the primary 

surface weather observing system of the United States. The 

program to install and operate these systems throughout 

the United States is a joint effort of the NWS, the FAA, and 

the Department of Defense (DOD). AWSS is a follow-on 

program that provides identical data as ASOS. ASOS/AWSS 

is designed to support aviation operations and weather 

forecast activities. The ASOS/ AWSS provides continuous 

minute-by-minute observations and performs the basic 

observing functions necessary to generate a aviation 

routine weather report (METAR) and other aviation weather 

information. The information may be transmitted over a 

discrete VHF radio frequency or the voice portion of a local 

NAVAID. ASOS/AWSS transmissions on a discrete VHF radio 

frequency are engineered to be receivable to a maximum of 

25 NM from the ASOS/AWSS site and a maximum altitude 

of 10,000 feet AGL.
4-6

At many locations, ASOS/AWSS signals may be received 

on the surface of the airport, but local conditions may 

limit the maximum reception distance and/or altitude. 

While the automated system and the human may differ 

in their methods of data collection and interpretation, 

both produce an observation quite similar in form and 

content. For the objective elements, such as pressure, 

ambient temperature, dew point temperature, wind, and 

precipitation accumulation, both the automated system 

and the observer use a fixed location and time-averaging 

technique. The quantitative differences between the 

observer and the automated observation of these elements 

are negligible. For the subjective elements, however, 

observers use a fixed time (spatial averaging technique) to 

describe the visual elements (sky condition, visibility, and 

present weather, etc.), while the automated systems use 

a fixed location and time averaging technique. Although 

this is a fundamental change, the manual and automated 

techniques yield remarkably similar results within the limits 

of their respective capabilities.

The use of the aforementioned visibility reports and 

weather services are not limited for Part 91 operators. 

Part 121 and 135 operators are bound by their individual 

OpSpecs documents and are required to use weather 

reports that come from the NWS or other approved 

sources. While all OpSpecs are individually tailored, most 

operators are required to use ATIS information, runway 

visual range (RVR) reports, and selected reports from 

automated weather stations. All reports coming from an 

AWOS-3 station are usable for Part 121 and 135 operators. 

Each type of automated station has different levels of 

approval as outlined in individual OpSpecs. Ceiling and 

visibility reports given by the tower with the departure 

information are always considered official weather, and 

RVR reports are typically the controlling visibility reference. 

Refer to Chapter 1, Departures, of this manual, as well as 

the AIM section 7-1-12 for further description of automated 

weather systems.

Center Weather Advisories (CWA)

Center weather advisories (CWAs) are unscheduled inflight, 

flow control, air traffic, and aircrew advisories. By nature of 

its short lead time, the CWA is not a flight planning product. 

It is generally a nowcast for conditions beginning in the 

next 2 hours. CWAs will be issued:

1. As a supplement to an existing SIGMET, convective 

SIGMET, or AIRMET.

2. When an in-flight advisory has not been issued 

but observed or expected weather conditions 

meet SIGMET/AIRMET criteria based on current 

pilot reports and reinforced by other sources 

of information about existing meteorological 

conditions.

3. When observed or developing weather conditions 

do not meet SIGMET, convective SIGMET, or 

AIRMET criteria (e.g., in terms of intensity or area 

coverage), but current pilot reports or other 

weather information sources indicate that existing 

or anticipated meteorological phenomena will 

adversely affect the safe and efficient flow of air 

traffic within the ARTCC area of responsibility.

Weather Regulatory Requirements 

There are many practical reasons for reviewing weather 

information prior to initiating an instrument approach. 

Pilots must familiarize themselves with the condition of 

individual airports and runways so that they may make 

informed decisions regarding fuel management, diversions, 

and alternate planning. Because this information is critical, 

14 CFR requires pilots to comply with specific weather 

minimums for planning and execution of instrument flights 

and approaches.. 

Weather Requirements and Part 91 Operators

According to 14 CFR Part 91, section 91.103, the pilot in 

command (PIC) must become familiar with all available 

information concerning a flight prior to departure. 

Included in this directive is the fundamental basis for 

pilots to review NOTAMs and pertinent weather reports 

and forecasts for the intended route of flight. This review 

should include current weather reports and terminal 

forecasts for all intended points of landing and alternate 

airports. In addition, a thorough review of an airport’s 

current weather conditions should always be conducted 

prior to initiating an instrument approach. Pilots should 

also consider weather information as a planning tool for 

fuel management.

For flight planning purposes, weather information must be 

reviewed in order to determine the necessity and suitability 

of alternate airports. For Part 91 operations, the 600-2 and

800-2 rule applies to airports with precision and nonprecision approaches, respectively. Approaches with 

vertical guidance (APV) are non-precision approaches 

because they do not meet the International Civil Aviation 

Organization (ICAO) Annex 10 standards for a precision 

approach. (See Final Approach Segment section later in this 

chapter for more information regarding APV approaches.) 

Exceptions to the 600-2 and 800-2 alternate minimums are 

listed in the front of the National Aeronautical Navigational 

Products (AeroNav Products) in the Terminal Procedures 

Publication (TPP) and are indicated by a symbol on the 

approach charts for the airport. This does not preclude 

flight crews from initiating instrument approaches at 

A
4-7

alternate airports when the weather conditions are 

below these minimums. The 600-2 and 800-2 rules, or any 

exceptions, only apply to flight planning purposes, while 

published landing minimums apply to the actual approach 

at the alternate.

Weather Requirements and Part 135 Operators

Unlike Part 91 operators, Part 135 operators may not depart 

for a destination unless the forecast weather there will allow 

an instrument approach and landing. According to 14 CFR 

Part 135, section 135.219, flight crews and dispatchers 

may only designate an airport as a destination if the latest 

weather reports or forecasts, or any combination of them, 

indicate that the weather conditions will be at or above 

IFR landing minimums at the estimated time of arrival 

(ETA). This ensures that Part 135 flight crews consider 

weather forecasts when determining the suitability of 

destinations. Departures for airports can be made when the 

forecast weather shows the airport will be at or above IFR 

minimums at the ETA, even if current conditions indicate 

the airport to be below minimums. Conversely, 14 CFR 

Part 135, section 135.219 prevents departures when the 

first airport of intended landing is currently above IFR 

landing minimums, but the forecast weather is below those 

minimums at the ETA.

Another very important difference between Part 91 and 

Part 135 operations is the Part 135 requirement for airports 

of intended landing to meet specific weather criteria once 

the flight has been initiated. For Part 135, not only is the 

weather required to be forecast at or above instrument flight 

rules (IFR) landing minimums for planning a departure, 

but it also must be above minimums for initiation of an 

instrument approach and, once the approach is initiated, to 

begin the final approach segment of an approach. 14 CFR 

Part 135, section 135.225 states that pilots may not begin 

an instrument approach unless the latest weather report 

indicates that the weather conditions are at or above the 

authorized IFR landing minimums for that procedure. 14 

CFR Part 135, section 135.225 provides relief from this rule 

if the aircraft has already passed the final approach fix (FAF) 

when the weather report is received. It should be noted that 

the controlling factor for determining whether or not the 

aircraft can proceed is reported visibility. RVR, if available, 

is the controlling visibility report for determining that the 

requirements of this section are met. The runway visibility 

value (RVV), reported in statute miles (SM), takes precedent 

over prevailing visibility. There is no required timeframe for 

receiving current weather prior to initiating the approach.

Weather Requirements and Part 121 Operators

Like Part 135 operators, flight crews and dispatchers 

operating under Part 121 must ensure that the appropriate 

weather reports or forecasts, or any combination 

thereof, indicate that the weather will be at or above the 

authorized minimums at the ETA at the airport to which 

the flight is dispatched (14 CFR Part 121, section 121.613). 

This regulation attempts to ensure that flight crews will 

always be able to execute an instrument approach at 

the destination airport. Of course, weather forecasts are 

occasionally inaccurate; therefore, a thorough review 

of current weather is required prior to conducting an 

approach. Like Part 135 operators, Part 121 operators are 

restricted from proceeding past the FAF of an instrument 

approach unless the appropriate IFR landing minimums 

exist for the procedure. In addition, descent below the 

minimum descent altitude (MDA), decision altitude (DA), 

or decision height (DH) is governed, with one exception, 

by the same rules that apply to Part 91 operators. The 

exception is that during Part 121 and 135 operations, the 

airplane is also required to land within the touchdown 

zone (TDZ). Refer to the section titled Minimum Descent 

Altitude, Decision Altitude, and Decision Height later in this 

chapter for more information regarding MDA, DA, and DH. 

Aircraft Performance Considerations

All operators are required to comply with specific airplane 

performance limitations that govern approach and landing. 

Many of these requirements must be considered prior to the 

origination of flight. The primary goal of these performance 

considerations is to ensure that the aircraft can remain clear 

of obstructions throughout the approach, landing, and goaround phase of flight, as well as land within the distance 

required by the FAA. Although the majority of in-depth 

performance planning for an instrument flight is normally 

done prior to the aircraft’s departure, a general review of 

performance considerations is usually conducted prior to 

commencing an instrument approach. 

Airplane Performance Operating Limitations 

Generally speaking, air carriers must have in place an 

approved method of complying with Subpart I of 14 

CFR Parts 121 and 135 (Airplane Performance Operating 

Limitations), thereby proving the airplane’s performance 

capability for every flight that it intends to make. Flight 

crews must have an approved method of complying 

with the approach and landing performance criteria in 

the applicable regulations prior to departing for their 

intended destination. The primary source of information for 

performance calculations for all operators, including Part 

91, is the approved Aircraft Flight Manual (AFM) or Pilot’s 

Operating Handbook (POH) for the make and model of 

aircraft that is being operated. It is required to contain the 

manufacturer determined performance capabilities of the 

aircraft at each weight, altitude, and ambient temperature 

that are within the airplane’s listed limitations. Typically, the 

AFM for a large turbine powered airplane should contain 
4-8

information that allows flight crews to determine that 

the airplane will be capable of performing the following 

actions, considering the airplane’s landing weight and 

other pertinent environmental factor: 

•	 Landwithinthedistance requiredby the regulations.

•	 Climb from the missed approach point (MAP) and

maintain a specified climb gradient with one engine 

inoperative. 

•	 Perform a go-around from the finalstage of landing

and maintain a specified climb gradient with all 

engines operating and the airplane in the landing 

configuration. 

Many airplanes have more than one allowable flap 

configuration for normal landing. Often, a reduced flap 

setting for landing allows the airplane to operate at a higher 

landing weight into a field that has restrictive obstacles in 

the missed approach or rejected landing climb path. On 

these occasions, the full-flap landing speed may not allow 

the airplane enough energy to successfully complete a goaround and avoid any high terrain that might exist on the 

climb out. Therefore, all- engine and engine-out missed 

approaches, as well as rejected landings, must be taken 

into consideration in compliance with the regulations.

Aircraft Approach Categories

Aircraft approach category means a grouping of aircraft 

based on a reference landing speed (VREF), if specified, or 

if VREF is not specified, 1.3 VSO at the maximum certified 

landing weight. VREF, VSO, and the maximum certified 

landing weight are those values as established for the 

aircraft by the certification authority of the country of 

registry. A pilot must use the minima corresponding to 

the category determined during certification or higher. 

Helicopters may use Category A minima. If it is necessary 

to operate at a speed in excess of the upper limit of the 

speed range for an aircraft’s category, the minimums 

for the higher category must be used. For example, an 

airplane that fits into Category B, but is circling to land at 

a speed of 145 knots, must use the approach Category D 

minimums. As an additional example, a Category A airplane 

(or helicopter) that is operating at 130 knots on a straight-in 

approach must use the approach Category C minimums. 

See the following category limits noting that the airspeeds 

depicted are indicated airspeeds (IAS):

•	 Category A: Speed less than 91 knots.

•	 CategoryB: Speed91 knotsormorebutlessthan121

knots. 

•	 Category C: Speed 121 knots or more but less than

141 knots. 

•	 Category D: Speed 141 knots or more but less than

166 knots. 

•	 Category E: Speed 166 knots or more.

NOTE: Helicopter pilots may use the Category A line of 

minimums provided the helicopter is operated at Category 

A airspeeds. 

An airplane is certified in only one approach category, and 

although a faster approach may require higher category 

minimums to be used, an airplane cannot be flown to the 

minimums of a slower approach category. The certified 

approach category is permanent and independent of 

the changing conditions of day-to-day operations. From 

a terminal instrument procedures (TERPS) viewpoint, 

the importance of a pilot not operating an airplane at 

a category line of minimums lower than the airplane is 

certified for is primarily the margin of protection provided 

for containment of the airplane within the procedure 

design for a slower airplane. This includes height loss at 

the decision altitude, missed approach climb surface, and 

turn containment in the missed approach at the higher 

category speeds.

Pilots are responsible for determining if a higher approach 

category applies. If a faster approach speed is used that 

places the aircraft in a higher approach category, the 

minimums for the appropriate higher category must be 

used. Emergency returns at weights in excess of maximum 

certificated landing weight, approaches made with 

inoperative flaps, and approaches made in icing conditions 

for some airplanes are examples of situations that can 

necessitate the use of higher approach category minima.

Circling approaches are one of the most challenging 

flight maneuvers conducted in the NAS, especially for 

pilots of CAT C and CAT D turbine-powered, transport 

category airplanes These maneuvers are conducted at 

low altitude, day and night, and often with precipitation 

present affecting visibility, depth perception, and the ability 

to adequately assess the descent profile to the landing 

runway. Most often, circling approaches are conducted to 

runways without the benefit of electronic navigation aids to 

support the descent from the Circling Minimums Decision 

Altitude (CMDA) to the runway.

Circling approaches conducted at faster-than-normal, 

straight-in approach speeds also require a pilot to 

consider the larger circling approach area, since published 

circling minimums provide obstacle clearance only 

within the appropriate area of protection and is based 

on the approach category speed. [Figure 4-2] The circling 

approach area is the obstacle clearance area for airplanes 

maneuvering to land on a runway that does not meet the 
4-9

Figure 4-2. Construction of circling approach area.

A

B

C

D

E

1.3

1.5

1.7

2.3

4.5

Approach category Radius (miles)

RADII (r) defining size of areas, vary 

with the approach category

Circling

approach area

r

r

r

r

r

criteria for a straight- in approach. The size of the circling 

area varies with the approach category of the airplane, as 

shown in Figure 4-2.

A minimum of 300 feet of obstacle clearance is provided 

in the circling segment. Pilots should remain at or above 

the circling altitude until the airplane is continuously in a 

position from which a descent to a landing on the intended 

runway can be made at a normal rate of descent and using 

normal maneuvers. Since an approach category can make 

a difference in the approach and weather minimums and, 

in some cases, prohibit flight crews from initiating an 

approach, the approach speed should be calculated and 

the effects on the approach determined and briefed in 

the preflight planning phase, as well as reviewed prior to 

commencing an approach.

Prior to TERPS Change 21, pilots were often faced with 

the challenge of descending using a stabilized approach 

concept if the CMDA height above airport (HAA) exceeded 

1,200 feet. Once the HAA approached 1,200 feet, pilots were 

often forced to increase their rates of descent in order to 

arrive at the appropriate “in-slot” position. “In-slot” being 

defined as at a minimum, a CAT C or CAT D turbine-powered 

airplane should be wings level on a 3 degree - 318’/NM 

descent path not less than 1 NM from the touchdown 

point (1,000 feet beyond runway threshold). This was due 

to the small size of the circling protected airspace that the 

aircrews must remain within to ensure obstacle clearance.

The TERPS Change 21 to the circling protected airspace 

afforded much greater obstacle protection. However, it 

also afforded the pilot the opportunity to use the extra 

protected airspace to mitigate the need to conduct a 

high descent rate, unstabilized approach that was often 

necessary as a result of the previous criteria for the Circling 

Approach Radius (CAR). For example, under TERPS Change 

21, a sea level airport with a 1,500 ft HAA will have CAT C 

CAR of 2.86 NM, a 1.16 NM (68.5%) increase over pre-TERPS 

Change 21 CAR for CAT C. This extra protected airspace 

can be used by the pilot to maneuver the airplane instead 

of being forced to use high descent rates which are often 

necessary for high HAA circling approaches.

Most commercial operators dictate standard procedures for 

conducting instrument approaches in their FAA-approved 

manuals. These standards designate company callouts, 

flight profiles, configurations, and other specific duties 

for each flight deck crewmember during the conduct of 

an instrument approach.

Instrument Approach Charts

Beginning in February 2000, the FAA began issuing the 

current format for instrument approach plates (IAPs). This 

chart was developed by the Department of Transportation 

(DOT), Volpe National Transportation Systems Center and 

is commonly referred to as the Pilot Briefing Information

format. The FAA chart format is presented in a logical order,

facilitating pilot briefing of the procedures. [Figure 4-3]

Approach Chart Naming Conventions 

Individual FAA charts are identified on both the top and 

bottom of the page by their procedure name (based on the 

NAVAIDs required for the final approach), runway served, 

and airport location. The identifier for the airport is also 

listed immediately after the airport name. [Figure 4-4]

There are several types of approach procedures that may 

cause some confusion for flight crews unfamiliar with the 

naming conventions. Although specific information about 

each type of approach is covered later in this chapter, listed 

below are a few procedure names that can cause confusion.

Straight-In Procedures

When two or more straight-in approaches with the same 

type of guidance exist for a runway, a letter suffix is added 

to the title of the approach so that it can be more easily 

identified. These approach charts start with the letter Z 

and continue in reverse alphabetical order. For example, 

consider the (RNAV) (GPS) Z RWY 13C and RNAV (RNP) Y 

RWY 13C approaches at Chicago Midway International 

Airport. [Figure 4-5] Although these two approaches can 
4-10

Figure 4-3. Instrument approach chart.

NE-1, 10 MAR 2011 to 07 APR 2011

NE-1, 10 MAR 2011 to 07 APR 2011

NOT FOR NAVIGATION PLAN VIEW PROFILE VIEW LANDING

MINIMUMS

PILOT BRIEFING

INFORMATION

TOP MARGIN IDENTIFICATION

AIRPORT DIAGRAM

Approach lighting (this is U.S. 

configuration sequenced 

flashing, see FIH)

Missed approach icons

BOTTOM MARGIN IDENTIFICATION

Latitude/longitude coordinates Airport identifier

Missed approach verbiage

Amendments

Time and speed table

City and state Issue # (issue authority)
4-11

Figure 4-4. Procedure identification. 010 to 16 DEC 2010 SC-5, 18 NO

NOT FOR NAVIGATION

be flown with a global positioning system (GPS) to the 

same runway, they are significantly different (e.g., one is 

a Required Navigation Performance (RNP) Authorization 

Required (AR) formally known as SPECIAL AIRCRAFT & 

AIRCREW AUTHORIZATION REQUIRED (SAAAR);” one has 

circling minimums and the other does not; the minimums 

are different; and the missed approaches are not the same). 

The approach procedure labeled Z has lower landing 

minimums than Y (some older charts may not reflect this).

In this example, the LNAV MDA for the RNAV (GPS) Z RWY 

13C has the lowest minimums of either approach due to 

the differences in the final approach required obstacle 

clearance (ROC) evaluation. This convention also eliminates 

any confusion with approach procedures labeled A and 

B, where only circling minimums are published. The 

designation of two area navigation (RNAV) procedures 

to the same runway can occur when it is desirable to 

accommodate panel mounted GPS receivers and flight 

management systems (FMSs), both with and without 

vertical navigation (VNAV). It is also important to note that 

only one of each type of approach for a runway, including 

ILS, VHF omnidirectional range (VOR), and non-directional 

beacon (NDB) can be coded into a database. 

Circling-Only Procedures 

Approaches that do not have straight-in landing minimums 

are identified by the type of approach followed by a letter.

Examples in Figure 4-6 show four procedure titles at the 

same airport that have only circling minimums. 

As can be seen from the example, the first approach of 

this type created at the airport is labeled with the letter A, 

and the lettering continues in alphabetical order. Typically, 

circling only approaches are designed for one of the 

following reasons: 

•	 The final approach course alignment with the

runway centerline exceeds 30°. 

•	 The descent gradient is greater than 400 feet per

nautical mile (FPNM) from the FAF to the threshold 

crossing height (TCH). When this maximum gradient 

is exceeded, the circling only approach procedure 

may be designed to meet the gradient criteria 

limits. This does not preclude a straight-in landing 

if a normal descent and landing can be made in 

accordance with the applicable CFRs. 

•	 A runway is not clearly defined on the airfield.

Communications 

The communication strip provided near the top of FAA 

approach charts gives flight crews the frequencies that 

they can expect to be assigned during the approach. 

The frequencies are listed in the logical order of use from 

arrival to touchdown. Having this information immediately 

available during the approach reduces the chances of a 

loss of contact between ATC and flight crews during this 

critical phase of flight. 

It is important for flight crews to understand their 

responsibilities with regard to communications in the 

various approach environments. There are numerous 

differences in communication responsibilities when 

operating into and out of airports without ATC towers 

as compared to airports with control towers. Today’s 

pilots face an increasing range of ATC environments and 

conflicting traffic dangers, making approach briefing and 

preplanning more critical. Individual company operating 

manuals and SOPs dictate the duties for each crewmember. 

Advisory Circular (AC) 120-71, Standard Operating 

Procedures for Flight Deck Crewmembers, contains the 

following concerning ATC communications: SOPs should 

state who (Pilot Flying (PF), Pilot Monitoring (PM), Flight 

Engineer (FE/SO)) handles the radios for each phase of 

flight, as follows:

•	 PF makesinputto aircraft/autopilot and/or verbally

states clearances while PM confirms input is what he 

or she read back to ATC.

•	 Any confusion in the flight deck is immediately
4-12

Figure 4-5. Multiple approaches.

EC-3, 18 NOV 2010 to 16 DEC 2010

0102 CED61 ot 0102 VON81, 3- CE

EC-3, 18 NOV 2010 to 16 DEC 2010

0102 CED61 ot 0102 VON81, 3- CE

NOT FOR NAVIGATION
4-13

Figure 4-6. Procedures with circling landing minima.

NW-1, 18 NOV 2010 to 16

OV 2010 to 16 DEC 2010

NW-1, 1

C 201

NOT FOR NAVIGATION

0

cleared up by requesting ATC confirmation.

•	 If any crewmember is off the flight deck, all ATC

instructions are briefed upon his or her return. Or, 

if any crewmember is off the flight deck, all ATC 

instructions are written down until his or her return 

and then passed to that crewmember upon return. 

Similarly, if a crewmember is off ATC frequency when 

making a precision approach (PA) announcement 

or when talking on company frequency, all ATC 

instructions are briefed upon his or her return.

•	 Company policy should address use of speakers,

headsets, boom microphone, and/or hand-held 

microphone.

•	 SOPsshould state the altitude awareness company

policy on confirming assigned altitude.

Example: The PM acknowledges ATC altitude clearance. If 

the aircraft is on the autopilot, then the PF makes input into 

the autopilot/altitude alerter. PF points to the input while 

stating the assigned altitude as he or she understands it. 

The PM then points to the input stating aloud what he or 

she understands the ATC clearance to be confirming that 

the input and clearance match. If the aircraft is being handflown, then the PM makes the input into the altitude alerter/

autopilot, then points to the input and states clearance. 

PF then points to the alerter stating aloud what he or she 

understands the ATC clearance to be confirming that the 

alerter and clearance match.

Example: If there is no altitude alerter in the aircraft, then 

both pilots write down the clearance, confirm that they 

have the same altitude, and then cross off the previously 

assigned altitude.

Approach Control 

Approach control is responsible for controlling all 

instrument flights operating within its area of responsibility. 

Approach control may serve one or more airports. Control 

is exercised primarily through direct pilot and controller 

communication and airport surveillance radar (ASR). Prior 

to arriving at the initial approach fix (IAF), instructions will 

be received from the air route traffic control center (ARTCC) 

to contact approach control on a specified frequency. 

Where radar is approved for approach control service, it is 

used not only for radar approaches, but also for vectors in 

conjunction with published non-radar approaches using 

conventional NAVAIDs or RNAV/GPS.

When radar handoffs are initiated between the ARTCC 

and approach control, or between two approach control 

facilities, aircraft are cleared (with vertical separation) to 

an outer fix most appropriate to the route being flown 

and, if required, given holding instructions. Or, aircraft 

are cleared to the airport or to a fix so located that the 

handoff is completed prior to the time the aircraft reaches 

the fix. When radar handoffs are used, successive arriving 

flights may be handed off to approach control with radar 

separation in lieu of vertical separation.

After release to approach control, aircraft are vectored 

to the final approach course. ATC occasionally vectors 

the aircraft across the final approach course for spacing 

requirements. The pilot is not expected to turn inbound 

on the final approach course unless an approach clearance 

has been issued. This clearance is normally issued with the 

final vector for interception of the final approach course, 

and the vector enables the pilot to establish the aircraft on 

the final approach course prior to reaching the FAF.

Air Route Traffic Control Center (ARTCC)

ARTCCs are approved for and may provide approach 

control services to specific airports. The radar systems used 

by these centers do not provide the same precision as an 

ASR or precision approach radar (PAR) used by approach 

control facilities and control towers, and the update rate 

is not as fast. Therefore, pilots may be requested to report 

established on the final approach course. Whether aircraft 

are vectored to the appropriate final approach course or 

provide their own navigation on published routes to it, 

radar service is automatically terminated when the landing 

is completed; or when instructed to change to advisory 

frequency at airports without an operating ATC tower, 

whichever occurs first. When arriving on an IFR flight plan 

at an airport with an operating control tower, the flight 

plan is closed automatically upon landing. 

The extent of services provided by approach control varies 

greatly from location to location. The majority of Part 121 

operations in the NAS use airports that have radar service 

and approach control facilities to assist in the safe arrival 

and departure of large numbers of aircraft. Many airports 
4-14

Figure 4-7. Durango approach and low altitude en route excerpt.

SW-1, 18 NOV 2010 to 16 DEC 2010

SW-1, 18 NOV 2010 to 16 DEC 2010

do not have approach control facilities. It is important for 

pilots to understand the differences between approaches 

with and without an approach control facility. For example, 

consider the Durango, Colorado, ILS DME RWY 2 and low 

altitude en route chart excerpt shown in Figure 4-7.

High or Lack of Minimum Vectoring Altitudes 

(MVAs)

Considering the fact that most modern commercial and 

corporate aircraft are capable of direct, point-to-point flight, 

it is increasingly important for pilots to understand the 

limitations of ARTCC capabilities with regard to minimum 

altitudes. There are many airports that are below the 

coverage area of Center radar, and, therefore, off-route 

transitions into the approach environment may require 

that the aircraft be flown at a higher altitude than would be 

required for an on-route transition. In the Durango example, 

an airplane approaching from the northeast on a direct 

route to the Durango VOR may be restricted to a minimum 

IFR altitude (MIA) of 17,000 feet mean sea level (MSL) due to 

unavailability of Center radar coverage in that area at lower 

altitudes. An arrival on V95 from the northeast would be 

able to descend to a minimum en route altitude (MEA) of 

12,000 feet, allowing a shallower transition to the approach 
4-15

environment. An off-route arrival may necessitate a descent 

into holding in order to avoid an unstable approach to 

Durango. 

Lack of Approach Control Terrain Advisories

Flight crews must understand that terrain clearance cannot 

be assured by ATC when aircraft are operating at altitudes 

that are not served by Center or approach radar. Recent 

National Transportation Safety Board (NTSB) investigations 

have identified several accidents that involved controlled 

flight into terrain (CFIT) by IFR rated and VFR pilots 

operating under visual flight conditions at night in remote 

areas. In many of these cases, the pilots were in contact with 

ATC at the time of the accident and receiving radar service. 

The pilots and controllers involved all appear to have been 

unaware that the aircraft were in danger. Increased altitude 

awareness and better preflight planning would likely have 

prevented all of these accidents. How can pilots avoid 

becoming involved in a CFIT accident?

CFIT accidents are best avoided through proper preflight 

planning.

•	 Terrain familiarization is critical to safe visual

operations at night. Use sectional charts or other 

topographic references to ensure that your altitude 

safely clears terrain and obstructions all along your 

route.

•	 In remote areas, especially in overcast or moonless

conditions, be aware that darkness may render visual 

avoidance of high terrain nearly impossible and that 

the absence of ground lights may result in loss of 

horizon reference.

•	 When planning a nighttime VFR flight, follow IFR

practices, such as climbing on a known safe course, 

until well above surrounding terrain. Choose a 

cruising altitude that provides terrain separation 

similar to IFR flights (2,000 feet AGL in mountainous 

areas and 1,000 feet above the ground in other areas.)

•	 Whenreceivingradarservices,donotdependonATC

to warn you of terrain hazards. Although controllers 

try to warn pilots if they notice a hazardous situation, 

they may not always be able to recognize that a 

particular VFR aircraft is dangerously close to terrain.

•	 When issued a heading along with an instruction to

“maintain VFR,” be aware that the heading may not 

provide adequate terrain clearance. If you have any 

doubt about your ability to visually avoid terrain and 

obstacles, advise ATC immediately and take action to 

reach a safe altitude if necessary.

•	 ATCradarsoftwarecanprovidelimitedpredictionand

warning of terrain hazards, but the warning system 

is configured to protect IFR flights and is normally 

suppressed for VFR aircraft. Controllers can activate 

the warning system for VFR flights upon pilot request, 

but it may produce numerous false alarms for aircraft 

operating below the MIA, especially in en route center 

airspace.

•	 If you fly at night, especially in remote or unlit areas,

consider whether a GPS-based terrain awareness unit 

would improve your safety of flight.

•	 Lack of approach control traffic advisories—if radar

service is not available for the approach, the ability 

of ATC to give flight crews accurate traffic advisories 

is greatly diminished. In some cases, the common 

traffic advisory frequency (CTAF) may be the only tool 

available to enhance an IFR flight’s awareness of traffic 

at the destination airport. Additionally, ATC will not 

clear an IFR flight for an approach until the preceding 

aircraft on the approach has cancelled IFR, either on 

the ground, or airborne once in visual meteorological 

conditions (VMC).

Airports With an ATC Tower 

Control towers are responsible for the safe, orderly, and 

expeditious flow of all traffic that is landing, taking off, 

operating on and in the vicinity of an airport and, when 

the responsibility has been delegated, towers also provide 

for the separation of IFR aircraft in terminal areas. Aircraft 

that are departing IFR are integrated into the departure 

sequence by the tower. Prior to takeoff, the tower controller 

coordinates with departure control to assure adequate 

aircraft spacing. 

Airports Without A Control Tower 

From a communications standpoint, executing an 

instrument approach to an airport that is not served by an 

ATC tower requires more attention and care than making 

a visual approach to that airport. Pilots are expected to 

self-announce their arrival into the vicinity of the airport 

no later than 10 NM from the field. Depending on the 

weather, as well as the amount and type of conflicting 

traffic that exists in the area, an approach to an airport 

without an operating ATC tower increases the difficulty of 

the transition to visual flight.

In many cases, a flight arriving via an instrument approach 

needs to mix in with VFR traffic operating in the vicinity 

of the field. For this reason, many companies require that 

flight crews make contact with the arrival airport CTAF or 

company operations personnel via a secondary radio over 

25 NM from the field in order to receive traffic advisories. 
4-16

NW-1, 18 NO

V 2010 to 16 DEC 2010

NW-1, 18 NO

V 2010 to 16 DEC 2010

NOT FOR NAVIGATION

Figure 4-8. Cheyenne Regional (KCYS), Cheyenne, Wyoming, ILS or LOC RWY 27.

In addition, pilots should attempt to listen to the CTAF 

well in advance of their arrival in order to determine the 

VFR traffic situation.

Since separation cannot be provided by ATC between 

IFR and VFR traffic when operating in areas where there 

is no radar coverage, pilots are expected to make radio 

announcements on the CTAF. These announcements 

allow other aircraft operating in the vicinity to plan their 

departures and arrivals with a minimum of conflicts. 

In addition, it is very important for crews to maintain a 

listening watch on the CTAF to increase their awareness 

of the current traffic situation. Flights inbound on an 

instrument approach to a field without a control tower 

should make several self-announced radio calls during 

the approach: 

•	 Initial call within 4-10 minutes ofthe aircraft’s arrival

at the IAF. This call should give the aircraft’s location 

as well as the crew’s approach intentions.

•	 Departing the IAF,stating the approach thatis being

initiated.

•	 Procedure turn (or equivalent) inbound.

•	 FAF inbound,stating intended landing runway and

maneuvering direction if circling.

•	 Short final, giving traffic on the surface notification

of imminent landing.

When operating on an IFR flight plan at an airport without 

a functioning control tower, pilots must initiate cancellation 

of the IFR flight plan with ATC or an AFSS. Remote 
4-17

communications outlets (RCOs) or ground communications 

outlets (GCOs), if available, can be used to contact an ARTCC 

or an AFSS after landing. If a frequency is not available on 

the ground, the pilot has the option to cancel IFR while 

in flight if VFR conditions can be maintained while in 

contact with ARTCC, as long as those conditions can be 

maintained until landing. Additionally, pilots can relay a 

message through another aircraft or contact flight service 

via telephone.

Primary NAVAID

Most conventional approach procedures are built around 

a primary final approach NAVAID; others, such as RNAV 

(GPS) approaches, are not. If a primary NAVAID exists for 

an approach, it should be included in the IAP briefing, set 

into the appropriate backup or active navigation radio, and 

positively identified at some point prior to being used for 

course guidance. Adequate thought should be given to the 

appropriate transition point for changing from FMS or other 

en route navigation over to the conventional navigation to 

be used on the approach. Specific company standards and 

procedures normally dictate when this changeover occurs; 

some carriers are authorized to use FMS course guidance 

throughout the approach, provided that an indication 

of the conventional navigation guidance is available 

and displayed. Many carriers, or specific carrier fleets, 

are required to change over from RNAV to conventional 

navigation prior to the FAF of an instrument approach.

Depending on the complexity of the approach procedure, 

pilots may have to brief the transition from an initial NAVAID 

to the primary and missed approach NAVAIDs. Figure 4-8 

shows the Cheyenne, Wyoming, ILS Runway 27 approach 

procedure, which requires additional consideration during 

an IAP briefing.

If the 15 DME arc of the CYS VOR is to be used as the 

transition to this ILS approach procedure, caution must 

be paid to the transition from en route navigation to the 

initial NAVAID and then to the primary NAVAID for the ILS 

approach. Planning when the transition to each of these 

NAVAIDs occurs may prevent the use of the incorrect 

NAVAID for course guidance during approaches where 

high pilot workloads already exist.

Equipment Requirements

The navigation equipment that is required to join and fly an 

IAP is indicated by the title of the procedure and notes on 

the chart. Straight-in IAPs are identified by the navigation 

system by providing the final approach guidance and the 

runway with which the approach is aligned (for example, 

VOR RWY 13). Circling-only approaches are identified 

by the navigation system by providing final approach 

guidance and a letter (for example, VOR A). More than one 

navigation system separated by a slant indicates that more 

than one type of equipment must be used to execute the 

final approach (for example, VOR/DME RWY 31). More than 

one navigation system separated by the word “or” indicates 

either type of equipment can be used to execute the final 

approach (for example, VOR or GPS RWY 15).

In some cases, other types of navigation systems, 

including radar, are required to execute other portions of 

the approach or to navigate to the IAF (for example, an 

NDB procedure turn to an ILS, or an NDB in the missed 

approach, or radar required to join the procedure or identify 

a fix). When ATC radar or other equipment is required for 

procedure entry from the en route environment, a note is 

charted in the plan view of the approach procedure chart 

(for example, RADAR REQUIRED or AUTOMATIC DIRECTION 

FINDER (ADF) REQUIRED). When radar or other equipment 

is required on portions of the procedure outside the final 

approach segment, including the missed approach, a note 

is charted in the notes box of the pilot briefing portion 

of the approach chart (for example, RADAR REQUIRED or 

DISTANCE MEASURING EQUIPMENT (DME) REQUIRED). 

Notes are not charted when VOR is required outside the 

final approach segment. Pilots should ensure that the 

aircraft is equipped with the required NAVAIDs to execute 

the approach, including the missed approach. Refer to the 

AIM paragraph 5-4-5 for additional options with regards to 

equipment requirements for IAPs.

RNAV systems may be used as a Substitute Means of 

Navigation when a very high frequency (VHF) Omnidirectional Range (VOR), Distance Measuring Equipment 

(DME), Tactical Air Navigation (TACAN), VOR/TACAN 

(VORTAC), VOR/DME, non-directional radio beacon (NDB), 

or compass locator facility including locator outer

marker and locator middle marker is out-of-service, i.e., the 

Navigation Aid (NAVAID) information is not available; an 

aircraft is not equipped with an automatic direction finder 

(ADF) or DME; or the installed ADF or DME on an aircraft is 

not operational. For example, if equipped with a suitable 

RNAV system, a pilot may hold over an out-of-service NDB. 

Refer to Advisory Circular 90-108, Use of Suitable RNAV 

System on Conventional Routes and Procedures, dated 

March 3, 2011 for additional guidance on the proper times 

and procedures for substituting a RNAV system for means 

of navigation.

Courses

Traditional Courses

An aircraft that has been cleared to a holding fix and 

subsequently “cleared...approach,” normally does not 
4-18

0102 CED61 ot 0102 VON81, 4- WS

NOT FOR NAVIGATION

SW-4, 18 NOV 2010 to 16 DEC 2010

Figure 4-9. Fly-by and fly-over waypoints.

receive new routing. Even though clearance for the 

approach may have been issued prior to the aircraft 

reaching the holding fix, ATC would expect the pilot to 

proceed via the holding fix that was the last assigned route, 

and the feeder route associated with that fix, if a feeder 

route is published on the approach chart, to the IAF to 

commence the approach. When cleared for the approach, 

the published off-airway (feeder) routes that lead from 

the en route structure to the IAF are part of the approach 

clearance.

If a feeder route to an IAF begins at a fix located along 

the route of flight prior to reaching the holding fix, 

and clearance for an approach is issued, a pilot should 

commence the approach via the published feeder route. 

For example, the aircraft would not be expected to overfly 

the feeder route and return to it. The pilot is expected to 

commence the approach in a similar manner at the IAF, 

if the IAF for the procedure is located along the route of 

flight to the holding fix.

If a route of flight directly to the IAF is desired, it should 

be so stated by the controller with phraseology to include 

the words “direct,” “proceed direct,” or a similar phrase 

that the pilot can interpret without question. When a 

pilot is uncertain of the clearance, ATC should be queried 

immediately as to what route of flight is preferred.

The name of an instrument approach, as published, is 

used to identify the approach, even if a component of the 

approach aid is inoperative or unreliable. The controller 

will use the name of the approach as published, but must 

advise the aircraft at the time an approach clearance is 

issued that the inoperative or unreliable approach aid 

component is unusable. (Example: “Cleared ILS RWY 4, 

glideslope unusable.”) 

Area Navigation Courses 

RNAV (GPS) approach procedures introduce their own 

tracking issues because they are flown using an onboard 

navigation database. They may be flown as coupled 

approaches or flown manually. In either case, navigation

system coding is based on procedure design, including 

waypoint (WP) sequencing for an approach and missed 

approach. The procedure design indicates whether the WP 

is a fly-over (FO) or fly-by (FB), and provides appropriate 

guidance for each. A FB WP requires the use of turn 

anticipation to avoid overshooting the next flight segment. 
4-19

A FO WP precludes any turn until the WP is over flown and 

is followed by either an intercept maneuver of the next 

flight segment or direct flight to the next WP.

Approach waypoints, except for the missed approach 

waypoint (MAWP) and the missed approach holding 

waypoint (MAHWP), are normally FB WPs. Notice that in the 

plan view in Figure 4-9, there are four FB WPs, but only the 

circled WP symbol at PRINO is a FO WP. If flying manually to 

a selected RNAV WP, pilots should anticipate the turn at a FB 

WP to ensure a smooth transition and avoid overshooting 

the next flight segment. Alternatively, for a FO WP, no turn 

is accomplished until the aircraft passes the WP.

There are circumstances when a WP may be coded into the 

database as both a FB WP and a FO WP, depending on how 

the WPs are sequenced during the approach procedure. For 

example, a WP that serves as an IAF may be coded as a FB

WP for the approach and as a FO WP when it also serves 

as the MAWP for the missed approach procedure (MAP). 

This is just one reason why instrument approaches should 

be loaded in their entirety from the FMS and not manually 

built or modified.

Altitudes 

Prescribed altitudes may be depicted in four different 

configurations: minimum, maximum, recommended, and 

mandatory. The U.S. Government distributes approach 

charts produced by the FAA. Altitudes are depicted on 

these charts in the profile view with an underscore or 

overscore, or both to identify them as minimum, maximum, 

or mandatory, respectively.

•	 Minimumaltitudesaredepictedwiththealtitudevalue

underscored. Aircraft are required to maintain altitude 

at or above the depicted value (e.g., 3000).

•	 Maximumaltitudesaredepictedwiththealtitudevalue

overscored. Aircraft are required to maintain altitude 

at or below the depicted value (e.g., 4800). 

•	 Mandatoryaltitudesaredepictedwiththealtitudevalue

both underscored and overscored. Aircraft are required 

to maintain altitude at the depicted value (e.g., 5500). 

•	 Recommended altitudes are depicted without an

underscore or overscore. 

NOTE: Pilots are cautioned to adhere to altitudes as 

prescribed because, in certain instances, they may be used 

as the basis for vertical separation of aircraft by ATC. If a 

depicted altitude is specified in the ATC clearance, that 

altitude becomes mandatory as defined above.

Minimum Safe Altitude 

Minimum safe altitudes (MSAs) are published for emergency 

use on IAP charts. For conventional navigation systems, the 

MSA is normally based on the primary omnidirectional 

facility on which the IAP is predicated. The MSA depiction 

on the approach chart contains the facility identifier of the 

NAVAID used to determine the MSA. For RNAV approaches, 

the MSA is based on either the runway waypoint (RWY 

WP), the MAWP for straight-in approaches, or the airport 

waypoint (APT WP) for circling only approaches. For RNAV 

(GPS) approaches with a terminal arrival area (TAA), the 

MSA is based on the IAF WP.

MSAs are expressed in feet above MSL and normally 

have a 25 NM radius. This radius may be expanded to 

30 NM if necessary to encompass the airport landing 

surfaces. Ideally, a single sector altitude is established 

and depicted on the plan view of approach charts. When 

necessary to maintain clearance from obstructions, the 

area may be further sectored and as many as four MSAs 

established. When established, sectors may be no less 

than 90° in spread. MSAs provide 1,000 feet clearance over 

all obstructions but do not necessarily assure acceptable 

navigation signal coverage.

Final Approach Fix Altitude 

Another important altitude that should be briefed during 

an IAP briefing is the FAF altitude, designated by the 

cross on a non-precision approach, and the lightning bolt 

symbol designating the glideslope intercept altitude on 

a precision approach. Adherence and cross-check of this 

altitude can have a direct effect on the success and safety 

of an approach.

Proper airspeed, altitude, and configuration, when crossing 

the FAF of a non-precision approach, are extremely 

important no matter what type of aircraft is being flown. 

The stabilized approach concept, implemented by the 

FAA within the SOPs of each air carrier, suggests that 

crossing the FAF at the published altitude is often a critical 

component of a successful non-precision approach, 

especially in a large turbojet aircraft.

The glideslope intercept altitude of a precision approach 

should also be included in the IAP briefing. Awareness of 

this altitude when intercepting the glideslope can ensure 

the flight crew that a “false glideslope” or other erroneous 

indication is not inadvertently followed. Many air carriers 

include a standard callout when the aircraft passes over the 

FAF of the non-precision approach underlying the ILS. The 

PM states the name of the fix and the charted glideslope 

altitude, thus allowing both pilots to cross-check their 

respective altimeters and verify the correct indications.
4-20

Pilot’s view without EVS-4000 Pilot’s view with EVS-4000

Figure 4-10. Enhanced flight vision system.

Minimum Descent Altitude (MDA), Decision 

Altitude (DA), And Decision Height (DH)

MDA—the lowest altitude, expressed in feet MSL, to which 

descent is authorized on final approach or during circle-toland maneuvering in execution of a standard instrument 

approach procedure (SIAP) where no electronic glideslope 

is provided.

DA—a specified altitude in the precision approach at 

which a missed approach must be initiated if the required 

visual reference to continue the approach has not been 

established.

DH—with respect to the operation of aircraft, means the 

height at which a decision must be made during an ILS, MLS, 

or PAR IAP to either continue the approach or to execute a 

missed approach.

CAT II and III approach DHs are referenced to AGL and

measured with a radio altimeter.

The height above touchdown (HAT) for a CAT I precision 

approach is normally 200 feet above touchdown zone 

elevation (TDZE). When a HAT of 250 feet or higher is 

published, it may be the result of the signal-in-space 

coverage, or there may be penetrations of either the final 

or missed approach obstacle clearance surfaces (OCSs). 

If there are OCS penetrations, the pilot has no indication 

on the approach chart where the obstacles are located. It 

is important for pilots to brief the MDA, DA, or DH so that 

there is no ambiguity as to what minimums are being used. 

These altitudes can be restricted by many factors. Approach 

category, inoperative equipment in the aircraft or on the 

ground, crew qualifications, and company authorizations 

are all examples of issues that may limit or change the 

height of a published MDA, DA, or DH.

For many air carriers, OpSpecs may be the limiting factor 

for some types of approaches. NDB and circling approaches 

are two common examples where the OpSpecs minimum 

listed altitudes may be more restrictive than the published 

minimums. Many Part 121 and 135 operators are restricted 

from conducting circling approaches below 1,000 feet 

MDA and 3 SM visibility by Part C of their OpSpecs, 

and many have specific visibility criteria listed for NDB 

approaches that exceed visibilities published for the 

approach (commonly 2 SM). In these cases, flight crews 

must determine which is the more restrictive of the two 

and comply with those minimums.

In some cases, flight crew qualifications can be the limiting 

factor for the MDA, DA, or DH for an instrument approach. 

There are many CAT II and III approach procedures 

authorized at airports throughout the United States, but 

RNP AR restricts their use to pilots who have received 

specific training, and aircraft that are equipped and 

authorized to conduct those approaches. Other rules 

pertaining to flight crew qualifications can also determine 

the lowest usable MDA, DA, or DH for a specific approach. 

14 CFR Part 121, section 121.652, 14 CFR Part 125, section 

125.379, and 14 CFR Part 135, section 135.225 require 

that some PICs, with limited experience in the aircraft 

they are operating, increase the approach minimums and 

visibility by 100 feet and one- half mile respectively. Rules 

for these “high-minimums” pilots are usually derived from 

a combination of federal regulations and the company’s 

OpSpecs. There are many factors that can determine the 

actual minimums that can be used for a specific approach. 

All of them must be considered by pilots during the 

preflight and approach planning phases, discussed, and 

briefed appropriately. 

Pilots are cautioned to fully understand and abide by 

the guidelines set forth in 91.175(c) regarding proper 

identification of the runway and runway environment when 

electing to continue any approach beyond the published 

DA/DH or MDA.

It is imperative to recognize that any delay in making a 

decision to execute the Missed Approach Procedure at 

the DA/DH or MDA/Missed Approach Point will put the 

aircrew at risk of impacting any obstructions that may be 

penetrating the visual obstacle clearance surface

The visual segment of an IAP begins at DA or MDA and 

continues to the runway. There are two means of operating 

in the visual segment, one is by using natural vision under

14 CFR Part 91, section 91.175 (c) and the other is by using 

an Enhanced Flight Vision System under 14 CFR Part 91, 

section 91.175 (l). 
4-21

Enhanced Flight Vision Systems (EFVS) and 

Instrument Approaches

An Enhanced Flight Vision System (EFVS) is an installed 

airborne system that uses an electronic means to provide 

a display of the forward external scene topography (the 

applicable natural or manmade features of a place or 

region especially in a way to show their relative positions 

and elevation) through the use of imaging sensors, such 

as forward looking infrared, millimeter wave radiometry, 

millimeter wave radar, and/or low light level image 

intensifying. The EFVS imagery is displayed along with the 

additional flight information and aircraft flight symbology 

required by 14 CFR Part 91, section 91.175(m) on a headup display (HUD), or an equivalent display, in the same 

scale and alignment as the external view and includes the 

display element, sensors, computers and power supplies, 

indications, and controls. [Figure 4-10]

When the runway environment cannot be visually acquired 

at the DA or MDA using natural vision, a pilot may use an 

EFVS to descend below DA or MDA down to 100 feet above 

the TDZE, provided the pilot determines that the enhanced 

flight visibility (EFV) observed by using the EFVS is not less 

than the minimum visibility prescribed in the IAP being 

flown, the pilot acquires the required visual references 

prescribed in 14 CFR Part 91, section 91.175 (l)(3), and all 

of the other requirements of 14 CFR Part 91, section 91.175 

(l) and (m) are met. The primary reference for maneuvering 

the aircraft is based on what the pilot sees through the 

EFVS. At 100 feet above the TDZE, a pilot can continue to 

descend only when the visual reference requirements for 

descent below 100 feet can be seen using natural vision 

(without the aid of the EFVS). In other words, a pilot may 

not continue to rely on the EFVS sensor image to identify 

the required visual references below 100 feet above the 

TDZE. Supporting information is provided by the flight 

path vector (FPV) cue, flight path angle (FPA) reference 

cue, onboard navigation system, and other imagery and 

flight symbology displayed on the HUD. The FPV and FPA 

reference cues, along with the EFVS imagery of the TDZ, 

provide the primary vertical path reference for the pilot 

when vertical guidance from a precision approach or 

approach with vertical guidance is not available.

An EFVS may be used to descend below DA or MDA from 

any straight-in IAP, other than Category II or Category III 

approaches, provided all of the requirements of 14 CFR 

Part 91, section 91.175 (l) are met. This includes straight-in 

precision approaches, approaches with vertical guidance 

(localizer performance with vertical guidance (LPV) or 

lateral navigation (LNAV)/vertical navigation (VNAV)), 

and non-precision approaches (VOR, NDB, localizer (LOC), 

RNAV, GPS, localizer type directional aid (LDA), simplified 

directional facility (SDF)). An instrument approach with a 

circle-to-land maneuver or circle-to-land minimums does 

not meet criteria for straight-in landing minimums. While 

the regulations do not prohibit EFVS from being used 

during any phase of flight, they do prohibit it from being 

used for operational credit on anything but a straight-in 

IAP with straight-in landing minima. EFVS may only be 

used during a circle-to-land maneuver provided the visual 

references required throughout the circling maneuver are 

distinctly visible using natural vision. An EFVS cannot be 

used to satisfy the requirement that an identifiable part of 

the airport be distinctly visible to the pilot during a circling 

maneuver at or above MDA or while descending below 

MDA from a circling maneuver.

The EFVS visual reference requirements of 14 CFR Part 91, 

section 91.175 (l)(3) comprise a more stringent standard than 

the visual reference requirements prescribed under 14 CFR 

Part 91, section 91.175 (c)(3) when using natural vision. The 

more stringent standard is needed because an EFVS might 

not display the color of the lights used to identify specific 

portions of the runway or might not be able to consistently 

display the runway markings. The main differences for EFVS 

operations are that the visual glideslope indicator (VGSI) 

lights cannot be used as a visual reference, and specific 

visual references from both the threshold and TDZ must 

be distinctly visible and identifiable. However, when using 

natural vision, only one of the specified visual references 

must be visible and identifiable.

Pilots must be especially knowledgeable of the approach 

conditions and approach course alignment when considering 

whether to rely on EFVS during a non-precision approach 

with an offset final approach course. Depending upon 

the combination of crosswind correction and the lateral 

field of view provided by a particular EFVS, the required 

visual references may or may not be within the pilot’s view 

looking through the EFVS display. Pilots conducting any 

non-precision approach must verify lateral alignment with 

the runway centerline when determining when to descend 

from the MDA.

Any pilot operating an aircraft with an EFVS installed should 

be aware that the requirements of 14 CFR Part 91, section

91.175 (c) for using natural vision, and the requirements of 14

CFR Part 91, section 91.175 (l) for using EFVS are different. 

A pilot would, therefore, first have to determine whether 

an approach is commenced using natural vision or using 

EFVS. While these two sets of requirements provide a 

parallel decision making process, the requirements for 

when a missed approach must be executed differ. Using 

EFVS, a missed approach must be initiated at or below DA 

or MDA down to 100 feet above TDZE whenever the pilot 

determines that:
4-22

o 16 DEC 2010

EC-2, 18 NO

V 20

NOT FOR NAVIGATION

Figure 4-11. VNAV information.

1. The enhanced flight visibility is less than the visibility 

minima prescribed for the IAP being used;

2. The required visual references for the runway of 

intended landing are no longer distinctly visible and 

identifiable to the pilot using the EFVS imagery;

3. The aircraft is not continuously in a position from 

which a descent to a landing can be made on the 

intended runway, at a normal rate of descent, using 

normal maneuvers; or

4. For operations under 14 CFR Part 121 and 135, 

the descent rate of the aircraft would not allow 

touchdown to occur within the TDZ of the runway 

of intended landing.

It should be noted that a missed approach after passing

the DA, or beyond the MAP, involves additional risk until

established on the published missed approach segment. 

Initiating a go-around after passing the published MAP may 

result in loss of obstacle clearance. As with any approach, 

pilot planning should include contingencies between the 

published MAP and touchdown with reference to obstacle 

clearance, aircraft performance, and alternate escape plans. 

At and below 100 feet above the TDZE, the regulations 

do not require the EFVS to be turned off or the display 

to be stowed in order to continue to a landing. A pilot 

may continue the approach below this altitude using an 

EFVS as long as the required visual references can be seen 

through the display using natural vision. An operator may 

not continue to descend beyond this point by relying 

solely on the sensor image displayed on the EFVS. In order 

to descend below 100 feet above the TDZE, the flight 

visibility assessed using natural vision must be sufficient 

for the following visual references to be distinctly visible 

and identifiable to the pilot without reliance on the EFVS 

to continue to a landing:

1. The lights or markings of the threshold, or

2. The lights or markings of the TDZ.

It is important to note that from 100 feet above the TDZE 

and below, the flight visibility does not have to be equal 

to or greater than the visibility prescribed for the IAP in 

order to continue descending. It only has to be sufficient 

for the visual references required by 14 CFR Part 91, section 

91.175 (l)(4) to be distinctly visible and identifiable to the 
4-23

pilot without reliance on the EFVS.

A missed approach must be initiated when the pilot 

determines that:

1. The flight visibility is no longer sufficient to distinctly 

see and identify the required visual references listed 

in 14 CFR Part 91, section 91.175 (l)(4) using natural 

vision;

2. The aircraft is not continuously in a position from 

which a descent to a landing can be made on the 

intended runway, at a normal rate of descent, using 

normal maneuvers; or

3. For operations under 14 CFR Part 121 and 135, 

the descent rate of the aircraft would not allow 

touchdown to occur within the TDZ of the runway 

of intended landing.

While touchdown within the TDZ is not specifically 

addressed in the regulations for operators other than 

Part 121 and 135 operators, continued operations below 

DA or MDA where touchdown in the TDZ is not assured, 

where a high sink rate occurs, or where the decision to 

conduct a MAP is not executed in a timely manner, all 

create a significant risk to the operation. A missed approach 

initiated after the DA or MAP involves additional risk. At 

100 feet or less above the runway, it is likely that an aircraft 

is significantly below the TERPS missed approach obstacle 

clearance surface. Prior planning is recommended and 

should include contingencies between the published 

MAP and touchdown with reference to obstacle clearance, 

aircraft performance, and alternate escape plans. 

Vertical Navigation

One of the advantages of some GPS and multi-sensor FMS 

RNAV avionics is the advisory VNAV capability. Traditionally, 

the only way to get vertical path information during an 

approach was to use a ground-based precision NAVAID. 

Modern RNAV avionics can display an electronic vertical 

path that provides a constant-rate descent to minimums.

Since these systems are advisory and not primary guidance, 

the pilot must continuously ensure the aircraft remains at 

or above any published altitude constraint, including stepdown fix altitudes, using the primary barometric altimeter. 

The pilots, airplane, and operator must be approved to use 

advisory VNAV inside the FAF on an instrument approach.

VNAV information appears on selected conventional 

nonprecision, GPS, and RNAV approaches (see “Types of 

Approaches” later in this chapter). It normally consists of 

two fixes (the FAF and the landing runway threshold), a 

FAF crossing altitude, a vertical descent angle (VDA), and 

may provide a visual descent point (VDP). [Figure 4-11] The 

published VDA is for information only, advisory in nature, 

and provides no additional obstacle protection below the 

MDA. Operators can be approved to add a height loss value 

to the MDA, and use this derived decision altitude (DDA) 

to ensure staying above the MDA. Operators authorized to 

use a VNAV DA in lieu of the MDA must commence a missed 

approach immediately upon reaching the VNAV DA if the 

required visual references to continue the approach have 

not been established.

A constant-rate descent has many safety advantages over 

non-precision approaches that require multiple level-offs at 

stepdown fixes or manually calculating rates of descent. A 

stabilized approach can be maintained from the FAF to the 

landing when a constant-rate descent is used. Additionally, 

the use of an electronic vertical path produced by onboard 

avionics can serve to reduce CFIT, and minimize the 

effects of visual illusions on approach and landing. Some 

countries even mandate the use of continuous descent 

final approaches (CDFAs) on non-precision approaches.

Wide Area Augmentation System 

The Wide Area Augmentation System (WAAS) offers 

an opportunity for airports to gain ILS like approach 

capability without the purchase or installation of any 

ground-based navigation equipment at the airport. 

Today, WAAS is already being used at more than 900 

runways across the United States to achieve minimums 

as low as 200 feet height above HAT/one-half mile 

visibility.

Benefits Of WAAS In The Airport Environment

WAAS is a navigation service using a combination of GPS 

satellites and the WAAS geostationary satellites to improve 

the navigational service provided by GPS. WAAS achieved 

initial operating capability (IOC) in 2003. The system is 

owned and operated by the FAA and provided free of direct 

user charges to users across the United States and most of 

Canada and Mexico.

WAAS improves the navigational system accuracy for 

en route, terminal, and approach operations over all the 

continental United States and significant portions of Alaska, 

Canada, and Mexico. This new navigational technology 

supports vertically-guided instrument approaches to all 

qualifying runways in the United States. Vertically-guided 

approaches reduce pilot workload and provide safety 

benefits compared to non-precision approaches. The WAAS 

enabled vertically guided approach procedures are called 

LPV, which stands for “localizer performance with vertical 

guidance,” and provide ILS equivalent approach minimums 

as low as 200 feet at qualifying airports. Actual minimums 

are based on an airport’s current infrastructure, as well as 
4-24

SC-1, 10 M

AR 2011 to 07 APR 2011

SC-1, 10 M

AR 2011 to 07 APR 2011

NOT FOR NAVIGATION

Figure 4-12. RNAV GPS approach minima.
4-25

Ranging sources

Status information

GBAS reference receivers

GBAS ground facility

Omnidirectional VHF data broadcast (VDB) signal

GPS satellites

Differential corrections, integrity 

data and path definition

Figure 4-13. GBAS architecture.

an evaluation of any existing obstructions. The FAA plans to 

publish 300 WAAS approach procedures per year to provide 

service to all qualifying instrument runways within the NAS.

Advantages Of WAAS Enabled LPV Approaches

The advantages of WAAS enabled LPV approaches include:

•	 LPV procedures have no requirement for groundbased transmitters at the airport.

•	 Noconsiderationneedstobegiventotheplacement

of navigation facility, maintenance of clear zones 

around the facility, or access to the facility for 

maintenance.

•	 LPV approaches eliminate the need for critical area

limitations associated with an ILS.

•	 From a pilot’s viewpoint, an LPV approach looks

and flies like an ILS, but the WAAS approach is more 

stable than that of an ILS.

•	 WAAS equipped users can fly RNAV and basic

required navigation performance (RNP) procedures, 

as well as LPV procedures, and the avionics costs 

are relatively inexpensive considering the total 

navigation solution provided.

RNAV (GPS) approach charts presently can have up to four 

lines of approach minimums: LPV, LNAV/VNAV, LNAV, and 

Circling. Figure 4-12 shows how these minimums might 

be presented on an approach chart, with the exception of 

Global Navigation Satellite System Landing System (GLS). 

This enables as many GPS equipped aircraft to use the 

procedure as possible and provides operational flexibility 

if WAAS becomes unavailable. Some aircraft may only be 

equipped with GPS receivers so they can fly to the LNAV 

MDA. Some aircraft equipped with GPS and FMS (with 

approach-certified barometric vertical navigation, or BaroVNAV) can fly to the LNAV/VNAV MDA. Flying a WAAS LPV 

approach requires an aircraft with WAAS-LPV avionics. If 

for some reason the WAAS service becomes unavailable, all 

GPS or WAAS equipped aircraft can revert to the LNAV MDA 

and land safely using GPS only, which is available nearly 100 

percent of the time.

LPV identifies WAAS approach with vertical guidance (APV) 

approach minimums with electronic lateral and vertical 

guidance capability. LPV is used for approaches constructed 

with WAAS criteria where the value for the vertical alarm 

limit is more than 12 meters and less than 50 meters. 

WAAS avionics equipment approved for LPV approaches is 

required for this type of approach. The lateral guidance is 

equivalent to localizer accuracy, and the protected area is 

considerably smaller than the protected area for the present 

LNAV and LNAV/VNAV lateral protection. Aircraft can fly this 

minima line with a statement in the AFM that the installed 

equipment supports LPV approaches. In Figure 4-12, notice 

the WAAS information shown in the top left corner of the 
4-26

pilot briefing information on the chart depicted. Below the 

term WAAS is the WAAS channel number (CH 50102), and 

the WAAS approach identifier (W17A), indicating Runway 

17R in this case, and then a letter to designate the first in a 

series of procedures to that runway.

LNAV/VNAV identifies APV minimums developed to 

accommodate an RNAV IAP with vertical guidance, usually 

provided by approach certified Baro-VNAV, but with vertical 

and lateral integrity limits larger than a precision approach 

or LPV. Many RNAV systems that have RNP 0.3 or less 

approach capability are specifically approved in the AFM. 

Airplanes that are commonly approved in these types of 

operations include Boeing 737NG, 767, and 777, as well as 

the Airbus A300 series. Landing minimums are shown as 

DAs because the approaches are flown using an electronic 

glide path. Other RNAV systems require special approval. In 

some cases, the visibility minimums for LNAV/VNAV might 

be greater than those for LNAV only. This situation occurs 

because DA on the LNAV/VNAV vertical descent path is 

farther away from the runway threshold than the LNAV 

MDA missed approach point.

Also shown in Figure 4-12, is the LNAV minimums line. This 

minimum is for lateral navigation only, and the approach 

minimum altitude is published as a MDA. LNAV provides 

the same level of service as the present GPS stand alone 

approaches. LNAV supports the following systems: WAAS, 

when the navigation solution will not support vertical 

navigation; and GPS navigation systems which are 

presently authorized to conduct GPS approaches.

Circling minimums that may be used with any type of 

approach approved RNAV equipment when publication of 

straight-in approach minimums is not possible.

Ground-Based Augmentation System (GBAS)

The United States version of the Ground-Based 

Augmentation System (GBAS) has traditionally been 

referred to as the Local Area Augmentation System (LAAS). 

The worldwide community has adopted GBAS as the official 

term for this type of navigation system. To coincide with 

international terminology, the FAA is also adopting the term 

GBAS to be consistent with the international community. 

GBAS is a ground-based augmentation to GPS that focuses 

its service on the airport area (approximately a 20–30 mile 

radius) for precision approach, DPs, and terminal area 

operations. It broadcasts its correction message via a very 

high frequency (VHF) radio data link from a ground-based 

transmitter. GBAS yields the extremely high accuracy, 

availability, and integrity necessary for Category I, II, and 

III precision approachesand provides the ability for flexible, 

curved approach paths. GBAS demonstrated accuracy is 

less than one meter in both the horizontal and vertical 

axis. [Figure 4-13]

The GBAS augments the GPS to improve aircraft safety 

during airport approaches and landings. It is expected 

that the end state configuration will pinpoint the aircraft’s 

position to within one meter or less with a significant 

improvement in service flexibility and user operating costs.

GBAS is comprised of ground equipment and avionics. 

The ground equipment includes four reference receivers, a 

GBAS ground facility, and a VHF data broadcast transmitter. 

This ground equipment is complemented by GBAS avionics 

installed on the aircraft. Signals from GPS satellites are 

received by the GBAS GPS reference receivers (four 

receivers for each GBAS) at the GBAS equipped airport. 

The reference receivers calculate their position using GPS. 

The GPS reference receivers and GBAS ground facility work 

together to measure errors in GPS provided position.

The GBAS ground facility produces a GBAS correction 

message based on the difference between actual and GPS 

calculated position. Included in this message is suitable 

integrity parameters and approach path information. 

This GBAS correction message is then sent to a VHF data 

broadcast (VDB) transmitter. The VDB broadcasts the GBAS 

signal throughout the GBAS coverage area to avionics in 

GBAS equipped aircraft. GBAS provides its service to a 

local area (approximately a 20–30 mile radius). The signal 

coverage is designed support the aircraft’s transition from 

en route airspace into and throughout the terminal area 

airspace.

The GBAS equipment in the aircraft uses the corrections 

provided on position, velocity, and time to guide the 

aircraft safely to the runway. This signal provides ILS look 

alike guidance as low as 200 feet above touchdown. 

GBAS will eventually support landings all the way to the 

runway surface. Figure 4-14 is an example of a GBAS (LAAS) 

approach into Newark, New Jersey.

Required Navigation Performance (RNP)

The operational advantages of RNP include accuracy 

and integrity monitoring, which provide more precision 

and lower minimums than conventional RNAV. RNP DAs 

can be as low as 250 feet with visibilities as low as threefourths SM. Besides lower minimums, the benefits of 

RNP include improved obstacle clearance limits, as well 

as reduced pilot workload. When RNP capable aircraft fly 

an accurate, repeatable path, ATC can be confident that 

these aircraft are at a specific position, thus maximizing 

safety and increasing capacity.
4-27

NE-2, 16 DEC 2010 to 13 JAN 2011

NE-2, 16 DEC 2010 to 13 JAN 2011

NOT FOR NAVIGATION

Figure 4-14. GLS approach at Newark, New Jersey.
4-28

NE-3, 20 SEP 2012 to 18 OCT 2012

NE-3, 20 SEP 2012 to 18 OCT 2012

NOT FOR NAVIGATION

RNP procedures are sequenced in the same 

manner as RNAV (GPS) procedures.

Procedure title “RNAV” includes 

parenthetical “(RNP)” terminology.

RNP AR requirements are highlighted in large, bold print.

RNP-required sensors, FMS capabilities, and relevant 

procedure notes are included in the Pilot Briefing 

Information procedure notes section.

RF legs can be used in any segment of the procedure 

(transition, intermediate, final, or missed approach). 

RF leg turn directions (left or right) are not noted in the 

planview because the graphic depiction of the flight 

tracks is intuitive. Likewise, the arc centerpoints, arc 

radius, and associated RF leg performance limits—

such as bank angles and speeds—are not depicted 

because these aircraft performance characteristics 

are encoded in the navigation database.

On this particular procedure, lateral and vertical course guidance 

from the Decision Altitude (DA) to the Runway Waypoint (Landing 

Threshold Point or LTP) is provided by the aircraft's flight 

management system and onboard navigation database; however, 

any continued flight beyond and below the DA to the landing 

threshold is to be conducted under visual meteorological 

conditions (VMC).

RNP values for each individual 

leg of the procedure, defined by 

the procedure design criteria for 

containment purposes, are 

encoded into the aircraft's 

navigation database. Applicable 

landing minimums are shown in 

a normal manner along with the 

associated RNP value in the 

landing minimums section. When 

more than one set of RNP landing 

minimums is available and an 

aircrew is able to achieve lower 

RNP through approved means, 

the available (multiple) sets of 

RNP minimums are listed with the 

lowest set shown first; remaining 

sets shown in ascending order, 

based on the RNP value.

Figure 4-15. RNAV RNP approach procedure with curved flight tracks.
4-29

NC-2, 18 NO

V 2010 to 16 DEC 2010

NC-2, 18 NO

V 2010 to 16 DEC 2010

NOT FOR NAVIGATION

Figure 4-16. North Platte Regional (KLBF), North Platte, Nebraska, RNAV (GPS) RWY 30.
4-30

To attain the benefits of RNP approach procedures, a key 

component is curved flight tracks. Constant radius turns 

around a fix are called “radius-to-fix legs (RF legs).” These 

turns, which are encoded into the navigation database, 

allow the aircraft to avoid critical areas of terrain or 

conflicting airspace while preserving positional accuracy 

by maintaining precise, positive course guidance along 

the curved track. The introduction of RF legs into the 

design of terminal RNAV procedures results in improved 

use of airspace and allows procedures to be developed to 

and from runways that are otherwise limited to traditional 

linear flight paths or, in some cases, not served by an IFR 

procedure at all. Navigation systems with RF capability 

are a prerequisite to flying a procedure that includes an 

RF leg. Refer to the notes box of the pilot briefing portion 

of the approach chart in Figure 4-15.

In the United States, all RNP procedures are in the category 

of RNP AR. Operators who seek to take advantage of 

RNP approach procedures must meet the special RNP 

requirements outlined in FAA AC 90-101, Approval 

Guidance for RNP Procedures with Special Aircraft and 

Aircrew Authorization Required (SAAAR). Currently, most 

new transport category airplanes receive an airworthiness 

approval for RNP operations. However, differences can exist 

in the level of precision that each system is qualified to 

meet. Each individual operator is responsible for obtaining 

the necessary approval and authorization to use these 

instrument flight procedures with navigation databases. 

RNAV Approach Authorization 

Like any other authorization given to air carriers and Part 91 

operators, the authorization to use VNAV on a conventional 

non-precision approach, RNAV approaches, or LNAV/VNAV 

approaches is found in that operator’s OpSpecs, AFM, or 

other FAA-approved documents. There are many different 

levels of authorizations when it comes to the use of RNAV 

approach systems. The type of equipment installed in the 

aircraft, the redundancy of that equipment, its operational 

status, the level of flight crew training, and the level of the 

operator’s FAA authorization are all factors that can affect 

a pilot’s ability to use VNAV information on an approach.

Because most Part 121, 125, 135, and 91 flight departments 

include RNAV approach information in their pilot training 

programs, a flight crew considering an approach to 

North Platte, Nebraska, using the RNAV (GPS) RWY 30 

approach shown in Figure 4-16, would already know which 

minimums they were authorized to use. The company’s 

OpSpecs, FOM, and the AFM for the pilot’s aircraft would 

dictate the specific operational conditions and procedures 

by which this type of approach could be flown.

There are several items of note that are specific to this type 

of approach that should be considered and briefed. One 

is the terminal arrival area (TAA) that is displayed in the 

approach planview. TAAs, discussed later in this chapter, 

depict the boundaries of specific arrival areas, and the 

MIA for those areas. The TAAs should be included in an 

IAP briefing in the same manner as any other IFR transition 

altitude. It is also important to note that the altitudes listed 

in the TAAs should be referenced in place of the MSAs on 

the approach chart for use in emergency situations.

In addition to the obvious differences contained in the 

planview of Figure 4-16, RNAV (GPS) approach procedure 

example, pilots should be aware of the issues related to 

Baro- VNAV and RNP . The notes section of the procedure 

in the example contains restrictions relating to these topics.

RNP values for each individual leg of the procedure, 

defined by the procedure design criteria for containment 

purposes, are encoded into the aircraft’s navigation 

database. Applicable landing minimums are shown in 

a normal manner along with the associated RNP value 

in the landing minimums section. When more than one 

set of RNP landing minimums is available and an aircrew 

is able to achieve lower RNP through approved means, 

the available (multiple) sets of RNP minimums are listed 

with the lowest set shown first; remaining sets shown in 

ascending order, based on the RNP value. On this particular 

procedure, lateral and vertical course guidance from the DA 

to the Runway Waypoint [Landing Threshold Point (LTP)] 

is provided by the aircraft’s FMS and onboard navigation 

database; however, any continued flight beyond and 

below the DA to the landing threshold is to be conducted 

under VMC.

RNP required sensors, FMS capabilities, and relevant 

procedure notes are included in the Pilot Briefing 

Information procedure notes section. [Figure 4-15] RNP 

AR requirements are highlighted in large, bold print. 

RNP procedures are sequenced in the same manner as 

RNAV (GPS) procedures. Procedure title “RNAV” includes 

parenthetical “(RNP)” terminology. RF legs can be used in 

any segment of the procedure (transition, intermediate, 

final, or missed approach). RF leg turn directions (left or 

right) are not noted in the planview because the graphic 

depiction of the flight tracks is intuitive. Likewise, the arc 

center points, arc radius, and associated RF leg performance 

limits, such as bank angles and speeds are not depicted 

because these aircraft performance characteristics are 

encoded in the navigation database. RNP values for each 

individual leg of the procedure, defined by the procedure 

design criteria for containment purposes, are encoded 

into the aircraft's navigation database. Applicable landing 

minimums are shown in a normal manner along with the 

associated RNP value in the landing minimums section. 

When more than one set of RNP landing minimums is 
4-31

Figure 4-18. Explanation of Minima. 

Figure 4-17. Example of LNAV and Circling Minima lower than LNAV/VNAV 

DA. Harrisburg International RNAV (GPS) Runway 13.

available and an aircrew is able to achieve lower RNP 

through approved means, the available (multiple) sets of 

RNP minimums are listed with the lowest set shown first; 

remaining sets shown in ascending order, based on the 

RNP value. On this particular procedure, lateral and vertical 

course guidance from the DA to the Runway Waypoint (LTP) 

is provided by the aircraft’s FMS and onboard navigation 

database; however, any continued flight below the DA 

to the landing threshold is to be conducted under VMC. 

[Figure 4-15]

Baro-VNAV

Baro-VNAV is an RNAV system function that uses barometric 

altitude information from the aircraft’s altimeter to 

compute and present a vertical guidance path to the pilot. 

The specified vertical path is computed as a geometric 

path, typically computed between two waypoints or 

an angle based computation from a single waypoint. 

Operational approval must also be obtained for Baro−

VNAV systems to operate to the LNAV/VNAV minimums. 

Baro−VNAV may not be authorized on some approaches 

due to other factors, such as no local altimeter source being 

available. Baro−VNAV is not authorized on LPV procedures.

Hot and Cold Temperature Limitations

A minimum and maximum temperature limitation is 

published on procedures that authorize Baro−VNAV 

operation. These temperatures represent the airport 

temperature above or below which Baro−VNAV is not 

authorized to LNAV/VNAV minimums unless temperature 

compensation can be accomplished. As an example, the 

limitation will read, uncompensated Baro−VNAV NA below 

−8 °C (−18 °F) or above 47 °C (117 °F). This information will 

be found in the upper left hand box of the pilot briefing. 

When the temperature is above the high temperature 

or below the low temperature limit, Baro−VNAV may be 

used to provide a stabilized descent to the LNAV MDA; 

however, extra caution should be used in the visual 

segment to ensure a vertical correction is not required. If 

the VGSI is aligned with the published glide path, and the 

aircraft instruments indicate on glide path, an above or 

below glide path indication on the VGSI may indicate that 

temperature error is causing deviations to the glide path. 

These deviations should be considered if the approach is 

continued below the MDA.

Many systems which apply Baro−VNAV temperature 

compensation only correct for cold temperature. In this 

case, the high temperature limitation still applies. Also, 

temperature compensation may require activation by 

maintenance personnel during installation in order to be 

functional, even though the system has the feature. Some 

systems may have a temperature correction capability, 

but correct the Baro−altimeter all the time, rather than 

just on the final, which would create conflicts with other 

aircraft if the feature were activated. Pilots should be 

aware of compensation capabilities of the system prior to 

disregarding the temperature limitations. The information 

can be seen in the notes section in Figure 4-16.

For the RNAV (GPS) RWY 30 approach, the note “DME/ 

DME RNP-0.3 NA” prohibits aircraft that use only DME/

DME sensors for RNAV from conducting the approach. 

[Figure 4-16]

Because these procedures can be flown with an approach 

approved RNP system and “RNP” is not sensor specific, it 

was necessary to add this note to make it clear that those 

aircraft deriving RNP 0.3 using DME/DME only are not 

authorized to conduct the procedure.

The least accurate sensor authorized for RNP navigation 

is DME/DME. The necessary DME NAVAID ground 

infrastructure may or may not be available at the airport of 

intended landing. The procedure designer has a computer 

program for determining the usability of DME based on 

geometry and coverage. Where FAA flight inspection 

successfully determines that the coverage and accuracy of 

DME facilities support RNP, and that the DME signal meets 

inspection tolerances, although there are none currently 

published, the note “DME/DME RNP 0.3 Authorized” would 
4-32

EC-3, 18 NOV 2010 to 16 DEC 2010

EC-3, 18 NOV 2010 to 16 DEC 2010

EC-3, 18 NOV 2010 to 16 DEC 2010

EC-3, 18 NOV 2010 to 16 DEC 2010

NOT FOR NAVIGATION

NOT FOR NAVIGATION

Airport sketch

Figure 4-19. Airport sketch and diagram for Chicago O'Hare International.
4-33

be charted. Where DME facility availability is a factor, the 

note would read, “DME/DME RNP 0.3 Authorized; ABC and 

XYZ required,” meaning that ABC and XYZ DME facilities are 

required to assure RNP 0.3.

LNAV, LNAV/VNAV and Circling Minimums

There are some RNAV procedures with lower non-precision 

LNAV minimums [Figure 4-17] than vertically-guided 

LNAV/VNAV minimums. Circling procedures found on 

the same approach plate may also have lower minimums 

than the vertically-guided LNAV/VNAV procedure. Each 

RNAV procedure is evaluated independently and different 

approach segments have differing required obstacle 

clearance (ROC) values, obstacle evaluation area (OEA) 

dimensions and final segment types. Figure 4-18 explains 

the differences.

Airport/Runway Information

Another important piece of a thorough approach briefing 

is the discussion of the airport and runway environment. 

A detailed examination of the runway length (this must 

include the A/FD for the landing distance available), the 

intended turnoff taxiway, and the route of taxi to the 

parking area, are all important briefing items. In addition, 

runway conditions should be discussed. The effect on the 

aircraft’s performance must be considered if the runway 

is contaminated.

FAA approach charts include a runway sketch on each 

approach chart to make important airport information 

easily accessible to pilots. In addition, at airports that have 

complex runway/taxiway configurations, a separate fullpage airport diagram is published.

The airport diagram also includes the latitude/longitude 

information required for initial programming of FMS 

equipment. The included latitude/longitude grid shows the 

specific location of each parking area on the airport surface 

for use in initializing FMS. Figure 4-19 shows the airport 

sketch and diagram for Chicago-O’Hare International 

Airport (KORD).

Pilots making approaches to airports that have this type of 

complex runway and taxiway configuration must ensure 

that they are familiar with the airport diagram prior to 

initiating an instrument approach. A combination of poor 

weather, high traffic volume, and high ground controller 

workload makes the pilot’s job on the ground every bit as 

critical as the one just performed in the air.

Instrument Approach Procedure (IAP) 

Briefing

A thorough instrument approach briefing greatly increases 

the likelihood of a successful instrument approach. Most 

Part 121, 125, and 135 operators designate specific items 

to be included in an IAP briefing, as well as the order in 

which those items are briefed.

Before an IAP briefing can begin, flight crews must decide 

which procedure is most likely to be flown from the 

information that is available to them. Most often, when 

the flight is being conducted into an airport that has 

ATIS information, the ATIS provides the pilots with the 

approaches that are in use. If more than one approach 

is in use, the flight crew may have to make an educated 

guess as to which approach will be issued to them based 

on the weather, direction of their arrival into the area, any 

published airport NOTAMs, and previous contact with the 

approach control facility. Aircrews can query ATC as to 

which approach is to be expected from the controller. Pilots 

may request specific approaches to meet the individual 

needs of their equipment or regulatory restrictions at any 

time and ATC will, in most cases, be able to accommodate 

those requests, providing that workload and traffic permit.

If the flight is operating into an airport without a control 

tower, the flight crew is occasionally given the choice of any 

available instrument approach at the field. In these cases, 

the flight crew must choose an appropriate approach based 

on the expected weather, aircraft performance, direction 

of arrival, airport NOTAMs, and previous experience at the 

airport.

Navigation and Communication Radios 

Once the anticipated approach and runway have been 

selected, each crewmember sets up their side of the flight 

deck. The pilots use information gathered from ATIS, 

dispatch (if available), ATC, the specific approach chart 

for the approach selected, and any other sources that are 

available. Company regulations dictate how certain things 

are set up and others are left up to pilot technique. In 

general, the techniques used at a specific most companies 

are similar. This section addresses two-pilot operations. 

During single-pilot IFR flights, the same items must be set 

up and the pilot should still do an approach briefing to verify 

that everything is set up correctly.

The number of items that can be set up ahead of time 

depends on the level of automation of the aircraft and the 

avionics available. In a conventional flight deck, the only 

things that can be set up, in general, are the airspeed bugs 

(based on performance calculations), altimeter bug (to DA, 

DH, or MDA), go around thrust/power setting, the radio 

altimeter bug (if installed and needed for the approach), 

and the navigation/communication radios (if a standby 

frequency selector is available). The standby side of the PF 
4-34

NE-3, 18 NO

V 2010 to 16 DEC 2010

NE-3, 18 NO

V 2010 to 16 DEC 2010

NOT FOR NAVIGATION

Figure 4-20. Example approaches using autopilot.
4-35

navigation radio should be set to the primary NAVAID for 

the approach and the PM navigation radio standby selector 

should be set to any other NAVAIDs that are required or 

available, and as dictated by company procedures, to 

add to the overall situational awareness of the crew. The 

ADF should also be tuned to an appropriate frequency 

as required by the approach, or as selected by the crew. 

Aircrews should, as much as possible, set up the instruments 

for best success in the event of a vacuum or electrical failure. 

For example, if the aircraft will only display Nav 1 on battery 

or emergency power, aircrews should ensure that Nav 1 is 

configured to the primary NAVAID for the final approach 

to be flown.

Flight Management System (FMS) 

In addition to the items that are available on a conventional 

flight deck aircraft, glass flight deck aircraft, as well as 

aircraft with an approved RNAV (GPS) system, usually 

give the crew the ability to set the final approach course 

for the approach selected and many other options to 

increase situational awareness. Crews of FMS equipped 

aircraft have many options available as far as setting up 

the flight management computer (FMC), depending on 

the type of approach and company procedures. The PF 

usually programs the FMC for the approach and the PM 

verifies the information. A menu of available approaches 

is usually available to select from based on the destination 

airport programmed at the beginning of the flight or a new 

destination selected while en route.

The amount of information provided for the approach 

varies from aircraft to aircraft, but the crew can make 

modifications if something is not pre-programmed into the 

computer, such as adding a MAP or even building an entire 

approach for situational awareness purposes only. The PF 

can also program a VNAV profile for the descent and LNAV 

for segments that were not programmed during preflight, 

such as a standard terminal arrival route (STAR) or expected 

route to the planned approach. Any crossing restrictions 

for the STAR might need to be programmed as well. The 

most common crossing restrictions, whether mandatory 

or “to be expected,” are usually automatically programmed 

when the STAR is selected, but can be changed by ATC at 

any time. Other items that need to be set up are dictated 

by aircraft-specific procedures, such as autopilot, autothrottles, auto-brakes, pressurization system, fuel system, 

seat belt signs, anti-icing/ deicing equipment, and igniters. 

Autopilot Modes 

In general, an autopilot can be used to fly approaches even 

if the FMC is inoperative (refer to the specific airplane’s 

minimum equipment list (MEL) to determine authorization 

for operating with the FMC inoperative). Whether or not the 

FMC is available, use of the autopilot should be discussed 

during the approach briefing, especially regarding the use 

of the altitude pre-selector and auto-throttles, if equipped. 

The AFM for the specific airplane outlines procedures and 

limitations required for the use of the autopilot during an 

instrument approach in that aircraft.

There are just as many different autopilot modes to climb 

or descend the airplane, as there are terms for these modes. 

Some examples are level change (LVL CHG), vertical speed 

(V/S), VNAV, and takeoff/go around (TO/GA). The pilot 

controls the airplane through the autopilot by selecting 

pitch modes and/or roll modes, as well as the associated 

auto-throttle modes. This panel, sometimes called a mode 

control panel, is normally accessible to both pilots. Most 

aircraft with sophisticated auto-flight systems and autothrottles have the capability to select modes that climb 

the airplane with maximum climb thrust and descend the 

airplane with the throttles at idle (LVL CHG, flight level 

change (FL CHG), and manage level). They also have the 

capability to capture, or level off at pre-selected altitudes, 

as well as track a LOC and glideslope (G/S) or a VOR course. 

If the airplane is RNAV-equipped, the autopilot also tracks 

the RNAV- generated course. Most of these modes are 

used at some point during an instrument approach using 

the autopilot. Additionally, these modes can be used to 

provide flight director (FD) guidance to the pilot while 

hand-flying the aircraft.

For the purposes of this precision approach example, the 

auto-throttles are engaged when the autopilot is engaged 

and specific airspeed and configuration changes are not 

discussed. The PF controls airspeed with the speed selector 

on the mode control panel and calls for flaps and landing 

gear as needed, which the PM selects. The example in 

Figure 4-20 begins with the airplane 5 NM northwest of 

KNUCK at 4,500 feet with the autopilot engaged, and the 

flight has been cleared to track the Rwy 12 LOC inbound. 

The current roll mode is LOC with the PF’s NAV radio tuned 

to the LOC frequency of 109.3; and the current pitch mode 

is altitude hold (ALT HOLD). Approach control clears the 

airplane for the approach. The PF makes no immediate 

change to the autopilot mode to prevent the aircraft from 

capturing a false glideslope; but the PM resets the altitude 

selector to 1,700 feet. The aircraft remains level because 

the pitch mode remains in ALT HOLD until another pitch 

mode is selected. Upon reaching KNUCK, the PF selects 

LVL CHG as the pitch mode. The auto-throttles retard to 

idle as the airplane begins a descent. Approaching 1,700 

feet, the pitch mode automatically changes to altitude 

acquire (ALT ACQ) then to ALT HOLD as the airplane levels 

at 1,700 feet. In addition to slowing the airplane and calling 

for configuration changes, the PF selects approach mode 
4-36

27

Runway

Runway

200 feet Not to scale

20:1

34:1

10,000 feet

Figure 4-21. Determination of visibility minimums.

(APP). The roll mode continues to track the LOC and the 

pitch mode remains in ALT HOLD; however, the G/S mode 

arms. Selecting APP once the aircraft has leveled at the 

FAF altitude is a suggested technique to ensure that the 

airplane captures the glideslope from below and that a 

false glideslope is not being tracked.

The PF should have the aircraft fully configured for landing 

before intercepting the glideslope to ensure a stabilized 

approach. As the airplane intercepts the glideslope 

the pitch mode changes to G/S. Once the glideslope is 

captured by the autopilot, the PM can select the missed 

approach altitude in the altitude pre-selector, as requested 

by the PF. The airplane continues to track the glideslope. 

The minimum altitude at which the PF is authorized to 

disconnect the autopilot is airplane specific. For example, 

50 feet below DA, DH, or MDA but not less than 50 feet AGL. 

The PF can disconnect the autopilot at any time prior to 

reaching this altitude during a CAT I approach. The initial 

missed approach is normally hand flown with FD guidance 

unless both autopilots are engaged for auto-land during a 

CAT II or III approach.

The differences when flying the underlying non-precision 

approach begin when the aircraft has leveled off at 1,700 

feet. Once ALT HOLD is annunciated, the MDA is selected 

by the PM as requested by the PF. It is extremely important 

for both pilots to be absolutely sure that the correct altitude 

is selected for the MDA so that the airplane does not 

inadvertently descend below the MDA. For aircraft that the 

altitude pre-selector can only select 100 foot increments, 

the MDA for this approach must be set at 700 feet instead 

of 660 feet. 

Vertical speed mode is used from the FAF inbound to allow 

for more precise control of the descent. If the pilots had 

not selected the MDA in the altitude pre-selector window, 

the PF would not be able to input a V/S and the airplane 

would remain level. The autopilot mode changes from 

ALT ACQ to ALT HOLD as the airplane levels at 700 feet. 

Once ALT HOLD is annunciated, the PF calls for the missed 

approach altitude of 5,000 feet to be selected in the altitude 

pre-selector window. This step is very important because 

accurate FD guidance is not available to the PF during a 

missed approach if the MDA is left in the window.

NOTE: See “Maximum Acceptable Descent Rates” under the 

heading “Descent Rates and Glide paths for Non-precision 

Approaches.”

Descents

Stabilized Approach 

In IMC, you must continuously evaluate instrument 

information throughout an approach to properly maneuver 

the aircraft or monitor autopilot performance and to decide 

on the proper course of action at the decision point (DA, 

DH, or MAP). Significant speed and configuration changes 

during an approach can seriously degrade situational 

awareness and complicate the decision of the proper action 

to take at the decision point. The swept wing handling 

characteristics at low airspeeds and slow engine response 

of many turbojets further complicate pilot tasks during 

approach and landing operations. You must begin to form 

a decision concerning the probable success of an approach 

before reaching the decision point. Your decision-making 

process requires you to be able to determine displacements 

from the course or glidepath centerline, to mentally project 

the aircraft’s three-dimensional flight path by referring 

to flight instruments, and then apply control inputs as 

necessary to achieve and maintain the desired approach 

path. This process is simplified by maintaining a constant 

approach speed, descent rate, vertical flight path, and 

configuration during the final stages of an approach. This 

is referred to as the stabilized approach concept. 

A stabilized approach is essential for safe turbojet operations 

and commercial turbojet operators must establish and 

use procedures that result in stabilized approaches. A 

stabilized approach is also strongly recommended for 

propeller-driven airplanes and helicopters. You should limit 

configuration changes at low altitudes to those changes 

that can be easily accommodated without adversely 

affecting your workload. For turbojets, the airplane must 

be in an approved configuration for landing or circling, 

if appropriate, with the engines spooled up, and on the 

correct speed and flight path with a descent rate of less 

than 1,000 feet per minute (fpm) before descending below 

the following minimum stabilized approach heights: 

•	 For allstraight-in instrument approaches,to include

contact approaches in IFR weather conditions, the 
4-37

EC 2010 ot 13 JAN 2011

SE-1, 16 DEC 2010 to 13 JA

NOT FOR NAVIGATION

Figure 4-22. RNAV approach Fort Campbell, Kentucky.

approach must be stabilized before descending 

below 1,000 feet above the airport or TDZE.

•	 For visual approaches and straight-in instrument

approaches in VFR weather conditions, the approach 

must be stabilized before descending below 500 feet 

above the airport elevation.

•	 For the final segment of a circling approach

maneuver, the approach must be stabilized 500 feet 

above the airport elevation or at the MDA, whichever 

is lower. These conditions must be maintained 

throughout the approach until touchdown for the 

approach to be considered a stabilized approach. 

This also helps you to recognize a wind shear 

situation should abnormal indications exist during 

the approach.

Descent Rates and Glidepaths for Nonprecision 

Approaches 

Maximum Acceptable Descent Rates

Operational experience and research have shown that a 

descent rate of greater than approximately 1,000 fpm is 

unacceptable during the final stages of an approach (below 

1,000 feet AGL). This is due to a human perceptual limitation 

that is independent of the type of airplane or helicopter. 

Therefore, the operational practices and techniques must 

ensure that descent rates greater than 1,000 fpm are not 

permitted in either the instrument or visual portions of an 

approach and landing operation.

For short runways, arriving at the MDA at the MAP when 

the MAP is located at the threshold may require a missed 

approach for some airplanes. For non-precision approaches, 

a descent rate should be used that ensures the airplane 

reaches the MDA at a distance from the threshold that 

allows landing in the TDZ. On many IAPs, this distance 

is annotated by a VDP. To determine the required rate of 

descent, subtract the TDZE from the FAF altitude and divide 

this by the time inbound. For example, if the FAF altitude 

is 2,000 feet MSL, the TDZE is 400 feet MSL and the time 

inbound is 2 minutes, an 800 fpm rate of descent should 

be used.

To verify the airplane is on an approximate three degree 

glidepath, use a calculation of 300 feet to 1 NM. The 

glidepath height above TDZE is calculated by multiplying 

the NM distance from the threshold by 300. For example, 

at 10 NM the aircraft should be 3,000 feet above the TDZE, 
4-38

91.175 TAKEOFF AND LANDING UNDER IFR

 (c) Operation below DA/ DH or MDA. Except as provided in paragraph (l) of this section, where a DA/DH or MDA is 

 applicable, no pilot may operate an aircraft, except a military aircraft of the United States, below the authorized MDA or 

 continue an approach below the authorized DA/DH unless—

 (1) The aircraft is continuously in a position from which a descent to a landing on the intended runway can be made at 

 a normal rate of descent using normal maneuvers, and for operations conducted under part 121 or part 135 unless 

 that descent rate will allow touchdown to occur within the touchdown zone of the runway of intended landing;

 (2) The flight visibility is not less than the visibility prescribed in the standard instrument approach being used; and

 (3) Except for a Category II or Category III approach where any necessary visual reference requirements are specified 

 by the Administrator, at least one of the following visual references for the intended runway is distinctly visible and 

 identifiable to the pilot:

 (i) The approach light system, except that the pilot may not descend below 100 feet above the touchdown zone 

 elevation using the approach lights as a reference unless the red terminating bars or the red side row bars are 

 also distinctly visible and identifiable.

 (ii) The threshold.

 (iii) The threshold markings.

 (iv) The threshold lights.

 (v) The runway end identifier lights.

 (vi) The visual approach slope indicator.

 (vii) The touchdown zone or touchdown zone markings.

 (viii) The touchdown zone lights.

 (ix) The runway or runway markings.

 (x) The runway lights.

 (l) Approach to straight-in landing operations below DH, or MDA using an enhanced flight vision system (EFVS). 

 For straight-in instrument approach procedures other than Category II or Category III, no pilot operating under this section 

 or §§121.651, 125.381, and 135.225 of this chapter may operate an aircraft at any airport below the authorized MDA or 

 continue an approach below the authorized DH and land unless—

 (1) The aircraft is continuously in a position from which a descent to a landing on the intended runway can be made at a 

 normal rate of descent using normal maneuvers, and, for operations conducted under part 121 or part 135 of this 

 chapter, the descent rate will allow touchdown to occur within the touchdown zone of the runway of intended landing;

 (2) The pilot determines that the enhanced flight visibility observed by use of a certified enhanced flight vision system is 

 not less than the visibility prescribed in the standard instrument approach procedure being used;

 (3) The following visual references for the intended runway are distinctly visible and identifiable to the pilot using the 

 enhanced flight vision system:

 (i) The approach light system (if installed); or

 (ii) The following visual references in both paragraphs (l)(3)(ii)(A) and (B) of this section:

 (A) The runway threshold, identified by at least one of the following:

 ( 1 ) The beginning of the runway landing surface;

 ( 2 ) The threshold lights; or

 ( 3 ) The runway end identifier lights.

 (B) The touchdown zone, identified by at least one of the following:

 ( 1 ) The runway touchdown zone landing surface;

 ( 2 ) The touchdown zone lights;

 ( 3 ) The touchdown zone markings; or

 ( 4 ) The runway lights.

 (4) At 100 feet above the touchdown zone elevation of the runway of intended landing and below that altitude, the flight 

 visibility must be sufficient for the following to be distinctly visible and identifiable to the pilot without reliance on the 

 enhanced flight vision system to continue to a landing:

 (i) The lights or markings of the threshold; or

 (ii) The lights or markings of the touchdown zone;

 (5) The pilot(s) is qualified to use an EFVS as follows—

 (i) For parts 119 and 125 certificate holders, the applicable training, testing and qualification provisions of parts 

 121, 125, and 135 of this chapter;

 (ii) For foreign persons, in accordance with the requirements of the civil aviation authority of the State of the 

 operator; or

 (iii) For persons conducting any other operation, in accordance with the applicable currency and proficiency 

 requirements of part 61 of this chapter;

91.175 TAKEOFF AND LANDING UNDER IFR

Figure 4-23. Takeoff and landing under IFR.
4-39

at 5 NM the aircraft should be 1,500 feet above the TDZE, 

at 2 NM the aircraft should be 600 feet above the TDZE, 

and at 1.5 NM the aircraft should be 450 feet above the 

TDZE until a safe landing can be made. Using the example 

in the previous text, the aircraft should arrive at the MDA 

(800 feet MSL) approximately 1.3 NM from the threshold 

and in a position to land within the TDZ. Techniques for 

deriving a 300-to-1 glide path include using DME, distance 

advisories provided by radar-equipped control towers, 

RNAV (exclusive of Omega navigation systems), GPS, dead 

reckoning, and pilotage when familiar features on the 

approach course are visible. The runway threshold should 

be crossed at a nominal height of 50 feet above the TDZE.

Transition to a Visual Approach 

The transition from instrument flight to visual flight during 

an instrument approach can be very challenging, especially 

during low visibility operations. Aircrews should use caution 

when transitioning to a visual approach at times of shallow 

fog. Adequate visibility may not exist to allow flaring of 

the aircraft. Aircrews must always be prepared to execute 

a missed approach/go-around. Additionally, single-pilot 

operations make the transition even more challenging. 

Approaches with vertical guidance add to the safety of 

the transition to visual because the approach is already 

stabilized upon visually acquiring the required references 

for the runway. 100 to 200 feet prior to reaching the DA, 

DH, or MDA, most of the PM’s attention should be outside 

of the aircraft in order to visually acquire at least one visual 

reference for the runway, as required by the regulations. 

The PF should stay focused on the instruments until the 

PM calls out any visual aids that can be seen, or states 

“runway in sight.” The PF should then begin the transition 

to visual flight. It is common practice for the PM to call out 

the V/S during the transition to confirm to the PF that the 

instruments are being monitored, thus allowing more of 

the PF’s attention to be focused on the visual portion of the 

approach and landing. Any deviations from the stabilized 

approach criteria should also be announced by the PM.

Single-pilot operations can be much more challenging 

because the pilot must continue to fly by the instruments 

while attempting to acquire a visual reference for the 

runway. While it is important for both pilots of a two-pilot 

aircraft to divide their attention between the instruments 

and visual references, it is even more critical for the 

single- pilot operation. The flight visibility must also be 

at least the visibility minimum stated on the instrument 

approach chart, or as required by regulations. CAT II and III 

approaches have specific requirements that may differ from 

CAT I precision or non-precision approach requirements 

regarding transition to visual and landing. This information 

can be found in the operator’s OpSpecs or FOM.

The visibility published on an approach chart is dependent 

on many variables, including the height above touchdown 

for straight-in approaches or height above airport elevation 

for circling approaches. Other factors include the approach 

light system coverage, and type of approach procedure, 

such as precision, non-precision, circling or straight-in. 

Another factor determining the minimum visibility is the 

penetration of the 34:1 and 20:1 surfaces. These surfaces 

are inclined planes that begin 200 feet out from the runway 

and extend outward to the DA point (for approaches with 

vertical guidance), the VDP location (for non-precision 

approaches) and 10,000 feet for an evaluation to a circling 

runway. If there is a penetration of the 34:1 surface, the 

published visibility can be no lower than three-fourths SM. 

If there is penetration of the 20:1 surface, the published 

visibility can be no lower than 1 SM with a note prohibiting 

approaches to the affected runway at night (both straightin and circling). [Figure 4-21 ] Circling may be permitted 

at night if penetrating obstacles are marked and lighted. 

If the penetrating obstacles are not marked and lighted, 

a note is published that night circling is “Not Authorized.” 

Pilots should be aware of these penetrating obstacles 

when entering the visual and/or circling segments of an 

approach and take adequate precautions to avoid them. 

For RNAV approaches only, the presence of a grey shaded 

line from the MDA to the runway symbol in the profile view 

is an indication that the visual segment below the MDA is 

clear of obstructions on the 34:1 slope. Absence of the gray 

shaded area indicates the 34:1 OCS is not free of obstructions. 

[Figure 4-22] 

Missed Approach 

Many reasons exist for executing a missed approach. The 

primary reasons, of course, are that the required flight 

visibility prescribed in the IAP being used does not exist 

when natural vision is used under 14 CFR Part 91, section 

91.175(c), the required enhanced flight visibility is less 

than that prescribed in the IAP when an EFVS is used under 

14 CFR Part 91, section 91.175 (l), or the required visual 

references for the runway cannot be seen upon arrival at 

the DA, DH, or MAP. In addition, according to 14 CFR Part 91, 

the aircraft must continuously be in a position from which a 

descent to a landing on the intended runway can be made 

at a normal rate of descent using normal maneuvers, and 

for operations conducted under Part 121 or 135, unless that 

descent rate allows touchdown to occur within the TDZ of 

the runway of intended landing. [Figure 4-23 ] CAT II and 

III approaches call for different visibility requirements as 

prescribed by the FAA Administrator.

Prior to initiating an instrument approach procedure, 

the pilot should assess the actions to be taken in the 

event of a balked (rejected) landing beyond the missed 
4-40

SE-3, 18 NO

V 2010 ot 16 DEC 2010

SE-3, 18 NO

V 2010 to 16 DEC 2010

NOT FOR NAVIGATION

Figure 4-24. Orlando Executive Airport, Orlando, Florida, ILS RWY 7.
4-41

SC-2, 18 NO

V 2010 to 16 DEC 2010

SC-2, 18 NO

V 2010 to 16 DEC 2010

NOT FOR NAVIGATION

Figure 4-25. Missed approach procedures for Dallas-Fort Worth International (DFW).
4-42

SW-3, 18 NO

V 2010 to 16 DEC 2010

SW-3, 18 NO

V 2010 to 16 DEC 2010

010 to 16 DEC 2010

SW-3, 18 NO

V 2010 t

NOT FOR NAVIGATION

This NOTE on the ILS RWY 8 chart for the missed approach climb requirement 

applies to all lines of minimums. If you are unable to make the climb rate/gradient, 

you must use the higher minimums on the separately published LOC RWY 8 

chart that meet the standard climb gradient of 200 feet per NM.

Figure 4-26. Missed approach point depiction and steeper than standard climb gradient requirements.

approach point or below the MDA or DA (H) considering 

the anticipated weather conditions and available aircraft 

performance. 14 CFR 91.175(e) authorizes the pilot to 

fly an appropriate missed approach procedure that 

ensures obstruction clearance, but it does not necessarily 

consider separation from other air traffic. The pilot must 

consider other factors such as the aircraft’s geographical 

location with respect to the prescribed missed approach 

point, direction of flight, and/ or the minimum turning 

altitudes in the prescribed missed approach procedure. 

The pilot must also consider aircraft performance, visual 

climb restrictions, charted obstacles, published obstacle 

departure procedure, takeoff visual climb requirements 

as expressed by nonstandard takeoff minima, other 

traffic expected to be in the vicinity, or other factors not 

specifically expressed by the approach procedures.
4-43

SW-3, 10 M

AR 2011 to 07 APR 2011

SW-3, 10 M

AR 2011 to 07 APR 2011

NOT FOR NAVIGATION

Figure 4-27. Two sets of minimums required when a climb gradient greater than 200 FPNM is required.
4-44

ATIS

Weather/terrain

NOTAMS

Approaches in use

Runway conditions

Performance considerations

Feeder route/expected routing to the

planned approach

Traffic

Radar/non-radar environment

Towered/non-towered airport

Straight-in/circling approach

 Airport/city name

 Approach title

 Amendment number and Julian

 date of when last procedural 

 change to the page was made

 Primary/secondary NAVAID 

 frequencies

 

 Final approach course

 Barometric altitude at OM for

 cross-check

 Decision altitude, decision height 

 or minimum descent altitude (DA,

 DH, or MDA)

 Touchdown zone elevation and 

 airport elevation

 Missed approach procedure

 Minimum safe altitude (MSA)

 Applicable notes

 Approach lighting system

 Visual glideslope indicators (VGSI)

 Required visibility (including

 inoperative equipment adjustments)

 Runway length

 Planned runway turnoff and 

 expected taxi route

 Part-time facility

 Airport diagram

 Alternate/Take-off minimums not 

 standard

1

2

3

4

5

6

7

8

18

19

9

10

11

12

13

14

15

16

17

SC-4, 18 NOV 2010 to 16 DEC 2010

SC-4, 18 NOV 2010 to 16 DEC 2010

NOT FOR NAVIGATION

1

1

1

1

2

2

3

4

4

4

4

5

5

5

6

7

8

18

19

8

9

9

10

11

11

12

12

14

15

15

16

17

13

13

Aircraft specific items, such as auto-pilot, auto-brakes, auto-throttles, speed brakes, reverse thrust, etc.

Aircraft specific missed approach considerations/techniques

Additional items/duties pertaining to the situation (CAT II/III [auto-land], inoperative equipment, etc.)

Transfer of flight controls

Communications

Instrument Approach/

Operational Briefing Items

Figure 4-28. Example of approach chart briefing sequence.
4-45

A clearance for an instrument approach procedure 

includes a clearance to fly the published missed approach 

procedure, unless otherwise instructed by ATC. Once 

descent below the DA, DH, or MDA is begun, a missed 

approach must be executed if the required visibility is lost 

or the runway environment is no longer visible, unless the 

loss of sight of the runway is a result of normal banking 

of the aircraft during a circling approach. A MAP is also 

required upon the execution of a rejected landing for any 

reason, such as men and equipment or animals on the 

runway, or if the approach becomes unstabilized and a 

normal landing cannot be performed. After the MAP in 

the visual segment of a non-precision approach, there may 

be hazards when executing a missed approach below the 

MDA. The published missed approach procedure provides 

obstacle clearance only when the missed approach is 

conducted on the missed approach segment from or 

above the missed approach point, and assumes a climb 

rate of 200 FPNM or higher, as published. If the aircraft 

initiates a missed approach at a point other than the 

missed approach point, from below MDA or DA (H), or on 

a circling approach, obstacle clearance is not provided by 

following the published missed approach procedure, nor 

is separation assured from other air traffic in the vicinity.

The missed approach climb is normally executed at the 

MAP. If such a climb is initiated at a higher altitude prior 

to the MAP, pilots must be aware of any published climbaltitude limitations, which must be accounted for when 

commencing an early climb. Figure 4-24 gives an example 

of an altitude restriction that would prevent a climb 

between the FAF and MAP. In this situation, the Orlando 

Executive ILS or LOC RWY 7 approach altitude is restricted 

at the BUVAY 3 DME fix to prevent aircraft from penetrating 

the overlying protected airspace for approach routes into 

Orlando International Airport. If a missed approach is 

initiated before reaching BUVAY, a pilot may be required 

to continue descent to 1,200 feet before proceeding 

to the MAP and executing the missed approach climb 

instructions. In addition to the missed approach notes 

on the chart, the Pilot Briefing Information icons in the 

profile view indicate the initial vertical and lateral missed 

approach guidance.

The missed approach course begins at the MAP and 

continues until the aircraft has reached the designated 

fix and a holding pattern has been entered. [Figure 4-25] 

In these circumstances, ATC normally issues further 

instructions before the aircraft reaches the final fix of 

the missed approach course. It is also common for the 

designated fix to be an IAF so that another approach 

attempt can be made without having to fly from the 

holding fix to an IAF.

In the event a balked (rejected) landing occurs at a position 

other than the published missed approach point, the 

pilot should contact ATC as soon as possible to obtain an 

amended clearance. If unable to contact ATC for any reason, 

the pilot should attempt to re−intercept a published 

segment of the missed approach and comply with route 

and altitude instructions. If unable to contact ATC, and 

in the pilot’s judgment it is no longer appropriate to fly 

the published missed approach procedure, then consider 

either maintaining visual conditions (if possible) and 

reattempt a landing, or a circle−climb over the airport. 

Should a missed approach become necessary when 

operating to an airport that is not served by an operating 

control tower, continuous contact with an air traffic facility 

may not be possible. In this case, the pilot should execute 

the appropriate go−around/missed approach procedure 

without delay and contact ATC when able to do so.

As shown in Figure 4-26 , there are many different ways 

that the MAP can be depicted, depending on the type 

of approach. On all approach charts, it is depicted in the 

profile and plan views by the end of the solid course 

line and the beginning of the dotted missed approach 

course line for the top-line/ lowest published minima. For 

a precision approach, the MAP is the point at which the 

aircraft reaches the DA or DH while on the glideslope. MAPs 

on non-precision approaches can be determined in many 

different ways. If the primary NAVAID is on the airport, and 

either a VOR or NDB approach is being executed, the MAP is 

normally the point at which the aircraft passes the NAVAID.

On some non-precision approaches, the MAP is given 

as a fixed distance with an associated time from the FAF 

to the MAP based on the groundspeed of the aircraft. A 

table on the lower right hand side of the approach chart 

shows the distance in NM from the FAF to the MAP and 

the time it takes at specific groundspeeds, given in 30 

knot increments. Pilots must determine the approximate 

groundspeed and time based on the approach speed and 

true airspeed of their aircraft and the current winds along 

the final approach course. A clock or stopwatch should be 

started at the FAF of an approach requiring this method. 

Many non-precision approaches designate a specific fix 

as the MAP. These can be identified by a course (LOC or 

VOR) and DME, a cross radial from a VOR, or an RNAV (GPS) 

waypoint.

Obstacles or terrain in the missed approach segment 

may require a steeper climb gradient than the standard 

200 FPNM. If a steeper climb gradient is required, a note 

is published on the approach chart plan view with the 

penetration description and examples of the required 

FPM rate of climb for a given groundspeed (future charting 
4-46

Feeder route

FAF

IF

IAF

Initial Intermediate Final Runway Missed 

approach

Re-enter 

En route phase

IAF

IF

FAF Obstacle

Flightpath Map

500 feet

1,000 feet 1,000 feet 250 feet

Project view

Profile view

Plan view

Figure 4-29. Approach segments and obstacle clearance.

uses climb gradient). An alternative is normally charted 

that allows using the standard climb gradient. [Figure 

4-26 ] In this example, if the missed approach climb 

requirements cannot be met for the Burbank ILS RWY 8 

chart, the alternative is to use the LOC RWY 8 that is charted 

separately. The LOC RWY 8, S-8 procedure has a MDA that 

is 400 feet higher than the ILS RWY 8, S-LOC 8 MDA and 

meets the standard climb gradient requirement over the 

terrain. For some approaches a new charting standard is 

requiring two sets of minimums to be published when 

a climb gradient greater than 200 FPNM is required. The 

first set of minimums is the lower of the two, requiring a 

climb gradient greater than 200 FPNM. The second set of 

minimums is higher, but doesn’t require a climb gradient. 

Shown in Figure 4-27 , Barstow-Daggett (KDAG) RNAV 

(GPS) RWY 26 is an example where there are two LPV lines 

of minimums.

Example Approach Briefing 

During an instrument approach briefing, the name of the 

airport and the specific approach procedure should be 

identified to allow other crewmembers the opportunity 

to cross-reference the chart being used for the brief. This 

ensures that pilots intending to conduct an instrument 

approach have collectively reviewed and verified the 

information pertinent to the approach. Figure 4-28 

gives an example of the items to be briefed and their 

sequence. Although the following example is based on 

multi-crew aircraft, the process is also applicable to singlepilot operations. A complete instrument approach and 

operational briefing example follows.

The approach briefing begins with a general discussion of 

the ATIS information, weather, terrain, NOTAMs, approaches 

in use, runway conditions, performance considerations, 

expected route to the final approach course, and the 

traffic situation. As the discussion progresses, the items 

and format of the briefing become more specific. The 

briefing can also be used as a checklist to ensure that 

all items have been set up correctly. Most pilots verbally 

brief the specific MAP so that it is fresh in their minds and 

there is no confusion as to who is doing what during a 

missed approach. Also, it is a very good idea to brief the 

published missed approach even if the tower is most likely 

to give you alternate instructions in the event of a missed 

approach. A typical approach briefing might sound like 

the following example for a flight inbound to the Monroe 

Regional Airport (KMLU):

ATIS: “Monroe Regional Airport Information Bravo, time

2253 Zulu, wind 360 at 10, visibility 1 mile, mist, ceiling 300 

overcast, temperature 4, dew point 3, altimeter 29.73, ILS 

Runway 4 approach in use, landing and departing Runway 

4, advise on initial contact that you have information Bravo.”

PF: “We’re planning an ILS approach to Runway 4 at Monroe
4-47

NC-1, 16 DEC 2010 to 13 JAN 2011

NC-1, 16 DEC 2010 to 13 JAN 2011

NOT FOR NAVIGATION

Figure 4-30. Feeder routes.
4-48

NC-1, 16 DEC 2010 to 13 JAN 2011

NC-1, 16 DEC 2010 to 13 JAN 2011

NOT FOR NAVIGATION

Figure 4-31. Terminal routes.
4-49

2

NM

2

NM 4 NM 4 NM

500

feet

500

feet

1,000

feet

Initial segment

Intermediate

segment 500

feet

500

feet

VORTAC

2

NM

2

NM

4 NM

4 NM

Length

 

The intermediate segment may NOT be less than 

5 NM nor more than 15 NM in length, measured 

along the arc. The OPTIMUM length is 10 NM. 

A distance greater than 10 NM should not be used 

unless an operational requirement justifies the

greater distance.

Width

The total width of an arc intermediate segment is 6 

NM on each side of the arc. For obstacle clearance 

purposes, this width is divided into a primary and a 

secondary area. The primary area extends 4 NM

laterally on each side of the arc segment. The 

secondary areas extend 2 NM laterally on each side 

of the primary area.

Required Obstacle Clearance (ROC)

The ROC is 1,000 feet for the primary initial segment. 

The secondary area ROC starts at the primary ROC 

surface tapering to zero at the edges of the secondary 

area in both initial and intermediate areas. In the 

primary area of the intermediate segment, the ROC is

500 feet.

Figure 4-32. DME arc obstruction clearance.

Regional Airport, page 270, effective date 22 Sep 11 to 20

Oct 11. Localizer frequency is 109.5, SABAR Locator Outer

Marker is 392, Monroe VOR is 117.2, final approach course is

042o. We’ll cross SABAR at 1,483 feet barometric, decision 

altitude is 278 feet barometric, touchdown zone elevation is

78 feet with an airport elevation of 79 feet. MAP is climb 

to 2,000 feet, then climbing right turn to 3,000 feet direct 

Monroe VOR and hold. The MSA is 2,200 feet to the north 

and along our missed approach course, and 3,100 feet to 

the south along the final approach course. ADF or DME 

is required for the approach and the airport has pilot 

controlled lighting when the tower is closed, which does 

not apply to this approach. The runway has a medium 

intensity approach lighting system with runway alignment 

indicator lights and a precision approach path indicator 

(PAPI). We need a half- mile visibility so with one mile we 

should be fine. Runway length is 7,507 feet. I’m planning 

a flaps 30 approach, auto- brakes 2, left turn on Alpha or 

Charlie 1 then Alpha, Golf to the ramp. With a left crosswind, 

the runway should be slightly to the right. I’ll use the 

autopilot until we break out and, after landing, I’ll slow 

the aircraft straight ahead until you say you have control 

and I’ll contact ground once we are clear of the runway. In 

the case of a missed approach, I’ll press TOGA (Take-off/

Go-Around button used on some turbojets), call

‘go-around thrust, flaps 15, positive climb, gear up, set me 

up,’ climb straight ahead to 2,000 feet then climbing right 

turn to 3,000 feet toward Monroe or we’ll follow the tower’s 

instructions. Any questions?”

PM: “I’ll back up the auto-speedbrakes. Other than that, I

don’t have any questions.”

Instrument Approach Procedure 

Segments

An instrument approach may be divided into as many as 

four approach segments: initial, intermediate, final, and 

missed approach. Additionally, feeder routes provide a 

transition from the en route structure to the IAF. FAA Order 

8260.3 (ERPS) criteria provides obstacle clearance for each 

segment of an approach procedure as shown in Figure 4-29. 

Feeder Routes 

By definition, a feeder route is a route depicted on IAP 

charts to designate routes for aircraft to proceed from the 

en route structure to the IAF. [Figure 4-30 ] Feeder routes, 

also referred to as approach transitions, technically are 

not considered approach segments but are an integral 
4-50

Reversal x may 

be specied

Complete in “remain 

within” distance

The 45°/180° procedure turn 

The 80°/260° procedure turn Base turn

Racetrack procedure

Specied time or depicted x 

1 minute

Reversal x may 

be specied

Complete in “remain 

within” distance

1 min 15 sec

-Cat C,D&E

Figure 4-33. Course reversal methods.

part of many IAPs. Although an approach procedure may 

have several feeder routes, pilots normally choose the one 

closest to the en route arrival point. When the IAF is part of 

the en route structure, there may be no need to designate 

additional routes for aircraft to proceed to the IAF.

When a feeder route is designated, the chart provides 

the course or bearing to be flown, the distance, and the 

minimum altitude. En route airway obstacle clearance 

criteria apply to feeder routes, providing 1,000 feet of 

obstacle clearance (2,000 feet in mountainous areas).

Terminal Routes

In cases where the IAF is part of the en route structure 

and feeder routes are not required, a transition or terminal 

route is still needed for aircraft to proceed from the IAF to 

the intermediate fix (IF). These routes are initial approach 

segments because they begin at the IAF. Like feeder routes, 

they are depicted with course, minimum altitude, and 

distance to the IF. Essentially, these routes accomplish the 

same thing as feeder routes but they originate at an IAF, 

whereas feeder routes terminate at an IAF. [Figure 4-31 ]

DME Arcs

DME arcs also provide transitions to the approach course, 

but DME arcs are actually approach segments while feeder 

routes, by definition, are not. When established on a DME 

arc, the aircraft has departed the en route phase and has 

begun the approach and is maneuvering to enter an 

intermediate or final segment of the approach. DME arcs 

may also be used as an intermediate or a final segment, 

although they are extremely rare as final approach 

segments.

An arc may join a course at or before the IF. When joining 

a course at or before the IF, the angle of intersection of the 

arc and the course is designed so it does not exceed 120°. 

When the angle exceeds 90°, a radial that provides at least 2 

NM of lead will be identified to assist in leading the turn on 

to the intermediate course. DME arcs are predicated on DME 

collocated with a facility providing omnidirectional course 

information, such as a VOR. A DME arc cannot be based on 

an ILS or LOC DME source because omnidirectional course 

information is not provided.

The ROC along the arc depends on the approach segment. 

For an initial approach segment, a ROC of 1,000 feet is 

required in the primary area, which extends to 4 NM on 

either side of the arc. For an intermediate segment primary 

area, the ROC is 500 feet. The initial and intermediate 

segment secondary areas extend 2 NM from the primary 

boundary area edge. The ROC starts at the primary area 

boundary edge at 500 feet and tapers to zero feet at the 

secondary area outer edge. [Figure 4-32 ]
4-51

Obstacle

Obstacle

Entry zone

Maneuvering zone

Procedure turn completion altitude

Altitude restricted until completing

departing turn fix outbound

6,000

6,900

7,700

1,000 feet

1,000 feet

Figure 4-34. Procedure turn obstacle clearance.

Course Reversal

Some approach procedures do not permit straight-in 

approaches unless pilots are being radar vectored. In these 

situations, pilots are required to complete a procedure turn 

(PT) or other course reversal, generally within 10 NM of the 

PT fix, to establish the aircraft inbound on the intermediate 

or final approach segment.

If Category E airplanes are using the PT or there is a descent 

gradient problem, the PT distance available can be as much 

as 15 NM. During a procedure turn, a maximum speed of

200 knots indicated airspeed (KIAS) should be observed 

from first crossing the course reversal IAF through the 

procedure turn maneuver to ensure containment within 

the obstruction clearance area. Unless a holding pattern 

or teardrop procedure is published, the point where pilots 

begin the turn and the type and rate of turn are optional. 

If above the procedure turn minimum altitude, pilots may 

begin descent as soon as they cross the IAF outbound.

A procedure turn is the maneuver prescribed to perform 

a course reversal to establish the aircraft inbound on an 

intermediate or final approach course. The procedure turn 

or hold-in-lieu-of procedure turn is a required maneuver 

when it is depicted on the approach chart. However, the 

procedure turn or the hold-in-lieu-of PT is not permitted 

when the symbol “No PT” is depicted on the initial segment 

being flown, when a RADAR VECTOR to the final approach 

course is provided, or when conducting a timed approach 

from a holding fix.
4-52

Initial approach segment

Feeder route

En route fix

IAF

FAF Beginning of intermediate segment

Figure 4-35. Approach without a designated IF.

The altitude prescribed for the procedure turn is a 

minimum altitude until the aircraft is established on the 

inbound course. The maneuver must be completed within 

the distance specified in the profile view. This distance is 

usually 10 miles. This may be reduced to 5 miles where only 

Category A or helicopter aircraft are operated. This distance 

may be increased to as much as 15 miles to accommodate 

high performance aircraft. 

The pilot may elect to use the procedure turn or hold-inlieu- of PT when it is not required by the procedure, but 

must first receive an amended clearance from ATC. When 

ATC is radar vectoring to the final approach course, or to 

the intermediate fix as may occur with RNAV standard 

instrument approach procedures, ATC may specify in 

the approach clearance “CLEARED STRAIGHT-IN (type) 

APPROACH” to ensure that the pilot understands that the 

procedure turn or hold-in- lieu-of PT is not to be flown. If 

the pilot is uncertain whether ATC intends for a procedure 

turn or a straight-in approach to be flown, the pilot will 

immediately request clarification from ATC.

On U.S. Government charts, a barbed arrow indicates the 

maneuvering side of the outbound course on which the 

procedure turn is made. Headings are provided for course 

reversal using the 45° type procedure turn. However, the 

point at which the turn may be commenced and the type 

and rate of turn is left to the discretion of the pilot (limited 

by the charted remain within XX NM distance). Some of the 

options are the 45° procedure turn, the racetrack pattern,

 the teardrop procedure turn, or the 80° procedure turn, or 

the 80° 260° course reversal. Racetrack entries should 

be conducted on the maneuvering side where the majority 

of protected airspace resides. If an entry places the pilot 

on the non-maneuvering side of the PT, correction to 

intercept the outbound course ensures remaining within 

protected airspace.

Some procedure turns are specified by procedural track. 

These turns must be flown exactly as depicted. These 

requirements are necessary to stay within the protected 

airspace and maintain adequate obstacle clearance. [Figure 

4-33] A minimum of 1,000 feet of obstacle clearance is 

provided in the procedure turn primary area. [Figure 4-34] 

In the secondary area, 500 feet of obstacle clearance is 

provided at the inner edge, tapering uniformly to 0 feet 

at the outer edge.

The primary and secondary areas determine obstacle 

clearance in both the entry and maneuvering zones. The 

use of entry and maneuvering zones provides further relief 

from obstacles. The entry zone is established to control the 

obstacle clearance prior to proceeding outbound from the 

procedure turn fix. The maneuvering zone is established 

to control obstacle clearance after proceeding outbound 
4-53

from the procedure turn fix.

Descent to the PT completion altitude from the PT fix 

altitude (when one has been published or assigned by ATC) 

must not begin until crossing over the PT fix or abeam and 

proceeding outbound. Some procedures contain a note in 

the chart profile view that says “Maintain (altitude) or above 

until established outbound for procedure turn.” Newer 

procedures simply depict an “at or above” altitude at the PT 

fix without a chart note. Both are there to ensure required 

obstacle clearance is provided in the procedure turn 

entry zone. Absence of a chart note or specified minimum 

altitude adjacent to the PT fix is an indication that descent 

to the procedure turn altitude can commence immediately 

upon crossing over the PT fix, regardless of the direction 

of flight. This is because the minimum altitudes in the PT 

entry zone and the PT maneuvering zone are the same.

A holding pattern in lieu of procedure turn may be specified 

for course reversal in some procedures. In such cases, the 

holding pattern is established over an intermediate fix or 

a FAF. The holding pattern distance or time specified in the 

profile view must be observed. For a hold-in-lieu-of PT, the 

holding pattern direction must be flown as depicted and 

the specified leg length/timing must not be exceeded. 

Maximum holding airspeed limitations as set forth for all 

holding patterns apply. The holding pattern maneuver is 

completed when the aircraft is established on the inbound 

course after executing the appropriate entry. If cleared for 

the approach prior to returning to the holding fix and the 

aircraft is at the prescribed altitude, additional circuits of 

the holding pattern are not necessary nor expected by ATC. 

If pilots elect to make additional circuits to lose excessive 

altitude or to become better established on course, it is 

their responsibility to so advise ATC upon receipt of their 

approach clearance. Refer to the AIM section 5-4-9 for 

additional information on holding procedures.

Initial Approach Segment 

The purposes of the initial approach segment are to provide 

a method for aligning the aircraft with the intermediate 

or final approach segment and to permit descent during 

the alignment. This is accomplished by using a DME arc, 

a course reversal, such as a procedure turn or holding 

pattern, or by following a terminal route that intersects 

the final approach course. The initial approach segment 

begins at an IAF and usually ends where it joins the 

intermediate approach segment or at an IF. The letters IAF 

on an approach chart indicate the location of an IAF and 

more than one may be available. Course, distance, and 

minimum altitudes are also provided for initial approach 

segments. A given procedure may have several initial 

approach segments. When more than one exists, each joins 

a common intermediate segment, although not necessarily 

at the same location.

Many RNAV approaches make use of a dual-purpose IF/

IAF associated with a hold-in-lieu-PT (HILPT) anchored at 

the Intermediate Fix. The HILPT forms the Initial Approach 

Segment when course reversal is required.

When the PT is required, it is only necessary to enter the 

holding pattern to reverse course. The dual purpose fix 

functions as an IAF in that case. Once the aircraft has 

entered the hold and is returning to the fix on the inbound 

course, the dual-purpose fix becomes an IF, marking the 

beginning of the intermediate segment.

ATC may provide a vector to an IF at an angle of 90 degrees 

or less and specify “Cleared Straight-in (type) Approach”. 

In those cases, the radar vector is providing the initial 

approach segment and the pilot should not fly the PT 

without a clearance from ATC.

Occasionally, a chart may depict an IAF, although there is 

no initial approach segment for the procedure. This usually 

occurs at a point located within the en route structure 

where the intermediate segment begins. In this situation, 

the IAF signals the beginning of the intermediate segment. 

Intermediate Approach Segment 

The intermediate segment is designed primarily to position 

the aircraft for the final descent to the airport. Like the feeder 

route and initial approach segment, the chart depiction of 

the intermediate segment provides course, distance, and 

minimum altitude information.

The intermediate segment, normally aligned within 30° of 

the final approach course, begins at the IF, or intermediate 

point, and ends at the beginning of the final approach 

segment. In some cases, an IF is not shown on an approach 

chart. In this situation, the intermediate segment begins at 

a point where you are proceeding inbound to the FAF, are 

properly aligned with the final approach course, and are 

located within the prescribed distance prior to the FAF. An 

instrument approach that incorporates a procedure turn 

is the most common example of an approach that may 
4-54

not have a charted IF. The intermediate segment in this 

example begins when you intercept the inbound course 

after completing the procedure turn. [Figure 4-35 ]

Final Approach Segment 

The final approach segment for an approach with vertical 

guidance or a precision approach begins where the 

glideslope intercepts the minimum glideslope intercept 

altitude shown on the approach chart. If ATC authorizes 

a lower intercept altitude, the final approach segment 

begins upon glideslope interception at that altitude. For 

a non-precision approach, the final approach segment 

begins either at a designated FAF, which is depicted as a 

cross on the profile view, or at the point where the aircraft 

is established inbound on the final approach course. 

When a FAF is not designated, such as on an approach 

that incorporates an on-airport VOR or NDB, this point 

is typically where the procedure turn intersects the final 

approach course inbound. This point is referred to as the 

final approach point (FAP). The final approach segment 

ends at either the designated MAP or upon landing.

There are three types of procedures based on the final

approach course guidance:

•	 Precision approach (PA)—an instrument approach

based on a navigation system that provides course 

and glidepath deviation information meeting 

precision standards of ICAO Annex 10. For example, 

PAR, ILS, and GLS are precision approaches.

•	 Approach with vertical guidance (APV) —an

instrument approach based on a navigation system 

that is not required to meet the precision approach 

standards of ICAO Annex 10, but provides course 

and glidepath deviation information. For example, 

Baro-VNAV, LDA with glidepath, LNAV/VNAV and LPV 

are APV approaches.

•	 Non-precision approach (NPA)—an instrument

approach based on a navigation system that 

provides course deviation information but no 

glidepath deviation information. For example, VOR, 

TACAN, LNAV, NDB, LOC, and ASR approaches are 

examples of NPA procedures.

Missed Approach Segment 

The missed approach segment begins at the MAP and ends 

at a point or fix where an initial or en route segment begins. 

The actual location of the MAP depends upon the type of 

approach you are flying. For example, during a precision 

or an APV approach, the MAP occurs at the DA or DH on 

the glideslope. For non-precision approaches, the MAP is 

either a fix, NAVAID, or after a specified period of time has 

elapsed after crossing the FAF.

Approach Clearance 

According to FAA Order 7110.65, ATC clearances authorizing 

instrument approaches are issued on the basis that if visual 

contact with the ground is made before the approach is 

completed, the entire approach procedure is followed 

unless the pilot receives approval for a contact approach, is 

cleared for a visual approach, or cancels the IFR flight plan.

Approach clearances are issued based on known traffic. 

The receipt of an approach clearance does not relieve the 

pilot of his or her responsibility to comply with applicable 

parts of the CFRs and notations on instrument approach 

charts, which impose on the pilot the responsibility to 

comply with or act on an instruction, such as “procedure 

not authorized at night.” The name of the approach, as 

published, is used to identify the approach. Approach name 

items within parentheses are not included in approach 

clearance phraseology.

Vectors To Final Approach Course

The approach gate is an imaginary point used within ATC 

as a basis for vectoring aircraft to the final approach course. 

The gate is established along the final approach course one 

mile from the FAF on the side away from the airport and is 

no closer than 5 NM from the landing threshold. Controllers 

are also required to ensure the assigned altitude conforms 

to the following: 

•	 For a precision approach, at an altitude not above

the glideslope/glidepath or below the minimum 

glideslope intercept altitude specified on the 

approach procedure chart.

•	 For a non-precision approach, at an altitude that

allows descent in accordance with the published 

procedure. 

Further, controllers must assign headings that 

intercept the final approach course no closer than 

the following table:

A typical vector to the final approach course and associated

approach clearance is as follows:

“...four miles from LIMA, turn right heading three four zero, 
4-55

SW-1, 16 DEC 2010 to 13 JAN 2011

SW-1, 16 DEC 2010 to 13 JAN 2011

Often visual procedures are not authorized 

at night due to surrounding terrain. NOT FOR NAVIGATION

NAVAID information is for supplemental guidance only.

You are not prohibited from flying otherthan-recommended altitudes as 

operational requirements dictate.

Published weather minimums are based 

on minimum vectoring altitudes rather 

than the recommended altitudes depicted 

on charts.

A CVFP will help you locate key 

landmarks at an unfamiliar airport 

and provide you and ATC with 

common reporting points.

Figure 4-36. Charted visual flight procedures (CVFP).
4-56

maintain two thousand until established on the localizer, 

cleared ILS runway three six approach.”

Other clearance formats may be used to fit individual 

circumstances, but the controller should always assign an 

altitude to maintain until the aircraft is established on a 

segment of a published route or IAP. The altitude assigned 

must guarantee IFR obstruction clearance from the point 

at which the approach clearance is issued until the aircraft 

is established on a published route. 14 CFR Part 91, section

91.175 (j) prohibits a pilot from making a procedure turn 

when vectored to a FAF or course, when conducting a 

timed approach, or when the procedure specifies “NO PT.”

When vectoring aircraft to the final approach course, 

controllers are required to ensure the intercept is at least 

2 NM outside the approach gate. Exceptions include the 

following situations, but do not apply to RNAV aircraft 

being vectored for a GPS or RNAV approach: 

•	 When the reported ceiling is at least 500 feet above

the MVA/MIA and the visibility is at least 3 SM (may 

be a pilot report (PIREP) if no weather is reported for 

the airport), aircraft may be vectored to intercept 

the final approach course closer than 2 NM outside 

the approach gate but no closer than the approach 

gate.

•	 If specifically requested by the pilot, aircraft may

be vectored to intercept the final approach course 

inside the approach gate but no closer than the FAF.

Nonradar Environment 

In the absence of radar vectors, an instrument approach 

begins at an IAF. An aircraft that has been cleared to 

a holding fix that, prior to reaching that fix, is issued a 

clearance for an approach, but not issued a revised routing, 

such as, “proceed direct to...” is expected to proceed via the 

last assigned route, a feeder route if one is published on 

the approach chart, and then to commence the approach 

as published. If, by following the route of flight to the 

holding fix, the aircraft would overfly an IAF or the fix 

associated with the beginning of a feeder route to be used, 

the aircraft is expected to commence the approach using 

the published feeder route to the IAF or from the IAF as 

appropriate. The aircraft would not be expected to overfly 

and return to the IAF or feeder route.

For aircraft operating on unpublished routes, an altitude 

is assigned to maintain until the aircraft is established on 

a segment of a published route or IAP. (Example: “Maintain

2,000 until established on the final approach course 

outbound, cleared VOR/DME runway 12.”) The FAA 

definition of established on course requires the aircraft 

to be established on the route centerline. Generally, the 

controller assigns an altitude compatible with glideslope 

intercept prior to being cleared for the approach.

Types of Approaches

In the NAS, there are approximately 1,105 VOR stations, 916

NDB stations, and 1,194 ILS installations, including 25 LOCtype directional aids (LDAs), 11 simplified directional facilities 

(SDFs), and 235 LOC only facilities. As time progresses, it is 

the intent of the FAA to reduce navigational dependence on 

VOR, NDB, and other ground-based NAVAIDs and, instead, 

to increase the use of satellite-based navigation.

To expedite the use of RNAV procedures for all instrument 

pilots, the FAA has begun an aggressive schedule to 

develop RNAV procedures. As of 2010, the number of 

RNAV/ GPS approaches published in the NAS numbered 

10,212, with additional procedures published every revision 

cycle. While it had originally been the plan of the FAA to 

begin decommissioning VORs, NDBs, and other groundbased NAVAIDs, the overall strategy has been changed to 

incorporate a majority dependence on augmented satellite 

navigation while maintaining a satisfactory backup system. 

This backup system includes retaining all CAT II and III ILS 

facilities and close to one-half of the existing VOR network. 

Each approach is provided obstacle clearance based on 

the Order 8260.3 TERPS design criteria as appropriate for 

the surrounding terrain, obstacles, and NAVAID availability. 

Final approach obstacle clearance is different for every 

type of approach but is guaranteed from the start of the 

final approach segment to the runway (not below the MDA 

for non-precision approaches) or MAP, whichever occurs 

last within the final approach area. It is dependent upon 

the pilot to maintain an appropriate flight path within 

the boundaries of the final approach area and maintain 

obstacle clearance.

There are numerous types of instrument approaches 

available for use in the NAS including RNAV (GPS), ILS, MLS, 

LOC, VOR, NDB, SDF, and radar approaches. Each approach 

has separate and individual design criteria, equipment 

requirements, and system capabilities. 

Visual and Contact Approaches 

To expedite traffic, ATC may clear pilots for a visual 

approach in lieu of the published approach procedure if 

flight conditions permit. Requesting a contact approach 

may be advantageous since it requires less time than 

the published IAP and provides separation from IFR and 

special visual flight rules (SVFR) traffic. A contact or visual 

approach may be used in lieu of conducting a SIAP, and 

both allow the flight to continue as an IFR flight to landing 

while increasing the efficiency of the arrival.
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TAAs do not describe specific routes of flight, but rather describe a 

volume of airspace within which an aircraft proceeds inbound from 

the 30 NM arc boundary toward an appropriate IAF.

Normally, the IF also is designated

an IAF for straight-in (NoPT)

procedures. If a straight-in procedure

cannot be used due to terrain or 

airspace considerations, the IF will

not be designated an IAF. If 

circumstances require a course 

reversal, a holding pattern is 

established at the IF/IAF.

The “Basic T” design ideally aligns the 

procedure with runway centerline, 

with the MAP located at the threshold, 

the FAF 5 NM from the threshold, and

the intermediate fix (IF) 5 NM from the 

FAF.

The “Basic T” usually incorporates 2 

IAFs located 3 to 6 NM on either side

of the final IF/IAF, approximately 90°

to the final approach course. The leg

length or angle of the turn to the intermediate segment may be modified when 

required by obstructions or airspace.

Straight-in

Right base

Left base

Figure 4-37. Terminal arrival area (TAA) design “basic T.”

Visual Approaches

When it is operationally beneficial, ATC may authorize 

pilots to conduct a visual approach to the airport in lieu 

of the published IAP. A pilot, or the controller, can initiate a 

visual approach. Before issuing a visual approach clearance, 

the controller must verify that pilots have the airport, or a 

preceding aircraft that they are to follow, in sight. In 

the event pilots have the airport in sight but do not see 

the aircraft they are to follow, ATC may issue the visual 

approach clearance but maintain responsibility for aircraft 

and wake turbulence separation. Once pilots report the 

aircraft in sight, they assume the responsibilities for their 

own separation and wake turbulence avoidance.
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SC-2, 16 DEC 2010 to 13 JAN 2011

SC-2, 16 DEC 2010 to 13 JAN 2011

EC-1, 16 DEC 2010 to 13 JAN 2011

EC-1, 16 DEC 2010 ot 13 JAN 2011

NOT FOR NAVIGATION

The RNAV (GPS) procedure (KAPF)

features the basic “T” design. Notice 

the left base icon is sectorized in this 

example and the MSA has been 

replaced. This means the TAA 

minimum altitudes specified in the 

plan view can be flown as depicted. 

The other RNAV (GPS) procedures

(KAFW and KOZW) do not incorporate

TAAs for operational reasons. Instead, 

feeder routes have been estblished for 

transitions to the approach. Notice 

MSAs are established for emergency 

use only; terminal arrival area minimum 

altitudes are not specified.

Figure 4-38. RNAV approaches with and without TAAs.
4-59

A visual approach is an ATC authorization for an aircraft 

on an IFR flight plan to proceed visually to the airport of 

intended landing; it is not an IAP. Also, there is no missed 

approach segment. An aircraft unable to complete a visual 

approach must be handled as any other go-around and 

appropriate separation must be provided. A vector for a 

visual approach may be initiated by ATC if the reported 

ceiling at the airport of intended landing is at least 500 feet 

above the MVA/MIA and the visibility is 3 SM or greater. At 

airports without weather reporting service, there must be 

reasonable assurance through area weather reports and 

PIREPs that descent and approach to the airport can be 

made visually, and the pilot must be informed that weather 

information is not available.

The visual approach clearance is issued to expedite the flow 

of traffic to an airport. It is authorized when the ceiling is 

reported or expected to be at least 1,000 feet AGL and the 

visibility is at least 3 SM. Pilots must remain clear of the 

clouds at all times while conducting a visual approach. At 

an airport with a control tower, pilots may be cleared to fly a 

visual approach to one runway while others are conducting 

VFR or IFR approaches to another parallel, intersecting, or 

converging runway. Also, when radar service is provided, 

it is automatically terminated when the controller advises 

pilots to change to the tower or advisory frequency. While 

conducting a visual approach, the pilot is responsible for 

providing safe obstacle clearance. 

Contact Approaches

If conditions permit, pilots can request a contact approach, 

which is then authorized by the controller. A contact 

approach cannot be initiated by ATC. This procedure may 

be used instead of the published procedure to expedite 

arrival, as long as the airport has a SIAP the reported ground 

visibility is at least 1 SM, and pilots are able to remain clear 

of clouds with at least one statute mile flight visibility 

throughout the approach. Some advantages of a contact 

approach are that it usually requires less time than the 

published instrument procedure, it allows pilots to retain 

the IFR clearance, and provides separation from IFR and 

SVFR traffic. On the other hand, obstruction clearances and 

VFR traffic avoidance becomes the pilot’s responsibility. 

Unless otherwise restricted, the pilot may find it necessary 

to descend, climb, or fly a circuitous route to the airport to 

maintain cloud clearance or terrain/ obstruction clearance.

The main differences between a visual approach and 

a contact approach are: a pilot must request a contact 

approach, while a visual approach may be assigned by 

ATC or requested by the pilot; and a contact approach may 

be approved with 1 mile visibility if the flight can remain 

clear of clouds, while a visual approach requires the pilot 

to have the airport in sight, or a preceding aircraft to be 

followed, and the ceiling must be at least 1,000 feet AGL 

with at least 3 SM visibility.

Charted Visual Flight Procedures

A charted visual flight procedure (CVFP) may be established 

at some airports with control towers for environmental or 

noise considerations, as well as when necessary for the 

safety and efficiency of air traffic operations. Designed 

primarily for turbojet aircraft, CVFPs depict prominent 

landmarks, courses, and recommended altitudes to specific 

runways. When pilots are flying the Roaring Fork Visual RWY 

15, shown in Figure 4-36 , mountains, rivers, and towns 

provide guidance to Aspen, Colorado’s Sardy Field instead 

of VORs, NDBs, and DME fixes.

Pilots must have a charted visual landmark or a preceding 

aircraft in sight, and weather must be at or above the 

published minimums before ATC will issue a CVFP clearance. 

ATC will clear pilots for a CVFP if the reported ceiling at the 

airport of intended landing is at least 500 feet above the 

MVA/MIA, and the visibility is 3 SM or more, unless higher 

minimums are published for the particular CVFP. When 

accepting a clearance to follow a preceding aircraft, pilots 

are responsible for maintaining a safe approach interval 

and wake turbulence separation. Pilots must advise ATC if 

unable at any point to continue a charted visual approach 

or if the pilot loses sight of the preceding aircraft.

RNAV Approaches 

Because of the complications with database coding, 

naming conventions were changed in January 2001 to 

accommodate all approaches using RNAV equipment into 

one classification which is RNAV. This classification includes 

both ground- based and satellite dependent systems. 

Eventually all approaches that use some type of RNAV will 

reflect RNAV in the approach title.

This changeover is being made to reflect two shifts in 

instrument approach technology. The first shift is the 

use of the RNP concept outlined in Chapter 1, Departure 

Procedures, in which a single performance standard 

concept is being implemented for departure/approach 

procedure design. Through the use of RNP, the underlying 

system of navigation may not be required, provided the 

aircraft can maintain the appropriate RNP standard. The 

second shift is advanced avionics systems, such as FMS, 

used by most airlines, needed a new navigation standard by 

which RNAV could be fully integrated into the instrument 

approach system.

An FMS uses multi-sensor navigation inputs to produce 

a composite position. Essentially, the FMS navigation 
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Figure 4-39. Traditional GPS approach overlay.
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NOT FOR NAVIGATION

Figure 4-40. Lincoln Muni KLNK Lincoln, Nebraska, RNAV GPS RWY 14 approach.
4-62

function automatically blends or selects position sensors to 

compute aircraft position. Instrument approach charts and 

RNAV databases needed to change to reflect these issues. 

A complete discussion of airborne navigation databases 

is included in Chapter 6, Airborne Navigation Databases. 

Due to the multi- faceted nature of RNAV, new approach 

criteria have been developed to accommodate the design 

of RNAV instrument approaches. This includes criteria for 

terminal arrival areas (TAAs, RNAV basic approach criteria, 

and specific final approach criteria for different types of 

RNAV approaches.

Terminal Arrival Areas 

TAAs are the method by which aircraft equipped with a 

FMS and/or GPS are transitioned from the RNAV en route 

structure to the terminal area with minimal ATC interaction. 

TAAs are depicted in the planview of the approach chart, 

and each waypoint associated with them is also provided 

with a unique five character, pronounceable name. The TAA 

is not found on all RNAV approaches however, especially 

in areas of heavy concentration of air traffic. When the 

TAA is published, it replaces the MSA for that approach 

procedure. The TAA consists of a designated volume of 

airspace designed to allow aircraft to enter a protected 

area, offering guaranteed obstacle clearance where the 

initial approach course is intercepted based on the location 

of the aircraft relative to the airport. The RNAV procedure 

underlying the TAA is the “T” design (also called the “Basic 

T”) or a modification of the “T.” The “T” design incorporates 

from one to three IAFs: an IF that serves as a dual purpose IF 

(IAF): a FAF, and a missed approach point usually located at 

the runway threshold. The three IAFs are normally aligned 

in a straight line perpendicular to the intermediate course, 

which is an extension of the final course leading to the 

runway, forming a “T.” The initial segment is normally from 

3–6 NM in length; the intermediate 5–7 NM, and the final 

segment 5 NM. Specific segment length may be varied to 

accommodate specific aircraft categories for which the 

procedure is designed. However, the published segment 

lengths reflect the highest category of aircraft normally 

expected to use the procedure. [Figure 4-37 ]

Procedurally, pilots may be cleared to an IAF associated 

with the TAA. ATC expects the flight to proceed to the IAF 

and maintain the altitude depicted for that area of the TAA, 

unless cleared otherwise. An obstacle clearance of at least

1,000 feet is guaranteed within the boundaries of the TAA.

TAAs are modified or even eliminated, if necessary, to meet 

the requirements of a specific airport and surrounding 

terrain or airspace considerations negating the use of 

the “T” approach design concept. The “T” design may be 

modified by the procedure designers where required by 

terrain or ATC considerations. For instance, the “T” design 

may appear more like a regularly or irregularly shaped “Y,” 

or may even have one or both outboard IAFs eliminated 

resulting in an upside down “L” or an “I” configuration. 

Further, the leg lengths associated with the outboard IAFs 

may differ.

Another modification of the “T” design may be found at 

airports with parallel runway configurations. Each parallel 

runway may be served by its own “T” IAF, IF (IAF), and FAF 

combination, resulting in parallel final approach courses. 

Common IAFs may serve both runways; however, only 

the intermediate and final approach segments for the 

landing runway is shown on the approach chart. Alternative 

designs are addressed in FAA Order 8260.58. U.S Standard 

for Performance-Based Navigation (PBN) Instrument 

Procedure Design. Variations may eliminate one or both 

base areas, and/or limit or modify the angular size of the 

straight-in area. When both base areas are eliminated, TAAs 

are not depicted in the planview. Normally, a portion of 

the TAA underlies an airway. If this is not the case, at least 

one feeder route is provided from an airway fix or NAVAID 

to the TAA boundary. The feeder route provides a direct 

course from the en route fix/NAVAID to the appropriate 

IF/IAF. Multiple feeder routes may also be established. In 

some cases, TAAs may not be depicted because of airspace 

congestion or other operational requirements. [Figure 

4-38 ] 

RNAV Approach Types

RNAV encompasses a variety of underlying navigation 

systems and, therefore, approach criteria. This results in 

different sets of criteria for the final approach segment 

of various RNAV approaches. RNAV instrument approach 

criteria address the following procedures: 

•	 GPSoverlayofpre-existingnonprecisionapproaches.

•	 VOR/DME based RNAV approaches.

•	 Stand-alone RNAV (GPS) approaches.

•	 RNAV (GPS) approaches with vertical guidance

(APV). 

•	 RNAV (GPS) precision approaches (WAAS and

LAAS). 

GPS Overlay of Nonprecision Approach

The original GPS approach procedures provided 

authorization to fly non-precision approaches based 

on conventional, ground-based NAVAIDs. Many of 

these approaches have been converted to stand-alone 

approaches, and the few that remain are identified by 

the name of the procedure and “or GPS.” These GPS nonprecision approaches are predicated upon the design 
4-63

CAT II

100

0 150 700

Runway visual range (feet)

1,200 1,800 2,400

200

Decision height (feet AGL)

CAT IIIc

CAT IIIb CAT IIIa

CAT I

The lowest authorized ILS minimums, with all required ground and airborne systems components operative, are: 

CAT I - decision height (DH) 200 feet and runway visual range

(RVR) 2,400 feet (with touchdown zone and centerline lighting. 

RVR 1,800 feet).

CAT II - DH 100 feet and RVR 1,200 feet.

CAT IIIa - No DH or DH below 100 feet and RVR not less than 

700 feet.

CAT IIIb - No DH or DH below 50 feet and RVR less than 

700 feet but not less than 150 feet.

CAT IIIc - No DH and no RVR limitation.

NOTE: Special authorization and equipment are required 

 for CAT II and III.

Figure 4-42. ILS approach categories.

ILS final approach criteria (for primary protected airspace)

Final approach area

50,200 feet current and 50,000 feet previous

12,152 feet current

16,000 feet previous

1,400 feet current and 1,000 feet previous

200 feet current

and previous

Figure 4-41. ILS final approach segment design criteria.
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Figure 4-43. Category III approach procedure.

criteria of the ground-based NAVAID used as the basis of 

the approach. As such, they do not adhere to the RNAV 

design criteria for stand-alone GPS approaches, and are not 

considered part of the RNAV (GPS) approach classification 

for determining design criteria. [Figure 4-39 ] 
4-65

27 27

27 27 No transgression zone27 27 No transgression zone

Dependent Parallel Approaches

• Runway centerlines space 2,500 feet or greater

• Staggered approaches

• Final monitor controller NOT required

Independent Parallel Approaches

Simultaneous parallel approaches

• Runway centerlines spaced 4,300 

 feet or greater (duals and trips)

• Final monitor controllers required

PRM approaches 

(simultaneous close parallel)

• Runway centerlines spaced less than 

4,300 feet (Duals)

• Runways centerline spaced greater 

 than 4,300 feet (Triples)

• FMC

• PRM

27

27

• Runway centerlines spaced 2,500 feet or greater

• Radar monitoring required

• Staggered approaches

Dependant Parallel Approaches Diagonal separation

Figure 4-44. Parallel (dependent) ILS approach separation criteria.

GPS Stand-Alone/RNAV (GPS) Approach 

As of November 2010, there are approximately 419 GPS 

stand-alone approaches throughout the country. The 

number of GPS stand-alone approaches continues to 

decrease as they are replaced by RNAV approaches. RNAV 

(GPS) approaches are named so that airborne navigation 

databases can use either GPS or RNAV as the title of the 

approach. This is required for non-GPS approach systems, 

such as VOR/DME based RNAV systems. In the past, 

these approaches were often referred to as "stand-alone 

GPS" approaches. They are considered non-precision 

approaches, offering only LNAV and circling minimums. 

Precision minimums are not authorized, although LNAV/

VNAV minimums may be published and used as long as 

the on-board system is capable of providing approach 

approved VNAV. The RNAV (GPS) Runway 14 approach for 

Lincoln, Nebraska, incorporates only LNAV and circling 

minimums [Figure 4-40]. 

For a non-vertically guided straight-in RNAV (GPS) 

approach, the final approach course must be aligned within

15° of the extended runway centerline. The final approach 

segment should not exceed 10 NM, and when it exceeds

6 NM, a stepdown fix is typically incorporated. A minimum

of 250 feet obstacle clearance is also incorporated into the

final approach segment for straight-in approaches, and a 

maximum 400-feet per NM descent gradient is permitted.

The approach design criteria are different for approaches 

that use vertical guidance provided by a Baro-VNAV 

system. Because the Baro-VNAV guidance is advisory and 

not primary, Baro-VNAV approaches are not authorized in 

areas of hazardous terrain, nor are they authorized when 

a remote altimeter setting is required. Due to the inherent 

problems associated with barometric readings and cold 

temperatures, these procedures are also temperature 

limited. Additional approach design criteria for RNAV 

Approach Construction Criteria can be found in the 
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Figure 4-45. Sacramento International KSMF, Sacramento, California, ILS RWY 16L.
4-67

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NOT FOR NAVIGATION

Note indicates simultaneous (independent) approaches are authorized.

Figure 4-46. Charlotte Douglas International KCLT, Charlotte, North Carolina, ILS RWY 18.
4-68

26R 26L

7 NM

3,200'

2,200'

26L

26R

2,200'

2,200'

2,200'

3,200'

NO TRANSGRESSION ZONE (NTZ)

Note: Extend radar monitoring and no-transgression zone (NTZ) to 7 NM 

beyond runway departure end for quadruple simultaneous ILS approaches.

Radar monitoring provided to ensure aircraft do 

no penetrate the no-transgression zone (NTZ)

Intercept glideslope at 2,200 feet

Radar monitoring provided to 

ensure aircraft do no penetrate 

the no-transgression zone (NTZ)

Runway centerlines spaced 4,300 feet 

or more [dual runways] or 5,000 feet 

or more, [triple or quadruple runways]

—radar monitoring required.

Figure 4-47. Simultaneous parallel ILS approach criteria.

appropriate FAA Order 8260-series directives.

RNAV (GPS) Approach Using WAAS 

WAAS was commissioned in July 2003, with IOC. Although 

precision approach capability is still in the future, initial 

WAAS currently provides a new type of APV known as 

LPV. WAAS approaches consist of the following approach 

types: LPV, LNAV/VNAV, and LNAV. Approach minimums 

as low as 200 feet HAT and 1/2 SM visibility is possible, 

even though LPV is semi-precision and not considered a 

precision approach. WAAS covers 95 percent of the country 

95 percent of the time.

NOTE: WAAS avionics receive an airworthiness approval 

in accordance with Technical Standard Order (TSO) C-145, 

Airborne Navigation Sensors Using the (GPS) Augmented 

by the Wide Area Augmentation System (WAAS), or TSO146, Stand-Alone Airborne Navigation Equipment Using 

the Global Positioning System (GPS) Augmented by the 

Wide Area Augmentation System (WAAS), and installed 

in accordance with AC 20-130, Airworthiness Approval 

of Navigation or Flight Management Systems Integrating 

Multiple Navigation Sensors, or AC 20-138, Airworthiness 

Approval of Positioning and Navigation Systems.

Precision approach capability will become available as more 

GBAS (LAAS) approach types become operational. GBAS 

(LAAS) further increases the accuracy of GPS and improves 

signal integrity warnings. Precision approach capability 

requires obstruction planes and approach lighting systems 

to meet Part 77 standards for ILS approaches. This delays 

the implementation of RNAV (GPS) precision approach 

capability due to the cost of certifying each runway.

ILS Approaches 

Notwithstanding emerging RNAV technology, the ILS is the 

most precise and accurate approach NAVAID currently in 

use throughout the NAS. An ILS CAT I precision approach 

allows approaches to be made to 200 feet above the TDZE 

and with visibilities as low as 1,800 RVR; with CAT II and CAT 

III approaches allowing descents and visibility minimums 

that are even lower. Non-precision approach alternatives 

cannot begin to offer the precision or flexibility offered by 

an ILS. In order to further increase the approach capacity 

of busy airports and exploit the maximum potential of ILS 
4-69

26L

8R

26R

8L

APUSA INT established where 3,200 feet

altitude intercepts glideslope NTZ begins

Radar monitoring provided to 0.5 

NM beyond departure and to 

ensure separation during 

simultaneous missed approaches

Radar monitoring provided to ensure 

lateral or vertical separation between 

aircraft on parallel localizers prior to 

the beginning of the NTZ

0.5 NM

0.5 NM

Runway centerlines spaced less than 

4,300 feet apart, radar monitoring and 

PRM required

3,200 feet

2,200 feet

NO TRANSGRESSION ZONE (NTZ)

Intercept glideslope at 2,200 feet

Figure 4-48. Simultaneous close parallel ILS approach ILS PRM criteria.

technology, many different applications are in use.

A single ILS system can accommodate 29 arrivals per hour 

on a single runway. Two or three parallel runways operating 

consecutively can double or triple the capacity of the 

airport. For air commerce, this means greater flexibility 

in scheduling passenger and cargo service. Capacity is 

increased through the use of parallel (dependent) ILS, 

simultaneous parallel (independent) ILS, simultaneous 

close parallel (independent) ILS, precision runway 

monitor (PRM), and converging ILS approaches. A parallel 

(dependent) approach differs from a simultaneous 

(independent) approach in that the minimum distance 

between parallel runway centerlines is reduced; there is 

no requirement for radar monitoring or advisories; and a 

staggered separation of aircraft on the adjacent localizer/ 

azimuth course is required.

In order to successfully accomplish parallel, simultaneous 

parallel, and converging ILS approaches, flight crews 

and ATC have additional responsibilities. When multiple 

instrument approaches are in use, ATC advises flight 

crews either directly or through ATIS. It is the pilot’s 

responsibility to inform ATC if unable or unwilling to 

execute a simultaneous approach. Pilots must comply 

with all ATC requests in a timely manner and maintain 

strict radio discipline, including using complete aircraft 

call signs. It is also incumbent upon the flight crew to 

notify ATC immediately of any problems relating to aircraft 

communications or navigation systems. At the very least, 

the approach procedure briefing should cover the entire 

approach procedure including the approach name, runway 
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Parallel runways used for PRM operations

Specifies dual VHF and additional information

Figure 4-49. St Louis, Missouri, ILS PRM RWY 11.
4-71

number, frequencies, final approach course, glideslope 

intercept altitude, DA or DH, and the missed approach 

instructions. The review of autopilot procedures is also 

appropriate when making coupled ILS or MLS approaches.

As with all approaches, the primary navigation responsibility 

falls upon the pilot in command. ATC instructions will be 

limited to ensuring aircraft separation. Additionally, MAPs 

are normally designed to diverge in order to protect all 

involved aircraft. ILS approaches of all types are afforded 

the same obstacle clearance protection and design 

criteria, no matter how capacity is affected by multiple ILS 

approaches. [Figure 4-41 ]

ILS Approach Categories 

There are three general classifications of ILS approaches: 

CAT I, CAT II, and CAT III (autoland). The basic ILS approach is 

a CAT I approach and requires only that pilots be instrument 

rated and current, and that the aircraft be equipped 

appropriately. CAT II and CAT III ILS approaches typically 

have lower minimums and require special certification for 

operators, pilots, aircraft, and airborne/ground equipment. 

Because of the complexity and high cost of the equipment, 

CAT III ILS approaches are used primarily in air carrier and 

military operations. [Figure 4-42 ]

CAT II and III Approaches 

The primary authorization and minimum RVRs allowed 

for an air carrier to conduct CAT II and III approaches 

can be found in OpSpecs Part C. CAT II and III operations 

allow authorized pilots to make instrument approaches in 

weather that would otherwise be prohibitive.

While CAT I ILS operations permit substitution of midfield 

RVR for TDZ RVR (when TDZ RVR is not available), CAT II ILS 

operations do not permit any substitutions for TDZ RVR. 

The TDZ RVR system is required and must be used. The TDZ 

RVR is controlling for all CAT II ILS operations.

The weather conditions encountered in CAT III operations 

range from an area where visual references are adequate 

for manual rollout in CAT IIIa, to an area where visual 

references are inadequate even for taxi operations in CAT 

IIIc. To date, no U.S. operator has received approval for CAT 

IIIc in OpSpecs. Depending on the auto-flight systems, 

some airplanes require a DH to ensure that the airplane is 

going to land in the TDZ and some require an Alert Height 

as a final cross-check of the performance of the auto-flight 

systems. These heights are based on radio altitude (RA) and 

can be found in the specific aircraft’s AFM. [Figure 4-43 ]

Both CAT II and III approaches require special ground and 

airborne equipment to be installed and operational, as 

well as special aircrew training and authorization. The 

OpSpecs of individual air carriers detail the requirements 

of these types of approaches, as well as their performance 

criteria. Lists of locations where each operator is approved 

to conduct CAT II and III approaches can also be found in 

the OpSpecs.

Special Authorization CAT I and Special Authorization CAT III 

are approaches designed to take advantage of advances in 

flight deck avionics and technologies like Head-Up Displays 

(HUD) and automatic landings. There are extensive ground 

infrastructures and lighting requirements for standard CAT 

II/III, and the Special Authorization approaches mitigate 

the lack of some lighting with the modern avionics found 

in many aircraft today. Similar to standard CAT II/III, an air 

carrier must be specifically authorized to conduct Special 

Authorization CAT I/II in OpSpecs Part C.

ILS Approaches To Parallel Runways

Airports that have two or three parallel runways may be 

authorized to use parallel approaches to maximize the 

capacity of the airport. There are three classifications 

of parallel ILS approaches, depending on the runway 

centerline separation and ATC procedures. 

Parallel (Dependent) ILS Approaches

Parallel (dependent) ILS approaches are allowed at airports 

with parallel runways that have centerlines separated by 

at least 2,500 feet. Aircraft are allowed to fly ILS and other 

approaches to parallel runways; however, the aircraft must 

be staggered by a minimum of 11⁄2 NM diagonally. Aircraft 

are staggered by 2 NM diagonally for runway centerlines 

that are separated by more than 4,300 feet and up to but 

not including 9,000 feet, and that do not have final monitor 

air traffic controllers. Radar separation is provided between 

aircraft participating in parallel (dependent) approach 

operations. [Figure 4-44 ] Recently, RNAV procedures with 

vertical guidance will be permitted to participate in all 

parallel (dependent) approach operations.

Where this type of approach is approved, each approach 

plate indicates the other runway with which simultaneous 

approaches can be conducted. For example, “Simultaneous 

approaches authorized with runway 12L”. Until the 

approach plates for all such runway pairs can be modified 

to include this note, P-NOTAMS will be issued identifying 

such operations. ATC normally communicates an advisory 

over ATIS that parallel approach procedures are in effect. 

For example, pilots flying into Sacramento, California, may 

encounter parallel approach procedures. [Figure 4-45 ] 

Simultaneous Parallel ILS Approaches

Simultaneous parallel ILS approaches are used at authorized 
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Figure 4-50. Simultaneous offset instrument approach procedure.
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NE-3, 23 AUG 2012 to 20 SEP 2012

Figure 4-51. Converging approach criteria.
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SC-2, 16 DEC 2010 to 13 JAN 2011

NOT FOR NAVIGATION

Indicates runways authorized for converging approach operations

Figure 4-52. Dallas-Fort Worth KDFW, Dallas-Fort Worth, Texas, CONVERGING ILS RWY 35C.
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SE-4, 16 DEC 2010 to 13 JAN 2011

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On-airport VOR facility

Figure 4-53. Fort Rucker, Alabama, KOZR VOR RWY 6.

airports that have between 4,300 feet and 9,000 feet 

separation between runway centerlines. A dedicated final 

monitor controller is required to monitor separation for this 

type of approach, which eliminates the need for staggered 

approaches. Final monitor controllers track aircraft positions 

and issue instructions to pilots of aircraft observed deviating 

from the LOC course. [Figure 4-46 ] As of March 2010, 

RNAV approach procedures with vertical guidance will 

be permitted to conduct simultaneous parallel approach 

operations.

Triple simultaneous approaches are authorized provided the 

runway centerlines are separated by at least 5,000 feet, or

4,300 feet with PRM, and are below 1,000 feet MSL airport 

elevation. Additionally, for triple parallel approaches above 

airport elevations of 1,000 feet MSL, ASR with high-resolution 

final monitor aids or high update RADAR with associated 

final monitor aids is required.

As a part of the simultaneous parallel approach approval, 

normal operating zones (NOZ) and no-transgression zones 

(NTZ) must be established to ensure proper flight track 

boundaries for all aircraft. The NOZ is the operating zone 

within which aircraft remain during normal approach 

operations. The NOZ is typically no less than 1,400 feet 

wide, with 700 feet of space on either side of the runway 

centerline. A NTZ is a 2,000-foot wide area located between 

the parallel runway final approach courses. It is equidistant 
4-76

SC-4, 16 DEC 2010 to 13 JAN 2011

SC-4, 16 DEC 2010 to 13 JAN 2011

NOT FOR NAVIGATION

FAF

AEX VOR is an off-airport facility

Figure 4-54. Alexandria International (AEX), Alexandria, Louisiana, KAEX VOR DME RWY 32.
4-77

SC-2, 16 DEC 2010 to 13 JAN 2011

SC-2, 16 DEC 2010 to 13 JAN 2011

NOT FOR NAVIGATION

On-airport NDB facility

Figure 4-55. Carthage/Panola County-Sharpe Field, Carthage, Texas, (K4F2), NDB RWY 35.

between the runways and indicates an area within which 

flight is not authorized. [Figure 4-47 ] Any time an aircraft 

breaches the NTZ, ATC issues instructions for all aircraft to 

break off the approach to avoid potential conflict.

Simultaneous Close Parallel ILS Precision 

Runway Monitor Approaches 

Simultaneous close parallel (independent) ILS PRM 

approaches are authorized for use at airports that have 

parallel runways separated by at least 3,400 feet and no 

more than 4,300 feet. [Figure 4-48 ] They are also approved 

for airports with parallel runways separated by at least 3,000 

feet with an offset LOC where the offset angle is at least 

2.5° but no more than 3°. Other offset LOC approaches to 

lesser runway spacing are referred to as Simultaneous Offset 

Instrument Approaches (SOIA) and are discussed in depth 

later in this chapter.

The PRM system provides the ability to accomplish 

simultaneous close parallel (independent) ILS approaches 

and enables reduced delays and fuel savings during reduced 

visibility operations. It is also the safest method of increasing 

ILS capacity through the use of parallel approaches. The 

PRM system incorporates high-update radar with one 

second or better update time and a high resolution ATC 

radar display that contains automated tracking software 

that can track aircraft in real time. Position and velocity is 

updated each second and a ten second projected position 

is displayed. The system also incorporates visual and aural 

alerts for the controllers.

Approval for ILS PRM approaches requires the airport to 
4-78

SW-4, 16 DEC 2010 to 13 JAN 2011

SW-4, 16 DEC 2010 to 13 JAN 2011

NOT FOR NAVIGATION FAF

On-airport NDB facility NDB/DME FAF

Figure 4-56. Tucson/Ryan Field, Tuscson, Arizona, (KRYN), NDB/DME or GPS RWY 6R.
4-79

N1

10266

RADAR MINS

ASHEVILLE, NC Amdt. 5A, NOV 18, 1998 (FAA) E LE V 2165

ASHEVILLE RGNL

RADAR - 124.65 269.575

HAT / HAT /

DA/ HATh/ DA/ HATh/

RWY GS/TCH/RPI CAT MDA-VIS HAA CEIL-VIS CAT MDA-VIS HAA CEIL-VIS

ASR 34 AB 2800 /24 660 (700-1⁄2) C 2800 /60 660 (700-11⁄4)

D 2800 -11⁄2 660 (700-11⁄2)

16 A 3000 /50 835 (900-1) B 3000 /60 835 (900-11⁄4)

C 3000 -21⁄2 835 (900-21⁄2) D 3000 -23⁄4 835 (900-23⁄4)

C IR C L ING A 3000 -1 835 (900-1) B 3000 -11⁄4 835 (900-11⁄4)

C 3000 -21⁄2 835 (900-21⁄2) D 3000 -23⁄4 835 (900-23⁄4)

Circling not authorized west of Rwy 16-34. Night circling not authorized.

BEAUFORT, SC Amdt. 3A, NOV 20, 2008 (FAA) E LE V 10

BEAUFORT COUNTY

RADAR -1 118.45 292.125 NA

HAT / HAT /

DA/ HATh/ DA/ HATh/

RWY GS/TCH/RPI CAT MDA-VIS HAA CEIL-VIS CAT MDA-VIS HAA CEIL-VIS

16 DEC

N 2011

NOT FOR NAVIGATION

RADAR INSTRUMENT APPROACH MINIMUMS

Figure 4-57. Asheville Regional KAVL, Asheville, North Carolina, radar instrument approach minimums.

have a precision runway monitoring system and a final 

monitor controller who can only communicate with aircraft 

on the final approach course. Additionally, two tower 

frequencies are required to be used and the controller 

broadcasts over both frequencies to reduce the chance of 

instructions being missed. Pilot training is also required for 

pilots using the PRM system. Part 121 and 135 operators are 

required to complete training that includes the viewing of 

videos. The FAA PRM website (http://www.faa.gov/training 

_testing/training/prm) contains training information for 

PRM approaches and is a location from which the videos 

can be seen and/or downloaded.

When pilots or flight crews wish to decline a PRM approach, 

ATC must be notified immediately and the flight will be 

transitioned into the area at the convenience of ATC. Pilots

 who are unable to accept a PRM approach may be subject 

to delays.

The approach chart for the PRM approach typically requires 

two pages and outlines pilot, aircraft, and procedure 

requirements necessary to participate in PRM operations. 

[Figure 4-49 ] Pilots need to be aware of the differences 

associated with this type of ILS approach which are listed 

below:

•	 Immediately follow break out instructions as soon

as safety permits.

•	 Listen concurrently to the tower and the PRM

monitor to avoid missed instructions from stuck 

mikes or blocked transmissions. The final ATC 

controller can override the radio frequency if 

necessary.

•	 Broadcast only over the main tower frequency.

•	 Disengage the autopilot for breakouts because

hand- flown breakouts are quicker.

•	 Set the Traffic Alert and Collision Avoidance System

(TCAS) to the appropriate TA (traffic advisory) or 

RA (resolution advisory) mode in compliance with 

current operational guidance on the attention all 

users page (AAUP), or other authorized guidance 

(i.e., approved flight manual, flight operations 

manual. It is important to note that descending 

breakouts may be issued. Additionally, flight crews 

are never issued breakout instructions that clear 

them below the MVA, and they are not required to 

descend at more than 1,000 fpm.

Simultaneous Offset Instrument Approaches 

(SOIAs) 

SOIAs allow simultaneous approaches to two parallel 

runways spaced at least 750 feet apart, but less than 3,000 

feet. The SOIA procedure utilizes an ILS/PRM approach 

to one runway and an offset localizer-type directional 

aid (LDA)/PRM approach with glideslope to the adjacent 
4-80

Obstacle clearance surface (OCS)

Glideslope 2.5° - 3.0°

954

Ground point of intercept (GPI)

34:1 visual segment

Figure 4-58. PAR final approach area criteria.

runway. The use of PRM technology is also required with 

these operations; therefore, the approach charts will 

include procedural notes, such as “Simultaneous approach 

authorized with LDA PRM RWY XXX.” San Francisco had the 

first published SOIA approach. [Figure 4-50 ]

The training, procedures, and system requirements for 

SOIA ILS/PRM and LDA/PRM approaches are identical 

with those used for simultaneous close parallel ILS/PRM 

approaches until near the LDA/PRM approach MAP, where 

visual acquisition of the ILS aircraft by the LDA aircraft must 

be accomplished. If visual acquisition is not accomplished 

prior to reaching the LDA MAP , a missed approach must 

be executed. A visual segment for the LDA/PRM approach 

is established between the LDA MAP and the runway 

threshold. Aircraft transition in visual conditions from 

the LDA course, beginning at the LDA MAP, to align with 

the runway and can be stabilized by 500 feet AGL on the 

extended runway centerline. Pilots are reminded that they 

are responsible for collision avoidance and wake turbulence 

mitigation between the LDA MAP and the runway. 

The FAA website has additional information about PRM 

and SOIA, including instructional videos at http://www.

faa.gov/training_testing/training/prm.

Converging ILS Approaches

Another method by which ILS approach capacity can be 

increased is through the use of converging approaches. 

Converging approaches may be established at airports 

that have runways with an angle between 15° and 100° 

and each runway must have an ILS. Additionally, separate 

procedures must be established for each approach, and 

each approach must have a MAP at least 3 NM apart with 

no overlapping of the protected missed approach airspace. 

Only straight-in approaches are approved for converging 

ILS procedures. If the runways intersect, the controller must 

be able to visually separate intersecting runway traffic.

Approaches to intersecting runways also have higher 

minimums with a 700-foot minimum and no less than 2 

SM visibility. Pilots are informed of the use of converging 

ILS approaches by the controller upon initial contact or 

through ATIS. [Figure 4-51 ]

Dallas/Fort Worth International airport is one of the few 

airports that makes use of converging ILS approaches 

because its runway configuration has multiple parallel 

runways and two offset runways. [Figure 4-52 ] The 

approach chart title indicates the use of converging 

approaches and the notes section highlights other runways 

that are authorized for converging approach procedures.

VOR Approach 

The VOR is one of the most widely used non-precision 

approach types in the NAS. VOR approaches use VOR 

facilities both on and off the airport to establish approaches 

and include the use of a wide variety of equipment, such 

as DME and TACAN. Due to the wide variety of options 

included in a VOR approach, TERPS outlines design criteria 

for both on and off airport VOR facilities, as well as VOR 

approaches with and without a FAF. Despite the various 

configurations, all VOR approaches are non-precision 

approaches, require the presence of properly operating 

VOR equipment, and can provide MDAs as low as 250 feet 

above the runway. VOR also offers a flexible advantage in 

that an approach can be made toward or away from the 

navigational facility.

The VOR approach into Fort Rucker, Alabama, is an example 

of a VOR approach where the VOR facility is on the airport 

and there is no specified FAF. [Figure 4-53 ] For a straightin approach, the final approach course is typically aligned 

to intersect the extended runway centerline 3,000 feet 

from the runway threshold, and the angle of convergence 
4-81

SC-4, 16 DEC 2010 to 13 JAN 2011

SC-4, 16 DEC 2010 to 13 JAN 2011

NOT FOR NAVIGATION

Figure 4-59. Vicksburg Tallulah Regional KTVR, Tallulah Vicksburg, Louisiana, LOC RWY 36.
4-82

NOT FOR NAVIGATION

SE-2, 16 DEC 2010 ot 13 JAN 2011

SE-2, 16 DEC 2010 to 13 JAN 2011

Figure 4-60. Davidson County KEXX, Lexington, North Carolina, LOC DME RWY 6.
4-83

SE-3, 16 DEC 2010 to 13 JAN 2011

SE-3, 16 DEC 2010 to 13 JAN 2011

NOT FOR NAVIGATION

Figure 4-61. Dayton Beach International DAB, Dayton Beach, Florida, LOC BC RWY 25R.
4-84

between the two does not exceed 30°. This type of VOR 

approach also includes a minimum of 300 feet of obstacle 

clearance in the final approach area. The final approach 

area criteria include a 2 NM wide primary area at the facility 

that expands to 6 NM wide at a distance of 10 NM from 

the facility. Additional approach criteria are established 

for courses that require a high altitude teardrop approach 

penetration.

When DME is included in the title of the VOR approach, 

operable DME must be installed in the aircraft in order to 

fly the approach from the FAF. The use of DME allows for an 

accurate determination of position without timing, which 

greatly increases situational awareness throughout the 

approach. Alexandria, Louisiana, is an excellent example 

of a VOR/DME approach in which the VOR is off the airport 

and a FAF is depicted. [Figure 4-54 ] In this case, the final 

approach course is a radial or straight-in final approach and 

is designed to intersect the runway centerline at the runway 

threshold with the angle of convergence not exceeding 30°.

The criteria for an arc final approach segment associated 

with a VOR/DME approach is based on the arc being 

beyond 7 NM and no farther than 30 NM from the VOR 

and depends on the angle of convergence between the 

runway centerline and the tangent of the arc. Obstacle 

clearance in the primary area, which is considered the area 

4 NM on either side of the arc centerline, is guaranteed by 

at least 500 feet.

NDB Approach 

Like the VOR approach, an NDB approach can be designed 

using facilities both on and off the airport, with or without 

a FAF, and with or without DME availability. At one time, 

it was commonplace for an instrument student to learn 

how to fly an NDB approach, but with the growing use of 

GPS, many pilots no longer use the NDB for instrument 

approaches. New RNAV approaches are also rapidly being 

constructed into airports that are served only by NDB. The 

long-term plan includes the gradual phase out of NDB 

facilities, and eventually, the NDB approach becomes 

nonexistent. Until that time, the NDB provides additional 

availability for instrument pilots into many smaller, remotely 

located airports.

The NDB Runway 35 approach at Carthage/Panola County 

Sharpe Field is an example of an NDB approach established 

with an on-airport NDB that does not incorporate a FAF. 

[Figure 4-55 ] In this case, a procedure turn or penetration 

turn is required to be a part of the approach design. For 

the NDB to be considered an on-airport facility, the facility 

must be located within one mile of any portion of the 

landing runway for straight-in approaches and within one 

mile of any portion of usable landing surface for circling 

approaches. The final approach segment of the approach 

is designed with a final approach area that is 2.5 NM wide 

at the facility and increases to 8 NM wide at 10 NM from 

the facility. Additionally, the final approach course and 

the extended runway centerline angle of convergence 

cannot exceed 30° for straight-in approaches. This type of 

NDB approach is afforded a minimum of 350 feet obstacle 

clearance.

When a FAF is established for an NDB approach, the 

approach design criteria changes. It also takes into account 

whether or not the NDB is located on or off the airport. 

Additionally, this type of approach can be made both 

moving toward or away from the NDB facility. The Tuscon 

Ryan Field, NDB/DME RWY 6 is an approach with a FAF 

using an on-airport NDB facility that also incorporates the 

use of DME. [Figure 4-56 ] In this case, the NDB has DME 

capabilities from the LOC approach system installed on the 

airport. While the alignment criteria and obstacle clearance 

remain the same as an NDB approach without a FAF, the 

final approach segment area criteria changes to an area that 

is 2.5 NM wide at the facility and increases to 5 NM wide,

15 NM from the NDB.

Radar Approaches 

The two types of radar approaches available to pilots when 

operating in the NAS are precision approach radar (PAR) and 

airport surveillance radar (ASR). Radar approaches may be 

given to any aircraft at the pilot’s request. ATC may also offer 

radar approach options to aircraft in distress regardless of 

the weather conditions or as necessary to expedite traffic. 

Despite the control exercised by ATC in a radar approach 

environment, it remains the pilot’s responsibility to ensure 

the approach and landing minimums listed for the approach 

are appropriate for the existing weather conditions 

considering personal approach criteria certification and 

company OpSpecs.

Perhaps the greatest benefit of either type of radar approach 

is the ability to use radar to execute a no gyro approach. 

Assuming standard rate turns, ATC can indicate when to 

begin and end turns. If available, pilots should make use of 

this approach when the heading indicator has failed and 

partial panel instrument flying is required.

Information about radar approaches is published in tabular 

form in the front of the TPP booklet. PAR, ASR, and circling 

approach information including runway, DA, DH, or MDA, 

height above airport (HAA), HAT, ceiling, and visibility criteria 

are outlined and listed by specific airport.

Regardless of the type of radar approach in use, ATC 
4-85

NOT FOR NAVIGATION

NE-1, 16 DEC 2010 to 13 JAN 2011

NE-1, 16 DEC 2010 to 13 JAN 2011

Figure 4-62. Hartford Brainard KHFD, Hartford, Connecticut, LDA RWY 2.
4-86

NC-3, 16 DEC 2010 to 13 JAN 2011

NC-3, 16 DEC 2010 to 13 JAN 2011

NOT FOR NAVIGATION

Figure 4-63. Lebanon Floyd W Jones, Lebonon, Missouri, SDF RWY 36.
4-87

monitors aircraft position and issues specific heading 

and altitude information throughout the entire approach. 

Particularly, lost communications procedures should 

be briefed prior to execution to ensure pilots have a 

comprehensive understanding of ATC expectations if radio 

communication were lost. ATC also provides additional 

information concerning weather and missed approach 

instructions when beginning a radar approach. [Figure 

4-57 ]

Precision Approach Radar (PAR)

PAR provides both vertical and lateral guidance, as well as 

range, much like an ILS, making it the most precise radar 

approach available. The radar approach, however, is not 

able to provide visual approach indications in the flight 

deck. This requires the flight crew to listen and comply 

with controller instructions. PAR approaches are rare, with 

most of the approaches used in a military setting; any 

opportunity to practice this type of approach is beneficial 

to any flight crew.

The final approach course of a PAR approach is normally 

aligned with the runway centerline, and the associated 

glideslope is typically no less than 2.5° and no more than 3°. 

Obstacle clearance for the final approach area is based on 

the particular established glideslope angle and the exact 

formula is outlined in Order 8260.3, Volume 3, Chapter 3. 

[Figure 4-58 ] practice this type of approach is beneficial 

to any flight crew. 

The final approach course of a PAR approach is normally 

aligned with the runway centerline, and the associated 

glideslope is typically no less than 2.5° and no more than 3°. 

Obstacle clearance for the final approach area is based on 

the particular established glideslope angle and the exact 

formula is outlined in Order 8260.3, Volume 3, Chapter 3. 

[Figure 4-56] 

Airport Surveillance Radar (ASR)

ASR approaches are typically only approved when 

necessitated for an ATC operational requirement or in an 

unusual or emergency situation. This type of radar only 

provides heading and range information, although the 

controller can advise the pilot of the altitude where the 

aircraft should be based on the distance from the runway. 

An ASR approach procedure can be established at any radar 

facility that has an antenna within 20 NM of the airport 

and meets the equipment requirements outlined in FAA 

Order 8200.1, U.S. Standard Flight Inspection Manual. ASR 

approaches are not authorized for use when Center Radar 

ARTS processing (CENRAP) procedures are in use due to 

diminished radar capability.

The final approach course for an ASR approach is aligned 

with the runway centerline for straight-in approaches 

and aligned with the center of the airport for circling 

approaches. Within the final approach area, the pilot is also 

guaranteed a minimum of 250 feet obstacle clearance. ASR 

descent gradients are designed to be relatively flat, with an 

optimal gradient of 150 feet per mile and never exceeding 

300 feet per mile.

Localizer Approaches

As an approach system, the localizer is an extremely flexible 

approach aid that, due to its inherent design, provides 

many applications for a variety of needs in instrument 

flying. An ILS glideslope installation may be impossible due 

to surrounding terrain. For whatever reason, the localizer 

is able to provide four separate applications from one 

approach system:

•	 Localizer approach

•	 Localizer/DME approach

•	 Localizer back course approach

•	 Localizer-type directional aid (LDA)

Localizer and Localizer DME

The localizer approach system can provide both precision 

and non-precision approach capabilities to a pilot. As a part 

of the ILS system, the localizer provides horizontal guidance 

for a precision approach. Typically, when the localizer is

discussed, it is thought of as a non-precision approach 

due to the fact that either it is the only approach system 

installed, or the glideslope is out of service on the ILS. In 

either case, the localizer provides a non-precision approach 

using a localizer transmitter installed at a specific airport. 

[Figure 4-59 ]

TERPS provides the same alignment criteria for a localizer 

approach as it does for the ILS, since it is essentially the 

same approach without vertical guidance stemming from 

the glideslope. A localizer is always aligned within 3° of the 

runway, and it is afforded a minimum of 250 feet obstacle 

clearance in the final approach area. In the case of a 

localizer DME (LOC DME) approach, the localizer installation 

has a collocated DME installation that provides distance 

information required for the approach. [Figure 4-60 ]

Localizer Back Course

In cases where an ILS is installed, a back course may be 

available in conjunction with the localizer. Like the localizer, 

the back course does not offer a glideslope, but remember 

that the back course can project a false glideslope signal 

and the glideslope should be ignored. Reverse sensing 
4-88

occurs on the back course using standard VOR equipment. 

With a horizontal situation indicator (HSI) system, reverse 

sensing is eliminated if it is set appropriately to the front 

course. [Figure 4-61 ]

Localizer-Type Directional Aid (LDA)

The LDA is of comparable use and accuracy to a localizer 

but is not part of a complete ILS. The LDA course usually 

provides a more precise approach course than the similar 

simplified directional facility (SDF) installation, which may 

have a course width of 6° or 12°.

The LDA is not aligned with the runway. Straight-in 

minimums may be published where alignment does 

not exceed 30° between the course and runway. Circling 

minimums only are published where this alignment 

exceeds 30°.

A very limited number of LDA approaches also incorporate 

a glideslope. These are annotated in the plan view of the 

instrument approach chart with a note, “LDA/Glideslope.” 

These procedures fall under a newly defined category of 

approaches called Approach (Procedure) with Vertical 

Guidance (aviation) APVs. LDA minima for with and without 

glideslope is provided and annotated on the minima lines 

of the approach chart as S−LDA/GS and S−LDA. Because 

the final approach course is not aligned with the runway 

centerline, additional maneuvering is required compared 

to an ILS approach. [Figure 4-62 ]

Simplified Directional Facility (SDF)

The SDF provides a final approach course similar to that of 

the ILS localizer. It does not provide glideslope information. 

A clear understanding of the ILS localizer and the additional 

factors listed below completely describe the operational 

characteristics and use of the SDF. [Figure 4-63 ]

The approach techniques and procedures used in an SDF 

instrument approach are essentially the same as those 

employed in executing a standard localizer approach 

except the SDF course may not be aligned with the runway 

and the course may be wider, resulting in less precision. 

Like the LOC type approaches, the SDF is an alternative 

approach that may be installed at an airport for a variety 

of reasons, including terrain. The final approach is provided 

a minimum of 250 feet obstacle clearance for straight-in 

approaches while in the final approach area, which is an 

area defined for a 6° course: 1,000 feet at or abeam the 

runway threshold expanding to 19,228 feet (10 NM) from 

the threshold. The same final approach area for a 12° 

course is larger. This type of approach is also designed 

with a maximum descent gradient of 400 feet per NM, 

unless circling only minimums are authorized.of reasons, 

including terrain. The final approach is provided a minimum 

of 250 feet obstacle clearance for straight-in approaches 

while in the final approach area, which is an area defined 

for a 6° course: 1,000 feet at or abeam the runway threshold 

expanding to 19,228 feet (10 NM) from the threshold. The 

same final approach area for a 12° course is larger. This type 

of approach is also designed with a maximum descent 

gradient of 400 feet per NM, unless circling only minimums 

are authorized.
5-1

Introduction

In the upcoming years, exciting new technologies will 

be developed and implemented to help ease air traffic 

congestion, add to system capacity, and enhance safety. 

Some of these seamless changes will be invisible to 

pilots. Others will entail learning new procedures, aircraft 

equipment, and systems that will introduce powerful new 

capabilities and dramatically increase the safety of all flight 

operations. 

Improvement Plans

Chapter 5
5-2

Figure 5-1. Next Generation Air Transportation System (NEXGEN) introduces new technological innovations for weather forecasting, 

digital communications, and networking.

Flight Data

Global 

Harmonization

Equivalent

Visual Operations

Policy & Regulations Super Density 

Operations

ICAO

DOT

FAA DOD DHS DOC NASA OSTP

NGATS 

Institute

Geospatial 

Information Communication Performance Metrics

Position, Navigation,

and Timing Safety

Network-Enabled Information Acess

Weather

Airport Operations and Support

Flight Operations and Support

Air Navigation Operations and Support

Net Centric Infrastructure Services

Flight Planning Aeronautical 

Information

Environment Layered

Adaptive Security Surveillance

Enterprise Services

State/Local 

Government

Industry &

Community

Next Generation Air Transportation (NextGen) 

System

Next Generation Air Transportation System (NextGen) is a 

comprehensive overhaul of the National Airspace System 

(NAS) designed to make air travel more convenient and 

dependable, while ensuring flights are as safe and secure 

as possible. It moves away from ground-based surveillance 

and navigation to new and more dynamic satellite-based 

systems and procedures, and introduces new technological 

innovations in areas such as weather forecast, digital 

communications, and networking. [Figure 5-1] When fully 

implemented, NextGen will safely allow aircraft to fly more 

closely together on more direct routes, reducing delays, 

and providing unprecedented benefits for the environment 

and the economy through reductions in carbon emissions, 

fuel consumption, and noise. [Figure 5-2]

Implementation in stages across the United States is due 

between 2012 and 2025. In order to implement NextGen, 

the Federal Aviation Administration (FAA) will undertake

a wide-range transformation of the entire United States air 

transportation system. NextGen consists of the following 

five systems:

1. Automatic dependent surveillance-broadcast 

(ADS-B)—will use the global positioning system 

(GPS) satellite signals to provide air traffic control 

(ATC) and pilots with more accurate information 

that keeps aircraft safely separated in the sky and on 

runways. [Figure 5-3] Aircraft transponders receive 

GPS signals and use them to determine the aircraft’s 

precise position in the sky. This and other data is 

then broadcast to other aircraft and ATC. Once fully 

established, both pilots and ATC will, for the first 

time, see the same real-time display of air traffic, 

substantially improving safety. The FAA will mandate 

the avionics necessary for implementing ADS-B.

2. System wide information management (SWIM)— 

will provide a single infrastructure and information 

management system to deliver high quality, timely 

data to many users and applications. By reducing 
5-3

Figure 5-2. Satellite-based navigation and tracking allows more aircraft to fly closely together on more direct routes. 

Figure 5-3. Automatic Dependent Surveillance-Broadcast (ADS-B) 

systems. 

the number and types of interfaces and systems, 

SWIM will reduce data redundancy and better 

facilitate multi- user information sharing. SWIM 

will also enable new modes of decision-making as 

information is more easily accessed. [Figure 5-4]

3. Next generation data communications—current 

communications between aircrew and ATC, and 

between air traffic controllers, are largely realized 

through voice communications. Initially, the 

introduction of data communications will provide 

an additional means of two-way communication 

for ATC clearances, instructions, advisories, flight 

crew requests, and reports. With the majority of 

aircraft data link equipped, the exchange of routine 

controller-pilot messages and clearances via data 

link will enable controllers to handle more traffic. 

This will improve ATC productivity, enhancing 

capacity and safety. [Figure 5-5]

4. Next generation network enabled weather 

(NNEW)— seventy percent of NAS delays are 

attributed to weather every year. The goal of NNEW 

is to cut weather-related delays at least in half. Tens 

of thousands of global weather observations and 

sensor reports from ground, airborne, and spacebased sources will fuse into a single national weather 

information system updated in real time. NNEW 

will provide a common weather picture across the 

NAS and enable better air transportation decisionmaking. [Figure 5-6]

5. NAS voice switch (NVS)—there are currently 

seventeen different voice switching systems in the 

NAS; some in use for more than twenty years. NVS 

will replace these systems with a single air/ground 

and ground/ground voice communications system. 

[Figure 5-7]

NextGen Existing Improvements

The goal of NextGen is to provide new capabilities that 

make air transportation safer and more reliable while 

improving the capacity of the NAS and reducing aviation’s 

impact on the environment. Below is a list of some of the 

capabilities for operational use that have already been 
5-4

Figure 5-4. System wide information management (SWIM)—an information management system that helps deliver high quality, timely 

data to improve the efficiency of the national airspace. 

Figure 5-5. Next generation data communications provides an additional means of two-way communication for ATC clearances, 

instructions, advisories, flight crew requests, and reports.

En Route Data

Surveillance Weather

Radar Data

Traffic Flow 

Management

Aeronautical

Information

Inter-Agency

Terminal

Data

SWIM

Core 

Services

Today

Existing systems communication 

structure

Enterprise Management

Secure access points for NAS systems 

and data sharing

Network

ARTCCs

ARTCSCC

Tower

TRACONs

VDL-2

VDL-2

User Flight 

Operations 

Control

Digital ATIS

Taxi Instructions

Departure Clearance

Optimized 

Descents

(TAPs/CDAs)

Fix

Time Based Metering

Clearances WX Reroutes

Trajectory Based Operations

High Performance Airspeed

ARTCCS

TRACONS

TOWERS
5-5

Figure 5-6. Next generation network enabled weather (NNEW) provides a common weather picture across the NAS.

Figure 5-8. ADS-B, is being used to provide ATC surveillance over the Gulf of Mexico. 

Figure 5-7. National airspace voice switch (NVS) will replace 

existing voice switching systems with single air/ground and ground/

ground voice communication systems. 

34

Flight planning Push back Final approach/landing

Domestic/oceanic cruise

Taxi

Takeoff

Descent

implemented through NextGen.

1. Starting in December 2009, the FAA began 

controlling air traffic over the Gulf of Mexico, an 

area of active airspace where surveillance was 

never before possible, using the satellite-based 

technology of ADS-B. [Figure 5-8] Having a real-time 

visual representation of aircraft flying over the Gulf 

of Mexico, where no radar coverage was available, 

means that ATC can safely and more efficiently 

separate air traffic. It also provides pilots with 

more safety benefits such as improved situational 

awareness (SA), new weather information, and 

additional voice communications. 

2. Initial operating capability was achieved for ADS-B 

at Louisville, Kentucky, where ADS-B was integrated 

into the Common Automated Radar Terminal 

System. 

3. Satellite-based technologies, including the Wide 

Area Augmentation System (WAAS), are improving 

access to runways at both large and small airports. 
5-6

Figure 5-9. Wide Area Augmentation System (WAAS).

GEO satellite

GEO satellite

GPS satellites

Wide-area reference station (WRS)

Wide-area master station (WMS)

Goose Bay

Gander

Nashua

Ronkonkoma

Leesburg

San Juan

Miami

Jacksonville

Hampton

Memphis

Oberlin Aurora

Houston

Merida

Mexico City

Puert Vallarta

San Jose Del Cabo

Palmdale

Honolulu

Cold Bay

Bethel

Anchorage

Fairbanks

Barrow

Kotzebue

Freemont

Auburn

Billings

Salt Lake

Longmont

Albuquerque

Winnipeg

Olathe

Iqaluit

Farmington

Juneau

Tapachula

Fort Worth

New WRSs

Ground uplink station

Legend

[Figure 5-9] Directions and maps have been published 

for more than 500 precision-like approaches 

enabled by WAAS. Localizer performance with 

vertical guidance (LPV) procedures improves 

access to airports in lower visibility conditions and 

where obstacles are present. These procedures 

are particularly valuable for smaller airports used 

by general aviation. There are now nearly 1,100 

LPV procedures available at runways where no 

instrument landing system (ILS) is present.

4. The Ground-Based Augmentation System (GBAS) has 

been approved for Category I operations and the 

first satellite-based system has been approved for 

this category of precision approach which enables 

instrument-based operations down to 200 feet 

above the surface even during reduced visibility. 

[Figure 5-10] GBAS was installed at Memphis, 

Tennessee and Newark, New Jersey airport in 2009. 

5. Multilateration, a ground-based surveillance 

technology, is being implemented to help improve 

runway access. The FAA installed and is now using 

wide area multilateration (WAM) systems to control 

air traffic in Juneau, Alaska, and at four airports in 

Colorado. This allows air traffic to be safely separated 

by five miles whereas before each aircraft had to clear 

the airspace around the airport before the next could 

enter. 

6. New runways at Chicago O’Hare, Washington 

Dulles, and Seattle-Tacoma Airports opened in 

November of 2008, which are now beginning to 

have a reduction in delays.

Benefits of NextGen

The implementation of NextGen will allow pilots and 

dispatchers to select their own direct flightpaths, rather 

than follow the existing Victor, Jet, and LF/MF airways. Each 

airplane will transmit and receive precise information about 

the time at which it and others will cross key points along 

their paths. Pilots and air traffic managers on the ground 

will have the same precise information transmitted via data 

communications.

Major demand and capacity imbalances will be worked 

collaboratively between FAA air traffic managers and flight 

operations. The increased scope, volume, and widespread 

distribution of information by SWIM will improve decision- 
5-7

Figure 5-10. Ground-Based Augmentation System (GBAS).

GPS satellites

Ranging sources

Differential corrections, integrity data and path definition

Omnidirectional VHF data broadcast (VDB) signal

GBAS reference receivers 

GBAS ground facility

Status information

Figure 5-11. NextGen improves airport surface movements, reduces 

spacing and separation requirements, and better manages the 

overall flows into and out of busy airports. 

making and let more civil aviation authorities participate. 

The impact of weather on flight operations will be reduced 

through the use of improved information sharing, new 

technology to sense and mitigate the impacts of the 

weather, and to improve weather forecasts and decisionmaking. Better forecasts, coupled with greater automation, 

will minimize airspace limitations and traffic restrictions.

The new procedures of NextGen will improve airport 

surface movements, reduce spacing and separation 

requirements, and better manage the overall flows into 

and out of busy airspace, as well as provide maximum use 

of busy airports. [Figure 5-11] Targeting NextGen at the 

whole of the NAS, rather than just the busiest airports, 

will uncover untapped capacity across the whole system. 

During busy traffic periods, NextGen will rely on aircraft to 

fly precise routes into and out of many airports to increase 

throughput. For more information on NextGen, visit www.

faa.gov/nextgen.

Head-Up Displays (HUD)

As aircraft became more sophisticated and electronic 

instrument landing systems (ILS) were developed in the 

1930s and 1940s, it was necessary while landing in poor 

weather for one pilot to monitor the instruments to keep 

the aircraft aligned with radio beams while the second pilot 

divided time between monitoring the instruments and 

the outside environment. The pilot monitoring reported 

the runway environment in sight and the flying pilot 

completed the approach visually. This is still the standard 

practice used for passenger carrying aircraft in commercial 

service while making ILS landings. As single-piloted aircraft 

became more complex, it became very difficult for pilots 

to focus on flying the aircraft while also monitoring a large 

number of navigation, flight, and systems instruments. To 

overcome this problem, the head-up display (HUD) was 

developed. By showing airspeed, altitude, heading, and 

aircraft attitude on the HUD glass, pilots were able to keep 

their eyes outside of the flight deck rather than have to 

continuously scan from outside to inside to view the flight 

instruments. [Figure 5-12] Collimators make the image on 

the glass appear to be far out in front of the aircraft so that 

the pilot need not change eye focus to view the relatively 

nearby HUD. Today’s head-up guidance systems (HGS) 

use holographic displays. [Figure 5-13] Everything from 

weapons status to approach information can be shown 

on current military and civilian HGS displays.
5-8

Figure 5-12. Head-up guidance system (HGS). 

Figure 5-13. HGS using a holographic display. 

Figure 5-14. A synthetic vision system (SVS) is an electronic means to 

display a synthetic vision image of the external scene topography to the 

flight crew to assist during takeoffs, landings, and en route operations. 

Figure 5-15. An aircraft on an approach equipped with a SVS.

160

140

100

80

60

10

10

11 4

7800

7600

7400

7200

20

00

75

220

240

Synthetic and Enhanced Vision Systems

Synthetic Vision System (SVS)

A synthetic vision system (SVS) is an electronic means 

to display a synthetic vision image of the external scene 

topography to the flight crew. [Figure 5-14] It is not a 

real-time image like that produced by an enhanced flight 

vision system (EFVS). Unlike EFVS, SVS requires a terrain 

and obstacle database, a precise navigation solution, and 

a display. The terrain image is based on the use of data 

from a digital elevation model (DEM) that is stored within 

the SVS. With SVS, the synthetic terrain/vision image is 

intended to enhance pilot awareness of spatial position 

relative to important features in all visibility conditions. 

This is particularly useful during critical phases of flight, 

such as takeoff, approach, and landing where important 

features such as terrain, obstacles, runways, and landmarks 

may be depicted on the SVS display. [Figure 5-15] During 

approach operations, the obvious advantages of SVS are 

that the digital terrain image remains on the pilot’s display 

regardless of how poor the visibility is outside. An SVS 

image can be displayed on either a head-down display or 

head-up display (HUD). Development efforts are currently 

underway that would combine SVS with a real-time sensor 

image produced by an EFVS. These systems will be known 

as Combined Vision Systems (CVS). 

Enhanced Flight Vision System (EFVS)

For an in-depth discussion regarding Enhanced Flight 

Vision Systems, please see Chapter 4, page 4-20.
5-9

Figure 5-16. Enhanced and synthetic vision displayed on primary 

flight displays. Figure 5-17. Installed flight bag.

Figure 5-18. Portable flight bag.

Developing Combined Technology 

The United States air transportation system is undergoing 

a transformation to accommodate a projected three-fold 

increase in air operations by 2025. Technological and 

systemic changes are being developed to significantly 

increase the capacity, safety, efficiency, and security for this 

Next Generation Air Transportation System (NextGen). One 

of the key capabilities envisioned to achieve these goals is 

the concept of equivalent visual operations (EVO), whereby 

visual flight rules (VFR) and operating procedures, such as 

separation assurance, are maintained independent of the 

actual weather conditions. One methodology by which the 

goal of EVO might be attainable is to create a virtual visual 

flight environment for the flight crew, independent of the 

actual outside weather and visibility conditions, through 

application of EV and synthetic vision (SV) technologies. 

[Figure 5-16]

Electronic Flight Bag (EFB) 

The electronic flight bag (EFB) is a system for pilots or 

crewmembers that provide a variety of electronic display, 

content manipulation, and calculation capabilities. 

Functions include, but are not limited to, aeronautical 

charts, documents, checklists, weight & balance, fuel 

calculations, moving maps, and logbooks. 

EFB systems may manage information for use in the 

cockpit, cabin, and/or in support of ground operations 

and planning. The use of an EFB is unique to each aircraft 

operator and, depending on the type of operation, EFB use 

may require an authorization for use from the FAA issued as 

either an operations specification (OpSpec), maintenance 

specification (MSpec), or letter of authorization (LOA).

EFBs can be portable [Figure 5-18] or installed [Figure 

5-19] in the aircraft. Portable EFBs may have a provision for 

securing in the cockpit for use during all phases of flight. 

The hardware device, whether it’s an installed avionics 

display or portable commercial-off-the-shelf (COTS) 

device, commonly referred to as a portable electronic 

device (PED), is not considered to be an EFB unless the 

hardware device hosts and actively displays either Type 

A or B software application(s). A non-inclusive list of Type 

A and B software application examples can be found in 

appendix 1 and 2 of FAA Advisory Circular (AC) 120-76. 

The purpose, technology, and functions for EFB use are 

rapidly evolving. New and advanced software applications 

and databases beyond traditional flight bag uses continue 

to be developed. The FAA has published and continues 

to update EFB policy and guidance to educate and assist 

aircraft operators interested in using or obtaining an EFB 

authorization as appropriate. The most current editions of 

the following FAA guidance and policy can be accessed 

from the FAA’s website (http://www.faa.gov) or FAA’s 

Flight Standards Information Management System (FSIMS 

http://fsims.faa.gov). 

•	 AC 120-76, Guidelines for the Certification,

Airworthiness, and Operational Use of Electronic 
5-10

Figure 5-27. Restricted airspace. 

Figure 5-28. Prohibited airspace. 

Figure 5-29. Military operations area (MOA). 

Figure 5-30. Warning area. 

Flight Bags;

•	 AC 91-78, Use of Class 1 or Class 2 Electronic Flight

Bag (EFB);

•	 AC 20-173, Installation of Electronic Flight Bag

Components;

•	 FAA Order 8900.1 Volume 4, Chapter 15, Section 1,

Electronic Flight Bag authorization for use; and

•	 FAA Order 8900.1 Volume 3, Chapter 18, Section 3,

Part A Operations Specifications - General 

Access to Special Use Airspace 

Special use airspace consists of airspace of defined 

dimensions identified by an area on the surface of the earth 

wherein activities must be confined because of their nature, 

or wherein limitations are imposed upon aircraft operations 

that are not a part of those activities, or both. Special use 

airspace includes: restricted airspace, prohibited airspace, 

Military Operations Areas (MOA), warning areas, alert areas, 

temporary flight restriction (TFR), and controlled firing 

areas (CFAs). [Figures 5-27 through 5-32] Prohibited and 

restricted areas are regulatory special use airspace and 

are established in 14 CFR Part 73 through the rulemaking 

process. Warning areas, MOAs, alert areas, and CFAs are 

non-regulatory special use airspace. All special use airspace 

descriptions (except CFAs) are contained in FAA Order

7400.8, Special Use Airspace, and are charted on IFR or 

visual charts and include the hours of operation, altitudes, 

and the controlling agency. [Figure 5-33]

The vertical limits of special use airspace are measured 

by designated altitude floors and ceilings expressed as 

flight levels or as feet above mean sea level (MSL). Unless 

otherwise specified, the word “to” (an altitude or flight level) 

means “to and including” (that altitude or flight level). The 

horizontal limits of special use airspace are measured by 
5-11

Figure 5-31. Alert area. 

Figure 5-32. Temporary flight restriction (TFR). 

boundaries described by geographic coordinates or other 

appropriate references that clearly define their perimeter. 

The period of time during which a designation of special 

use airspace is in effect is stated in the designation.

Civilians Using Special Use Airspace

The FAA and the Department of Defense (DOD) work 

together to maximize the use of special use airspace 

by opening such areas to civilian traffic when they are 

not being used by the military. The military airspace 

management system (MAMS) keeps an extensive database 

of information on the historical use of special use airspace, 

as well as schedules describing when each area is expected 

to be active. MAMS transmits the data to the special use 

airspace management system (SAMS), an FAA program 

that provides current and scheduled status information 

on special use airspace to civilian users. The two systems 

work together to ensure that the FAA and system users 

have current information on a daily basis. This information 

is available 24 hours a day at the following link: http://sua.

faa.gov. The website merges information for both special 

use airspace and TFR making it a single comprehensive 

source to review airspace closure information.

The website contains two tabbed pages, List and Map, that 

display the scheduling and Notice to Airmen (NOTAM) data 

for SUAs, military training routes (MTRs), and TFRs. [Figure 

5-34] By default, the List tabbed page displays all airspace 

types, and the Map tabbed page displays all airspace types 

apart from MTRs and ATC Assigned Airspaces (ATCAAs). 

Both the List and Map tabbed pages can be filtered to 

display specific data for an airspace name, type, or group. 

Groups include SUA, MTR, or TFR. The Map tabbed page 

provides a graphical depiction of scheduled airspaces 

that may be customized using a fly-out menu of map 

display options. This tabbed page also contains look-up 

functionality that allows a user to locate one or more 

airports within the map. [Figures 5-35 through 5-38]

Additional navigation features are included which allows 

the user to pan in any direction by dragging the cursor 

within the map. A permalink feature is also available that 

enables a user to bookmark a customized set of map layers 

that can easily be added to their Internet browser favorites 

list. Once a specific set of customized map layers has been 

bookmarked, a user may open that customized map display 

using the favorites option within their browser menu. The

List tabbed page allows a user to view all SUA and MTR 

scheduling data and NOTAM text for a TFR. This text may 

be viewed for each NOTAM ID by expanding the NOTAM 

text section within the List grid or clicking the NOTAM ID 

to open a TFR Details page. The TFR Details page displays 

NOTAM text in a form layout for easy reading and includes 

a mapped image and sectional navigation map if available 

for the TFR.
5-12

Figure 5-33. Special use airspace charted on an aeronautical chart.

U.S. P–PROHIBITED, R–RESTRICTED, W–WARNING, A–ALERT, MOA–MILITARY OPERATIONS AREA 

Unless otherwise noted are MSL and in feet. 

Time is local. “TO” an altitude means “To and including.”

FL – Flight Level

NO A/G – No air to ground communications. 

Contact nearest FSS for information.

† Other times by NOTAM.

NOTAM – Use of this term in Restricted Areas 

indicates FAA and DoD NOTAM systems. 

Use of this term in all other Special Use areas indicates 

the DoD NOTAM system.

SPECIAL USE AIRSPACE ON JACKSONVILLE SECTIONAL CHART

TO BUT NOT

INCL 3,000

TO BUT NOT 

INCL 23,000

TO 7,000

TO 5,000

TO BUT NOT

INCL 1,800

TO 14,000

TO FL 230 

P-50

R-2903 A

R-2903 C

R-2903 D

R-2904 A

R-2906

R-2907 A

CONTINUOUS

INTERMITTENT

0700-1900 TUE-SUN

†24 HRS IN ADVANCE

INTERMITTENT

0700-1900 TUE-SUN

†24 HRS IN ADVANCE

INTERMITTENT

0700-1900 TUE-SUN

†24 HRS IN ADVANCE

0800-1700 (APR-AUG)

0800-1700 SAT-SUN (SEP-MAR)

†24 HRS IN ADVANCE

INTERMITTENT

0500-0100

†6 HRS IN ADVANCE

INTERMITTENT

0500-0100

†6 HRS IN ADVANCE

NO A/G

JACKSONVILLE CNTR

JACKSONVILLE TRACON

JACKSONVILLE TRACON

JACKSONVILLE TRACON

JACKSONVILLE TRACON

JACKSONVILLE CNTR

NUMBER ALTITUDE TIME OF USE CONTROLLING AGENCY/

CONTACT FACILITY FREQUENCIES
5-13

Figure 5-34. FAA website providing information for both special use airspace and temporary flight restrictions. 
5-14

Figure 5-35. Center locations and information available to pilots through the FAA website.
5-15

Figure 5-36. State information available to pilots through the FAA website.
5-16

Figure 5-37. Map layer options and information available to pilots through the FAA website.
5-17

Figure 5-38. Airport information available to pilots through the FAA website.
5-18
6-1

Introduction 

Area Navigation (RNAV) systems, aeronautical applications, 

and functions that depend on databases are widespread. 

[Figure 6-1] Since the 1970s, installed flight systems 

have relied on airborne navigation databases to support 

their intended functions, such as navigation data used 

to facilitate the presentation of flight information to the 

flight crew and understanding and better visualization 

of the governing aeronautical flight charts. With the 

overwhelming upgrades to navigation systems and fully 

integrated flight management systems (FMS) that are now 

installed in almost all corporate and commercial aircraft, 

the need for reliable and consistent airborne navigation 

databases is more important than ever. 

Airborne Navigation Databases

Chapter 6
6-2

Figure 6-1. Area navigation (RNAV) receivers.

The capabilities of airborne navigation databases depend 

largely on the way they are implemented by the avionics 

manufacturers. They can provide data about a large 

variety of locations, routes, and airspace segments for use 

by many different types of RNAV equipment. Databases 

can provide pilots with information regarding airports, 

air traffic control (ATC) frequencies, runways, and special 

use airspace. Without airborne navigation databases, 

RNAV would be extremely limited. In order to understand 

the capabilities and limitations of airborne navigation 

databases, pilots must understand the way databases 

are compiled and revised by the database provider and 

processed by the avionics manufacturer. manufacturer. 

Vital to this discussion is understanding of the regulations 

guiding database maintenance and use.

There are many different types of RNAV systems certified 

for instrument flight rules (IFR) use in the National Airspace 

System (NAS). The two most prevalent types are GPS and 

the multisensory FMS. [Figure 6-2] A modern GPS unit 

accurately provides the pilot with the aircraft’s present 

position; however, it must use an airborne navigation 

database to determine its direction or distance from 

another location. The database provides the GPS with 
6-3

Figure 6-2. GPS with a flight route on display. 

RNG

PULL SCAN

PUSH ON

BRT

PROC CRSR

MSG OBS ALT NRST D CLR ENT

MENU

DTK

TK

. nm

LEG

APT 1 VOR NDB INT USR ACT NAV FPL SET AUX

A B C D

E F G H

I J K L

M N O P

Q R S T

U V W X

Y Z SPC BKSP

PFD MFD

NAV COM

PFD MENU

FPL PROC

SEL CLR ENT

DFLT MAP

SOFTKEY SELECT

EMERG

PUSH CRSR/PUSH 1-2

FMS/

NAV-COM

PUSH PAN

RANGE

− +

1 2 3

4 5 6

7 8 9

− 0 +

The display allows you to view information stored in the FMS.

Controls such as 

buttons and knobs 

allow you to make 

entries into the FMS.

Figure 6-3. FMS display.

BACK EXEC XPND

Modify

Wpt

Arwy

Modified

KSQL 027

KSQL

SUNOL 21.7

027 21.7

No Active Leg

DIST

BRG 060° 21.7

discontinuity

BRG --- ---

FPL

n

m

n

m

GPS ENR

FLAGGED

119.000

121.600

114.10

116.00

1200

A 

C 

T

A 

C 

T

S 

B 

Y

S 

B 

Y

S 

B 

Y

--.- vor

BACK

V195

V301

V334

 SUNOL

 V195 ECA

50nm

ECA

SUNOL

GPS ENR FPL

N

FLAGGED

119.000

121.600

114.10

116.00

1200

A 

C 

T

A 

C 

T

S 

B 

Y

S 

B 

Y

S 

B 

Y

--.- vor

BACK EXEC XPND

Modify Modified

KSQL

SUNOL 21.7

V195 ECA:

TRACY 40.0

SHARR 49.6

ECA 55.0

No Active Leg

DIST

BRG 060° 21.7

BRG 060° 18.3

BRG 060° 9.6

BRG 049° 5.4

FPL

n

m

n

m

n

m

n

m

GPS ENR

FLAGGED

119.000

121.600

114.10

116.00

1200

A 

C 

T

A 

C 

T

S 

B 

Y

S 

B 

Y

S 

B 

Y

--.- vor

This FMS allows you to insert 

an entire airway into your route.

The software performs a 

database search for all of the 

airways, causing all waypoints 

along the airway to be inserted 

into the route.

The navigation database looks up

all of the airways that connect to

the previous waypoint in the route.

position information for navigation fixes so it may perform 

the required geodetic calculations to determine the 

appropriate tracks, headings, and distances to be flown. 

[Figure 6-3]

Modern FMS are capable of a large number of functions 

including basic en route navigation, complex departure 

and arrival navigation, fuel planning, and precise vertical 

navigation. Unlike stand-alone navigation systems, most 

FMS use several navigation inputs. Typically, they formulate 

the aircraft’s current position using a combination of 

conventional distance measuring equipment (DME) signals, 

inertial navigation systems (INS), GPS receivers, or other 

RNAV devices. Like stand-alone navigation avionics, they 

rely heavily on airborne navigation databases to provide 

the information needed to perform their numerous 

functions.

Airborne Navigation Database 

Standardization

Beginning in the 1970s, the requirement for airborne 
6-4

navigation databases became more critical. In 1973, 

National Airlines installed the Collins ANS-70 and AINS70 RNAV systems in their DC-10 fleet, which marked the 

first commercial use of avionics that required navigation 

databases. A short time later, Delta Air Lines implemented 

the use of an ARMA Corporation RNAV system that also 

used a navigation database. Although the type of data 

stored in the two systems was basically identical, the 

designers created the databases to solve the individual 

problems of each system, which meant that they were not 

interchangeable. As the implementation of RNAV systems 

expanded, a world standard for airborne navigation 

databases was needed.

In 1973, Aeronautical Radio, Inc. (ARINC) sponsored the 

formation of a committee to standardize aeronautical 

databases. In 1975, the committee published the first 

standard, ARINC Specification 424, which has remained the 

worldwide accepted format for transmission of navigation 

databases.

ARINC 424

ARINC 424 is the air transport industry’s recommended 

standard for the preparation and transmission of data for 

the assembly of airborne system navigation databases. The 

data is intended for merging with the aircraft navigation 

system software to provide a source of navigation 

reference. Each subsequent version of ARINC 424 

Specification provides additional capability for navigation 

systems to utilize. Merging of ARINC 424 data with each 

manufacturer’s system software is unique and ARINC 424 

leg types provide vertical guidance and ground track for 

a specific flight procedure. These leg types must provide 

repeatable flight tracks for the procedure design. The 

navigation database leg type is the path and terminator 

concept.

ARINC 424 Specification describes 23 leg types by their path 

and terminator. The path describes how the aircraft gets to 

the terminator by flying direct (a heading, a track, a course, 

etc.). The terminator is the event or condition that causes 

the navigation computer system to switch to the next leg (a 

fix, an altitude, an intercept, etc.). When a flight procedure 

instructs the pilot to fly runway heading to 2000 feet then 

direct to a fix, this is the path and terminator concept. The 

path is the heading and the terminator is 2000 feet. The 

next leg is then automatically sequenced. A series of leg 

types are coded into a navigation database to make a flight 

procedure. The navigation database allows an FMS or GPS 

navigator to create a continuous display of navigational 

data, thus enabling an aircraft to be flown along a specific 

route. Vertical navigation can also be coded.

The data included in an airborne navigation database is 

organized into ARINC 424 records. These records are strings 

of characters that make up complex descriptions of each 

navigation entity. ARINC records can be sorted into four 

general groups: fix records, simple route records, complex 

route records, and miscellaneous records. Although it is not 

important for pilots to have in-depth knowledge of all the 

fields contained in the ARINC 424 records, pilots should be 

aware of the types of records contained in the navigation 

database and their general content.

Fix Records

Database records that describe specific locations on the 

face of the earth can be considered fix records. Navigational 

aids (NAVAIDs), waypoints, intersections, and airports are 

all examples of this type of record. These records can be 

used directly by avionics systems and can be included as 

parts of more complex records like airways or approaches.

Another concept pilots should understand relates to how 

aircraft make turns over navigation fixes. Fixes can be 

designated as fly-over or fly-by, depending on how they 

are used in a specific route. [Figure 6-4] Under certain 

circumstances, a navigation fix is designated as fly-over. 

This simply means that the aircraft must actually pass 

directly over the fix before initiating a turn to a new course. 

Conversely, a fix may be designated fly-by, allowing an 

aircraft’s navigation system to use its turn anticipation 

feature, which ensures that the proper radius of turn is 

commanded to avoid overshooting the new course. Some 

RNAV systems are not programmed to fully use this feature. 

It is important to remember a fix can be coded as fly-over 

and fly-by in the same procedure, depending on how the 

fix is used (i.e., holding at an initial approach fix). RNAV or 

GPS stand-alone IAPs are flown using data pertaining to 

the particular IAP obtained from an onboard database 

to include the sequence of all waypoints used for the 

approach and missed approach, except that step down 

waypoints may not be included in some TSO-C129 receiver 

databases. Included in the database, in most receivers, is 

coding that informs the navigation system of which WPs 

are fly-over or fly-by. The navigation system may provide 

guidance appropriately to include leading the turn prior 

to a fly-by waypoint; or causing over flight of a fly-over 

waypoint. Where the navigation system does not provide 

such guidance, the pilot must accomplish the turn lead or 

waypoint over flight manually. Chart symbology for the flyby waypoint provides pilot awareness of expected actions.
6-5

Figure 6-4. Fly-by-waypoints and fly-over-waypoints.

Flight plan path

Airplane track

Waypoint

Waypoint

Fly-by

Fly-over

Simple Route Records

Route records are those that describe a flightpath instead 

of a fixed position. Simple route records contain strings 

of fix records and information pertaining to how the fixes 

should be used by the navigation avionics.

A Victor Airway, for example, is described in the database by 

a series of en route airway records that contain the names 

of fixes in the airway and information about how those 

fixes make up the airway.

Complex Route Records

Complex route records include those strings of fixes that 

describe complex flightpaths like standard instrument 

departures (SIDs), standard terminal arrival routes (STARs), 

and instrument approach procedures (IAPs). Like simple 

routes, these records contain the names of fixes to be 

used in the route, as well as instructions on how the route 

is flown.

Miscellaneous Records

There are several other types of information that is coded 

into airborne navigation databases, most of which deal 

with airspace or communications. The receiver may contain 

additional information, such as restricted airspace, airport 

minimum safe altitudes, and grid minimum off route 

altitudes (MORAs).

Path and Terminator Concept

The path and terminator concept is a means to permit 

coding of terminal area procedures, SIDs, STARs, and 

approach procedures. Simply put, a textual description of 

a route or a terminal procedure is translated into a format 

that is useable in RNAV systems. One of the most important 

concepts for pilots to learn regarding the limitations of 

RNAV equipment has to do with the way these systems 

deal with the path and terminator field included in complex 

route records.

The first RNAV systems were capable of only one type of 

navigation; they could fly directly to a fix. This was not a 

problem when operating in the en route environment 

in which airways are mostly made up of direct routes 

between fixes. The early approaches for RNAV did not 

present problems for these systems and the databases 

they used because they consisted mainly of DME/DME 

overlay approaches flown only direct point-to-point 

navigation. The desire for RNAV equipment to have the 

ability to follow more complicated flightpaths necessitated 

the development of the path and terminator field that is 

included in complex route records.
6-6

Figure 6-5. Initial fix.

Figure 6-6. Track to a fix leg type.

TF LEG

Figure 6-7. Constant radius arc or RF leg.

Next

segment

RF LEG

ARC

CENTER

FIX

Previous

segment

Figure 6-8. Course to a fix or CF leg.

CF LEG

080°

Course is flown making adjustment for wind

Figure 6-9. Direct to a fix or DF leg.

DF LEG

Unspecified position

Figure 6-10. Fix to an altitude or FA leg.

FA LEG

080°

Unspecified position

8,000'

FA leg is flown making adjustment for wind

Path and Terminator Legs

There are currently 23 different leg types, or path and 

terminators that have been created in the ARINC 424 

standard that enable RNAV systems to follow the complex 

paths that make up instrument departures, arrivals, and 

approaches. They describe to navigation avionics a path 

to be followed and the criteria that must be met before 

the path concludes and the next path begins. Although 

there are 23 leg types available, none of the manufactured 

database equipment is capable of using all of the leg types. 

Pilots must continue to monitor procedures for accuracy 

and not rely solely on the information that the database 

is showing. If the RNAV system does not have the leg type 

demanded by procedures, data packers have to select one 

or a combination of available lleg types to give the best 

approximation, which can result in an incorrect execution 

of the procedure. Below is a list of the 23 leg types and 

their uses that may or may not be used by all databases. 

•	 Initial fix or IF leg—defines a database fix as a point

in space and is only required to define the beginning 

of a route or procedure. [Figure 6-5] 

•	 Track to a fix or TF leg—defines a great circle track

over the ground between two known database 

fixes and the preferred method for specification of 

straight legs (course or heading can be mentioned 

on charts but designer should ensure TF leg is used 
6-7

Figure 6-11. Track from a fix from a distance or FC leg.

FC LEG

9 NM

080°

Figure 6-12. Track from a fix to a DME distance or FD leg.

FD LEG

D 10

080°

Figure 6-13. From a fix to a manual termination or FM leg.

FM LEG

080°

Manual

termination

FM leg is flown making adjustment for wind

Figure 6-14. Course to an altitude or CA leg.

CA LEG

090°

Unspecified position

9,000'

Course is flown making adjustment for wind

Figure 6-15. Course to a DME distance of CD leg.

CD LEG

090°

D 10

Figure 6-16. Course to an intercept or CI leg.

CI LEG

090°

070°

Next leg

Figure 6-17. Course to a radial termination or CR leg.

CR LEG

120°

170°

for coding). [Figure 6-6]

•	 Constant radius arc or RF leg—defines a constant

radius turn between two databases fixes, lines 

tangent to the arc, and a center fix. [Figure 6-7] 

•	 Course to a fix or CF leg—defines a specified course

to a specific database fix. Whenever possible, TF legs 

should be used instead of CF legs to avoid magnetic 

variation issues. [Figure 6-8]

•	 Directtoa fixorDF leg—defines anunspecifiedtrack

starting from an undefined position to a specified 

fix. [Figure 6-9]

•	 Fix to an altitude or FAleg—defines a specified track

over the ground from a database fix to a specified 

altitude at an unspecified position. [Figure 6-10]

•	 Track from a fix from a distance or FC leg—defines

a specified track over the ground from a database 

fix for a specific distance. [Figure 6-11]

•	 Track from a fix to a distance measuring equipment

(DME) distance or FD leg—defines a specified track 

over the ground from a database fix to a specific 

DME distance that is from a specific database DME 
6-8

Figure 6-18. Arc to a fix or AF leg.

Figure 6-21. Heading to an intercept or VI leg.

Figure 6-22. Heading to a manual termination or VM leg.

Figure 6-23. Heading to a radial termination or VR leg.

Boundary radial

245°

D10

AF LEG

VI LEG

090°

070°

Next leg

VM LEG

Manual termination 070°

No correction made for wind

VR LEG

120°

170°

Figure 6-19. Heading to an altitude termination or VA leg.

Figure 6-20. Heading to a DME distance termination or VD leg.

VA LEG

Unspecified position

8,000'

090°

No correction made for wind

VD LEG

090°

D 10

NAVAID. [Figure 6-12]

•	 From a fix to a manual termination or FM leg—

defines a specified track over the ground from a 

database fix until manual termination of the leg. 

[Figure 6-13]

•	 Course to an altitude or CA leg—defines a specified

course to a specific altitude at an unspecified 

position. [Figure 6-14]

•	 Course to a DME distance or CD leg—defines a

specified course to a specific DME distance that is 

from a specific database DME NAVAID. [Figure 6-15]

•	 Course to an intercept or CI leg—defines a specified

course to intercept a subsequent leg. [Figure 6-16]

•	 Course to a radial termination or CR leg—defines a

course to a specified radial from a specific database 

VOR NAVAID. [Figure 6-17]

•	 Arc toa fixorAF leg—defines a trackovertheground

at a specified constant distance from a database 

DME NAVAID. [Figure 6-18]

•	 Heading to an altitude termination or VA leg—

defines a specified heading to a specific altitude 

termination at an unspecified position. [Figure 6-19]
6-9

Figure 6-24. Procedure turn or PI leg.

Figure 6-25. Racetrack course reversal or HA, HF, and HM leg.

PI

063°

018°

HA, HF, HM

076°

Previous leg

HA - Terminates at an altitude

HF - Terminates at the fix after one orbit

HM - Manually terminated

•	 Heading to a DME distance termination or VD

leg—defines a specified heading terminating at a 

specified DME distance from a specific database 

DME NAVAID. [Figure 6-20]

•	 Heading to an intercept or VI leg—defines a

specified heading to intercept the subsequent leg 

at an unspecified position. [Figure 6-21]

•	 Heading to a manual termination or VM leg—

defines a specified heading until a manual 

termination. [Figure 6-22]

•	 Heading to a radialtermination orVR leg—defines a

specified heading to a specified radial from a specific 

database VOR NAVAID. [Figure 6-23]

•	 Procedure turn or PI leg—defines a course reversal

starting at a specific database fix and includes 

outbound leg followed by a left or right turn and 

180° course reversal to intercept the next leg. [Figure 

6-24]

•	 Racetrack course reversal or altitude termination

(HA), single circuit terminating at the fix (base turn)

(HF), or manual termination (HM) leg types—define 

racetrack pattern or course reversals at a specified 

database fix. [Figure 6-25]

The GRAND JUNCTION FIVE DEPARTURE for Grand Junction 

Regional in Grand Junction, Colorado, provides a good 

example of different types of path and terminator legs 

used. [Figure 6-26] When this procedure is coded into the 

navigation database, the person entering the data into the 

records must identify the individual legs of the flightpath 

and then determine which type of terminator should be 

used.

The first leg of the departure for Runway 11 is a climb 

via runway heading to 6,000 feet mean sea level (MSL) 

and then a climbing right turn direct to a fix. When this is 

entered into the database, a heading to an altitude (VA) 

value must be entered into the record’s path and terminator 

field for the first leg of the departure route. This path and 

terminator tells the avionics to provide course guidance 

based on heading, until the aircraft reaches 6,000 feet, 

and then the system begins providing course guidance 

for the next leg. After reaching 6,000 feet, the procedure 

calls for a right turn direct to the Grand Junction (JNC) 

VORTAC. This leg is coded into the database using the path 

and terminator direct to a fix (DF) value, which defines an 

unspecified track starting from an undefined position to a 

specific database fix. After reaching

Another commonly used path and terminator value is 

heading to a radial (VR) which is shown in Figure 6-27 

using the CHANNEL ONE DEPARTURE procedure for Santa 

Ana, California. The first leg of the runway 19L/R procedure 

requires a climb on runway heading until crossing the I-SNA 

1 DME fix or the SLI R-118, this leg must be coded into the 

database using the VR value in the Path and Terminator 

field. After crossing the I-SNA 1 DME fix or the SLI R-118, the 

avionics should cycle to the next leg of the procedure that 

in this case, is a climb on a heading of 175° until crossing SLI 

R-132. This leg is also coded with a VR Path and Terminator. 

The next leg of the procedure consists of a heading of 200° 

until intercepting the SXC R-084. In order for the avionics to 

correctly process this leg, the database record must include 

the heading to an intercept (VI) value in the Path and 

Terminator field. This value directs the avionics to follow 

a specified heading to intercept the subsequent leg at an 

unspecified position.

The path and terminator concept is a very important part 

of airborne navigation database coding. In general, it is not 

necessary for pilots to have an in-depth knowledge of the 

ARINC coding standards; however, pilots should be familiar 

with the concepts related to coding in order to understand 

the limitations of specific RNAV systems that use databases.

Path and Terminator Limitations

How a specific RNAV system deals with Path and 

Terminators is of great importance to pilots operating 
6-10

Figure 6-26. Grand Junction Five Departure.

NOT FOR NAVIGATION

SW-1, 18 NO

V 2010 to 16 DEC 2010

SW-1, 18 NO

V 2010 to 16 DEC 2010
6-11

Figure 6-27. Channel One Departure.

NOT FOR NAVIGATION
6-12

Figure 6-28. ILS or LOC/DME RWY 3 in Durango, Colorado.

NOT FOR NAVIGATION

SW-1, 18 NO

V 2010 to 16 DEC 2010

SW-1, 18 NO

V 2010 to 16 DEC 2010
6-13

Figure 6-29. Naming conventions of three different systems for the VOR 34 Approach.

EUGA <VOR 34 >APR

IAF / TRAN: D130NI

F

with airborne navigation databases. Some early RNAV 

systems may ignore this field completely. The ILS or LOC/ 

DME RWY 3 approach at Durango, Colorado, provides an 

example of problems that may arise from the lack of path 

and terminator capability in RNAV systems. Although 

approaches of this type are authorized only for sufficiently 

equipped RNAV systems, it is possible that a pilot may elect 

to fly the approach with conventional navigation, and then 

reengage RNAV during a missed approach. If this missed 

approach is flown using an RNAV system that does not use 

Path and terminator values or the wrong leg types, then 

the system will most likely ignore the first two legs of the 

procedure. This will cause the RNAV equipment to direct 

the pilot to make an immediate turn toward the Durango 

VOR instead of flying the series of headings that terminate 

at specific altitudes as dictated by the approach procedure. 

[Figure 6-28] Pilots must be aware of their individual 

systems Path and Terminator handling characteristics 

and always review the manufacturer’s documentation to 

familiarize themselves with the capabilities of the RNAV 

equipment they are operating. Pilots should be aware that

 some RNAV equipment was designed without the fly-over 

capability which can cause problems for pilots attempting 

to use this equipment to fly complex flightpaths in the 

departure, arrival, or approach environments.

Role of the Database Provider

Compiling and maintaining a worldwide airborne 

navigation database is a large and complex job. Within the 

United States, the FAA sources give the database providers 

information, in many different formats, which must be 

analyzed, edited, and processed before it can be coded 

into the database. In some cases, data from outside the 

United States must be translated into English so it may be 

analyzed and entered into the database. Once the data is 

coded, it must be continually updated and maintained.

Once the FAA notifies the database provider that a change 

is necessary, the update process begins. The change is 

incorporated into a 28-day airborne database revision cycle 

based on its assigned priority. If the information does not 

reach the coding phase prior to its cutoff date (the date that 

new aeronautical information can no longer be included 

in the next update), it is held out of revision until the next 

cycle. The cutoff date for aeronautical databases is typically 

21 days prior to the effective date of the revision.

The integrity of the data is ensured through a process called 

cyclic redundancy check (CRC). A CRC is an error detection 

algorithm capable of detecting small bit-level changes in 

a block of data. The CRC algorithm treats a data block as 

a single, large binary value. The data block is divided by a 

fixed binary number called a generator polynomial whose 

form and magnitude is determined based on the level of 

integrity desired. The remainder of the division is the CRC 

value for the data block. This value is stored and transmitted 

with the corresponding data block. The integrity of the 

data is checked by reapplying the CRC algorithm prior to 

distribution.

Role of the Avionics Manufacturer

When avionics manufacturers develop a piece of 

equipment that requires an airborne navigation database, 
6-14

Figure 6-30. Database rolls.

Database Providers

• Collect the data

• Format per ARINC 424

• Revise and maintain database

Avionics Manufacturers

Decide on:

• Information to be included

• How information will be processed

• User interface

Pilots (End Users)

• Ensure currency

• Execute updates

• Responsible for working knowledge of avionics using

 database

they typically form an agreement with a database provider 

to supply the database for that new avionics platform. It 

is up to the manufacturer to determine what information 

to include in the database for their system. In some cases, 

the navigation data provider has to significantly reduce the 

number of records in the database to accommodate the 

storage capacity of the manufacturer’s new product, which 

means that the database may not contain all procedures.

Another important fact to remember is that although there 

are standard naming conventions included in the ARINC 

424 specification, each manufacturer determines how 

the names of fixes and procedures are displayed to the 

pilot. This means that although the database may specify 

the approach identifier field for the VOR/DME Runway 

34 approach at Eugene Mahlon Sweet Airport (KEUG) in 

Eugene, Oregon, as “V34,” different avionics platforms 

may display the identifier in any way the manufacturer 

deems appropriate. For example, a GPS produced by one 

manufacturer might display the approach as “VOR 34,” 

whereas another might refer to the approach as “VOR/DME 

34,” and an FMS produced by another manufacturer may 

refer to it as “VOR34.” [Figure 6-29]

These differences can cause visual inconsistencies between 

chart and GPS displays, as well as confusion with approach 

clearances and other ATC instructions for pilots unfamiliar 

with specific manufacturer’s naming conventions. The 

manufacturer determines the capabilities and limitations 

of an RNAV system based on the decisions that it makes 

regarding that system’s processing of the airborne 

navigation database.

Users Role

Like paper charts, airborne navigation databases are 

subject to revision. According to Title 14 of the Code of 

Federal Regulations (14 CFR) Part 91, section 91.503, the 

end user (operator) is ultimately responsible for ensuring 

that data meets the quality requirements for its intended 

application. Updating data in an aeronautical database is 

considered to be maintenance and all Part 91 operators 

may update databases in accordance with 14 CFR Part 91, 

section 43.3(g). Parts 121, 125, and 135 operators must 

update databases in accordance with their approved 

maintenance program. For Part 135 helicopter operators, 

this includes maintenance by the pilot in accordance with 

14 CFR Part 43, section 43.3(h).

Pilots using the databases are ultimately responsible for 

ensuring that the database they are operating with is 

current. This includes checking Notices to Airmen (NOTAM)-

type information concerning errors that may be supplied 

by the avionics manufacturer or the database supplier. The 

database user is responsible for learning how the specific 

navigation equipment handles the navigation database. 

The manufacturer’s documentation is the pilot’s best source 

of information regarding the capabilities and limitations of 

a specific database. [Figure 6-30]

Operational Limitations of Airborne 

Navigation Databases

Understanding the capabilities and limitations of the 

navigation systems installed in an aircraft is one of the 

pilot’s biggest concerns for IFR flight. Considering the vast 

number of RNAV systems and pilot interfaces available 

today, it is critical that pilots and flight crews be familiar 

with the manufacturer’s operating manual for each RNAV 

system they operate and achieve and retain proficiency 

operating those systems in the IFR environment.

Most professional and general aviation pilots are familiar 

with the possible human factors issues related to flightdeck 

automation. It is particularly important to consider those 

issues when using airborne navigation databases. Although 

modern avionics can provide precise guidance throughout 

all phases of flight, including complex departures and 

arrivals, not all systems have the same capabilities.

RNAV equipment installed in some aircraft is limited to 

direct route point-to-point navigation. Therefore, it is 

very important for pilots to familiarize themselves with 

the capabilities of their systems through review of the 

manufacturer documentation. Most modern RNAV systems 

are contained within an integrated avionics system that 

receives input from several different navigation and aircraft 

system sensors. These integrated systems provide so much 
6-15

information that pilots may sometimes fail to recognize 

errors in navigation caused by database discrepancies or 

misuse. Pilots must constantly ensure that the data they 

enter into their avionics is accurate and current. Once 

the transition to RNAV is made during a flight, pilots and 

flight crews must always be capable and ready to revert to 

conventional means of navigation if problems arise.

Closed Indefinitely Airports

Some US airports have been closed for up to several years, 

with little or no chance that they will ever reopen; yet their 

“indefinite” closure status – as opposed to permanent or 

UFN closure, or abandonment – causes them to continue 

to appear on both VFR and IFR charts and in airborne 

navigation databases; and their instrument approach 

procedures, if any, continue to be included – and still 

appear to be valid – in the paper and electronic versions 

of the United States Terminal Procedures Publication (TPP) 

charts. Airpark South, 2K2, at Ozark, Missouri, is a case in 

point.

Even though this airport has been closed going on two 

years and, due to industrial and residential development 

surrounding it, likely will never be reopened, the airport 

is nonetheless still charted in a way that could easily 

lead a pilot to believe that it is still open and operating. 

Even the current US Low Altitude En route chart displays 

a blue symbol for this airport, indicating that it still has 

a Department of Defense (DOD) approved instrument 

approach procedure available for use.

Aircrews need to use caution when selecting an airport 

in a cautionary or emergency situation, especially if the 

airport was not previously analyzed suitable for diversion 

during preflight. Aircrews could assume, based on charts 

and their FMS database, the airport is suitable and perhaps 

the only available diversionary or emergency option. The 

airport however, could be closed and hazardous even for 

emergency use. In these situations, Air Traffic Control may 

be queried for the airport’s status. 

Storage Limitations

As the data in a worldwide database grows, the required 

data storage space increases. Over the years that panelmounted GPS and FMSs have developed, the size of the 

commercially available airborne navigation databases has 

grown exponentially.

Some manufacturer’s systems have kept up with this 

growth and some have not. Many of the limitations of 

older RNAV systems are a direct result of limited data 

storage capacity. For this reason, avionics manufacturers 

must make decisions regarding which types of procedures 

will be included with their system. For instance, older GPS 

units rarely include all of the waypoints that are coded into 

master databases. Even some modern FMS equipment, 

which typically have much larger storage capacity, do not 

include all of the data that is available from the database 

producers. The manufacturers often choose not to include 

certain types of data that they think is of low importance 

to the usability of the unit. For example, manufacturers 

of FMS used in large airplanes may elect not to include 

airports where the longest runway is less than 3,000 feet 

or to include all the procedures for an airport.

Manufacturers of RNAV equipment can reduce the size of 

the data storage required in their avionics by limiting the 

geographic area the database covers. Like paper charts, the 

amount of data that needs to be carried with the aircraft is 

directly related to the size of the coverage area. Depending 

on the data storage that is available, this means that the 

larger the required coverage area, the less detailed the 

database can be.

Again, due to the wide range of possible storage capacities, 

and the number of different manufacturers and product 

lines, the manufacturer’s documentation is the pilot’s best 

source of information regarding limitations caused by 

storage capacity of RNAV avionics.

Charting/Database Inconsistencies

It is important for pilots to remember that many 

inconsistencies may exist between aeronautical charts 

and airborne navigation databases. Since there are so 

many sources of information included in the production 

of these materials, and the data is manipulated by several 

different organizations before it is eventually displayed 

on RNAV equipment, the possibility is high that there will 

be noticeable differences between the charts and the 

databases. Because of this, pilots must be familiar with the 

capabilities of the database and have updated aeronautical 

charts while flying to ensure the proper course is being 

flown.

Naming Conventions

Obvious differences exist between the names of procedures 

shown on charts and those that appear on the displays of 

many RNAV systems. Most of these differences can be 

accounted for simply by the way the avionics manufacturers 

elect to display the information to the pilot. It is the avionics 

manufacturer that creates the interface between the pilot 

and the database. For example, the VOR 12R approach in 

San Jose, California, might be displayed several different 

ways depending on how the manufacturer designs the 

pilot interface. Some systems display procedure names 

exactly as they are charted, but many do not.
6-16

Figure 6-31. Manufacturer’s naming conventions.

The naming of multiple approaches of the same type to the 

same runway is also changing. Multiple approaches with 

the same guidance will be annotated with an alphabetical 

suffix beginning at the end of the alphabet and working 

backwards for subsequent procedures (e.g., ILS Z RWY 

28, ILS Y RWY 28, etc.). The existing annotations, such as 

ILS 2 RWY 28 or Silver ILS RWY 28, will be phased out and 

replaced with the new designation.

NAVAIDs are also subject to naming discrepancies as well. 

This problem is complicated by the fact that multiple 

NAVAIDs can be designated with the same identifier. VOR 

XYZ may occur several times in a provider’s database, so 

the avionics manufacturer must design a way to identify 

these fixes by a more specific means than the three-letter 

identifier. Selection of geographic region is used in most 

instances to narrow the pilot’s selection of NAVAIDs with 

like identifiers.

Non-directional beacons (NDBs) and locator outer markers 

(LOMs) can be displayed differently than they are charted. 

When the first airborne navigation databases were being 

implemented, NDBs were included in the database as 

waypoints instead of NAVAIDs. This necessitated the use 

of five character identifiers for NDBs. Eventually, the NDBs 

were coded into the database as NAVAIDs, but many of 

the RNAV systems in use today continue to use the fivecharacter identifier. These systems display the characters 

“NB” after the charted NDB identifier. Therefore, NDB ABC 

would be displayed as “ABCNB.”

Other systems refer to NDB NAVAIDs using either the NDB’s 

charted name if it is five or fewer letters, or the one to three 

character identifier. PENDY NDB located in North Carolina, 

for instance, is displayed on some systems as “PENDY,” while 

other systems might only display the NDBs identifier “ACZ.” 

[Figure 6-31]

Using the VOR/DME Runway 34 approach at Eugene 

Mahlon Sweet Airport (KEUG) in Eugene, Oregon, as 

another example, which is named V34, may be displayed 

differently by another avionics platform. For example, a 

GPS produced by one manufacturer might display the 

approach as VOR 34, whereas another might refer to the 

approach as VOR/DME 34, and an FMS produced by another 

manufacturer may refer to it as VOR34. These differences 

can cause visual inconsistencies between chart and GPS 

displays, as well as confusion with approach clearances 

and other ATC instructions for pilots unfamiliar with specific 

manufacturer’s naming conventions.

For detailed operational guidance, refer to Advisory Circular 

(AC) 90-100, U.S. Terminal and En Route Area Navigation 

(RNAV) Operations; AC 90-101, Approval Guidance for RNP 

Procedures with Special Aircraft and Aircrew Authorization 

Required (SAAAR); AC 90-105, Approval Guidance for RNP 

Operations and Barometric Vertical Navigation in the 

U.S. National Airspace System; and AC 90-107, Guidance 

for Localizer Performance with Vertical Guidance and 

Localizer Performance without Vertical Guidance Approach 

Operations in the U.S. National Airspace System.

Issues Related To Magnetic Variation

Magnetic variations for locations coded into airborne 

navigation databases can be acquired in several ways. In 

many cases they are supplied by government agencies in 

the epoch year variation format. Theoretically, this value 

is determined by government sources and published for 

public use every five years. Providers of airborne navigation 

databases do not use annual drift values; instead the 

database uses the epoch year variation until it is updated by 

the appropriate source provider. In the United States, this 

is the National Oceanic and Atmospheric Administration 

(NOAA). In some cases the variation for a given location is 
6-17

a value that has been calculated by the avionics system. 

These dynamic magnetic variation values can be different 

than those used for locations during aeronautical charting 

and must not be used for conventional NAVAIDs or airports.

Discrepancies can occur for many reasons. Even when the 

variation values from the database are used, the resulting 

calculated course might be different from the course 

depicted on the charts. Using the magnetic variation for the 

region instead of the actual station declination can result 

in differences between charted and calculated courses and 

incorrect ground track. Station declination is only updated 

when a NAVAID is site checked by the governing authority 

that controls it, so it is often different than the current 

magnetic variation for that location. Using an onboard 

means of determining variation usually entails coding 

some sort of earth model into the avionics memory. Since 

magnetic variation for a given location changes predictably 

over time, this model may only be correct for one time in 

the lifecycle of the avionics. This means that if the intended 

lifecycle of a GPS unit were 20 years, the point at which the 

variation model might be correct would be when the GPS 

unit was 10 years old. The discrepancy would be greatest 

when the unit was new, and again near the end of its life 

span.

Another issue that can cause slight differences between 

charted course values and those in the database 

occurs when a terminal procedure is coded using 

magnetic variation of record. When approaches or other 

procedures are designed, the designers use specific rules 

to apply variation to a given procedure. Some controlling 

government agencies may elect to use the epoch year 

variation of an airport to define entire procedures at that 

airport. This may result in course discrepancies between 

the charted value and the value calculated using the actual 

variations from the database.

Issues Related To Revision Cycle

Pilots should be aware that the length of the airborne 

navigation database revision cycle could cause 

discrepancies between aeronautical charts and information 

derived from the database. One important difference 

between aeronautical charts and databases is the length 

of cutoff time. Cutoff refers to the length of time between 

the last day that changes can be made in the revision, and 

the date the information becomes effective. Aeronautical 

charts typically have a cutoff date of 10 days prior to the 

effective date of the charts.
6-18
7-1

Introduction

This chapter presents information on IFR helicopter 

operations in the National Airspace System. Advances in 

avionics technology installed in helicopters such as Global 

Positioning System (GPS) and Wide Area Augmentation 

System (WAAS) are bringing approach procedures to 

heliports around the country.

The ability to operate helicopters under IFR increases 

their utility and safety. Helicopter IFR operators have 

an excellent safety record due to the investment in 

IFR-equipped helicopters, development of instrument 

approach procedures (IAPs), and IFR-trained flight crews. 

The safety record of IFR operations in the Gulf of Mexico is 

equivalent to the safety record of the best-rated airlines. 

Manufacturers are working to increase IFR all-weather 

capabilities of helicopters by providing slower minimum 

instrument airspeeds (VMINI), faster cruising speeds, and 

better autopilots and flight management systems (FMS). 

As a result, in October 2005, the first civil helicopter in 

the United States was certified for flight into known icing 

conditions. [Figure 7-1]

Helicopter Instrument 

Procedures

Chapter 7
7-2

Figure 7-1. Icing tests. To safely provide an all-weather capability 

and flight into known icing conditions that would otherwise delay 

or cancel winter flight operations, the digital control of the S-92 

Rotor Ice Protection System (RIPS) determines the temperature and 

moisture content of the air and removes any ice buildup by heating the 

main and tail rotor blades. The system is shown here during testing.

Helicopter Instrument Flight Rule (IFR) 

Certification 

It is very important that pilots be familiar with the IFR 

requirements for their particular helicopter. Within the 

same make, model, and series of helicopter, variations in 

the installed avionics may change the required equipment 

or the level of augmentation for a particular operation. The 

Automatic Flight Control System/Autopilot/Flight Director 

(AFCS/AP/FD) equipment installed in IFR helicopters can 

be very complex. For some helicopters, the AFCS/AP/

FD complexity requires formal training in order for the 

pilot(s) to obtain and maintain a high level of knowledge 

of system operation, limitations, failure indications, and 

reversionary modes. For a helicopter to be certified 

to conduct operations in instrument meteorological 

conditions (IMC), it must meet the design and installation 

requirements of Title 14 Code of Federal Regulations (14 

CFR) Part 27, Appendix B (Normal Category) and Part 29, 

Appendix B (Transport Category), which is in addition to 

the visual flight rule (VFR) requirements.

These requirements are broken down into the 

following categories: flight and navigation equipment, 

miscellaneous requirements, stability, helicopter flight 

manual limitations, operations specifications, and 

minimum equipment list (MEL).

Flight and Navigation Equipment 

The basic installed flight and navigation equipment for 

helicopter IFR operations is listed under 14 CFR Part 29, 

section 29.1303, with amendments and additions in 

Appendix B of 14 CFR Parts 27 and 29 under which they are 

certified. The list includes: 

• 	 Clock

• 	 Airspeed indicator

• 	 Sensitive altimeter (A“sensitive”altimeter relatesto

the instrument’s displayed change in altitude over its 

range. For “Copter” Category (CAT) II operations, 

the scale must be in 20-foot intervals.) adjustable for 

barometric pressure 

• 	 Magnetic direction indicator

• 	 Free-air temperature indicator

• 	 Rate-of-climb (vertical speed) indicator

• 	 Magnetic gyroscopic direction indicator

• 	 Stand-by bank and pitch (attitude) indicator

• 	 Non-tumbling gyroscopic bank and pitch (attitude)

indicator 

• 	 Speed warning device (ifrequired by 14 CFR Part 29)

Miscellaneous Requirements 

•	 Overvoltage disconnect

•	 Instrument power source indicator

•	 Adequate ice protection of IFR systems

•	 Alternate static source (single-pilot configuration)

•	 Thunderstormlights(transport categoryhelicopters)

Stabilization and Automatic Flight Control 

System (AFCS) 

Helicopter manufacturers normally use a combination 

of a stabilization and/or AFCS in order to meet the IFR 

stability requirements of 14 CFR Parts 27 and 29. These 

systems include: 

• Aerodynamic surfaces, which impart some stability 

or control capability that generally is not found in 

the basic VFR configuration.

•	 Trim systems provide a cyclic centering effect.These

systems typically involve a magnetic brake/spring 

device and may be controlled by a four-way switch 

on the cyclic. This system requires “hands on” flying 

of the helicopter.

•	 Stability Augmentation Systems (SAS) provide

short-term rate damping control inputs to increase 

helicopter stability. Like trim systems, SAS requires 

“hands-on” flying.
7-3

• Attitude Retention Systems (ATT ) return the 

helicopter to a selected attitude after a disturbance. 

Changes in attitude can be accomplished usually 

through a four- way “beep” switch or by actuating a 

“force trim” switch on the cyclic, which sets the desired 

attitude manually. Attitude retention may be a SAS 

function or may be the basic “hands off” autopilot 

function.

•	 Autopilot Systems (APs) provide for “hands off”

flight along specified lateral and vertical paths. The 

functional modes may include heading, altitude, 

vertical speed, navigation tracking, and approach. 

APs typically have a control panel for mode selection 

and indication of mode status. APs may or may not be 

installed with an associated FD. APs typically control 

the helicopter about the roll and pitch axes (cyclic 

control) but may also include yaw axis (pedal control) 

and collective control servos.

•	 Flight Directors (FDs) provide visual guidance to

the pilot to fly selected lateral and vertical modes of 

operation. The visual guidance is typically provided 

by a “single cue,” commonly known as a “vee bar,” 

which provides the indicated attitude to fly and 

is superimposed on the attitude indicator. Other 

FDs may use a “two cue” presentation known as a 

“cross pointer system.” These two presentations 

only provide attitude information. A third system, 

known as a “three cue” system, provides information 

to position the collective as well as attitude (roll 

and pitch) cues. The collective control cue system 

identifies and cues the pilot what collective control 

inputs to use when path errors are produced or when 

airspeed errors exceed preset values. The three-cue 

system pitch command provides the required cues 

to control airspeed when flying an approach with 

vertical guidance at speeds slower than the bestrate-of-climb (BROC) speed. The pilot manipulates 

the helicopter’s controls to satisfy these commands, 

yielding the desired flightpath or may couple the 

autopilot to the FD to fly along the desired flightpath. 

Typically, FD mode control and indication are shared 

with the autopilot. Pilots must be aware of the mode 

of operation of the augmentation systems and the 

control logic and functions in use. For example, on an 

instrument landing system (ILS) approach and using 

the three-cue mode (lateral, vertical, and collective 

cues), the FD collective cue responds to glideslope 

deviation, while the horizontal bar cue of the “crosspointer” responds to airspeed deviations. However, 

the same system when operated in the two-cue 

mode on an ILS, the FD horizontal bar cue responds 

to glideslope deviations. The need to be aware of the 

FD mode of operation is particularly significant when 

operating using two pilots. 

Pilots should have an established set of procedures and 

responsibilities for the control of FD/AP modes for the 

various phases of flight. Not only does a full understanding 

of the system modes provide for a higher degree of 

accuracy in control of the helicopter, it is the basis for crew 

identification of a faulty system.

Helicopter Flight Manual Limitations 

Helicopters are certificated for IFR operations with either 

one or two pilots. Certain equipment is required to be 

installed and functional for two-pilot operations and 

additional equipment is required for single-pilot operation.

In addition, the Helicopter Flight Manual (HFM) defines 

systems and functions that are required to be in operation 

or engaged for IFR flight in either the single or two-pilot 

configurations. Often, in a two-pilot operation, this level of 

augmentation is less than the full capability of the installed 

systems. Likewise, a single-pilot operation may require a 

higher level of augmentation.

The HFM also identifies other specific limitations associated 

with IFR flight. Typically, these limitations include, but are 

not limited to: 

• 	 Minimum equipmentrequired forIFR flight(in some

cases, for both single-pilot and two-pilot operations)

•	 VMINI (minimum speed—IFR) [Figure 7-2]

•	 VNEI (never exceed speed—IFR)

• 	 Maximum approach angle

• 	 Weight and center of gravity (CG) limits

• 	 Helicopter configuration limitations (such as door

positions and external loads)

• 	 Helicoptersystem limitations(generators, inverters,

etc.) 

• 	 Systemtestingrequirements(manyavionicsandAFCS,

AP, and FD systems incorporate a self-test feature) 

• 	 Pilotactionrequirements(forexample,thepilotmust

have hands and feet on the controls during certain 

operations, such as an instrument approach below 

certain altitudes) 

Final approach angles/descent gradient for public 

approach procedures can be as high as 7.5 degrees/795 

feet per nautical mile (NM). At 70 knots indicated airspeed 

(KIAS) (no wind), this equates to a descent rate of 925 feet 

per minute (fpm). With a 10-knot tailwind, the descent 

rate increases to 1,056 fpm. “Copter” Point-in-space (PinS) 

approach procedures are restricted to helicopters with a 

maximum VMINI of 70 KIAS and an IFR approach angle that 

enables them to meet the final approach angle/descent 

gradient. Pilots of helicopters with a VMINI of 70 KIAS may 
7-4

Figure 7-2. VMINI limitations, maximum IFR approach angles and G/A mode speeds for selected IFR certified helicopters. 

Augusta

A-109

A-109C

Bell

BH 212

BH 214ST

BH 222

BH 222B

BH 412

BH 430

Eurocopter

AS-355

AS-365

BK-117

EC-135

EC-155

Sikorsky

S-76A

S-76A

S-76B

S-76C

SK-76C++

9.0

5.0

4.0

4.5

4.5

6.0

4.6

4.0

3.5

7.5

7.5

6.5

NOTE: The VMINI, MAX IFR Approach Angle and G/A Mode Speed for a specific helicopter may vary with avionics/autopilot installation. 

Pilots are therefore cautioned to refer only to the Rotorcraft Flight Manual limitations for their specific helicopter. The maximum rate of 

descent for many autopilots is 1,000 FPM.

LEGEND

 In some helicopters with the autopilot engaged, the VMINI may increase to a speed greater than 70 KIAS, or in the “go around” 

 mode requires a speed faster than 70 KIAS. 

SAMPLE NOT FOR ACTUAL USE

Manufacturer VMINI Limitations MAX IFR Approach Angle G/A Mode Speed

75 KIAS

75 KIAS

75 KIAS

60 (80 coupled)

40

40

70

50

50

60

50 (65 coupled)

55

75

45 (70 coupled)

60

70

60 (AFCS Phase II)

50 (AFCS Phase III)

60

60

50 (60 coupled)

have inadequate control margins to fly an approach that 

is designed with the maximum allowable angle/descent 

gradient or minimum allowable deceleration distance 

from the missed approach point (MAP) to the heliport. 

The “Copter” PinS final approach segment is limited to 70 

KIAS since turn containment and the deceleration distance 

from the MAP to the heliport may not be adequate at faster 

speeds. For some helicopters, engaging the autopilot may 

increase the VMINI to a speed greater than 70 KIAS, or in 

the “go around” (G/A) mode, require a speed faster than 70 

KIAS. [Figure 7-2] It may be possible for these helicopters 

to be flown manually on the approach or on the missed 

approach in a mode other than the G/A mode.

Since slower IFR approach speeds enable the helicopter 

to fly steeper approaches and reduces the distance from 

the heliport that is required to decelerate the helicopter, 

you may want to operate your helicopter at speeds slower 

than its established VMINI. The provision to apply for a 

determination of equivalent safety for instrument flight 

below VMINI and the minimum helicopter requirements 

are specified in Advisory Circulars (AC) 27-1, “Certification 

of Normal Category Rotorcraft” and AC 29-2, “Certification 

of Transport Category Rotorcraft.” Application guidance is 

available from the Rotorcraft Directorate Standards Staff, 

ASW-110, 2601 Meacham Blvd., Fort Worth, Texas, 76137-

4298, (817) 222-5111.

Performance data may not be available in the HFM for 

speeds other than the best rate of climb speed. To meet 

missed approach climb gradients, pilots may use observed 

performance for similar weight, altitude, temperature, and 

speed conditions to determine equivalent performance. 

When missed approaches utilizing a climbing turn are 

flown with an autopilot, set the heading bug on the 

missed approach heading, and then at the MAP, engage 

the indicated airspeed mode, followed immediately by 

applying climb power and selecting the heading mode. 

This is important since the autopilot roll rate and maximum 

bank angle in the Heading Select mode are significantly 
7-5

Figure 7-3. Autopilot bank angle and roll rate limits for the S-76 

used by the William J. Hughes Technical Center for Flight Tests.

Figure 7-4. Flight tests at the William J. Hughes Technical Center 

point out the importance of airspeed control and using the correct 

technique to make a turning missed approach.

Heading hold

VOR/RNAV

(Capture)

VOR/RNAV

(On Course)

Heading Select

VOR/RNAV

(Course Change

Over Station/Fix)

<6

+/–22

+/–13

+/–20

+/–17

None specified

5

1

5 VOR/RNAV Approach

5

1

Bank Angle Limit

(Degrees)

Roll Rate Limit

(Degrees/Sec)

Autopilot 

Mode

SAMPLE NOT FOR ACTUAL USE

MAP 1000 ft.2000 ft.3000 ft.4000 ft.5000 ft.6000 ft.7000 ft.8000 ft.

Distance from MAP

× × × × ×

× × × × × × ×

Bin Mean

Bin Maximum

Approach Tracks

Legend

×

more robust than in the NAV mode. Figure 7-3 represents 

the bank angle and roll limits of the S76 used by the Federal 

Aviation Administration (FAA) for flight testing. It has a roll 

rate in the Heading Select mode of 5 degrees per second 

with only 1 degree per second in the NAV mode. The bank 

angle in the Heading Select mode is 20 degrees, with only 

17 degrees in the NAV Change Over mode. Furthermore, if 

the Airspeed Hold mode is not selected on some autopilots 

when commencing the missed approach, the helicopter 

accelerates in level flight until the best rate of climb is 

attained, and only then will a climb begin. 

WAAS localizer performance (LP) lateral-only PinS testing 

conducted in 2005 by the FAA at the William J. Hughes 

Technical Center in New Jersey for helicopter PinS also 

captured the flight tracks for turning missed approaches. 

[Figure 7-4] The large flight tracks that resulted during 

the turning missed approach were attributed in part to 

operating the autopilot in the NAV mode and exceeding 

the 70 KIAS limit.

Operations Specifications

A flight operated under 14 CFR Part 135 has minimums and 

procedures more restrictive than a flight operated under

14 CFR Part 91. These Part 135 requirements are detailed 

in their operations specifications (OpSpecs). Helicopter 

Emergency Medical Service (HEMS) operators have even 

more restrictive OpSpecs. Shown in Figure 7-5 is an excerpt 

from an OpSpecs detailing the minimums for precision 

approaches. The inlay in Figure 7-5 shows the minimums for 

the ILS Runway 3R approach at Detroit Metro Airport. With 

all lighting operative, the minimums for helicopter Part

91 operations are a 200-foot ceiling, and 1,200-feet runway 

visual range (RVR) - one-half airplane Category A visibility 

but no less than 1⁄4 SM/1,200 RVR. However, as shown in 

the OpSpecs, the minimum visibility this Part 135 operator 

must adhere to is 1,600 RVR. Pilots operating under 14 CFR 

Part 91 are encouraged to develop their own personal 

OpSpecs based on their own equipment, training, and 

experience.

Minimum Equipment List (MEL)

A helicopter operating under 14 CFR Part 135 with 

certain installed equipment inoperative is prohibited 

from taking off unless the operation is authorized in the 

approved MEL. The MEL provides for some equipment to 

be inoperative if certain conditions are met. [Figure 7-6] 

In many cases, a helicopter configured for single-pilot 

IFR may depart IFR with certain equipment inoperative 

provided a crew of two pilots is used. Under 14 CFR Part 

91, a pilot may defer certain items without an MEL if 

those items are not required by the type certificate, CFRs, 

or airworthiness directives (ADs), and the flight can be 

performed safely without them. If the item is disabled, 

removed, or marked inoperative, a logbook entry is made.

Pilot Proficiency 

Helicopters of the same make and model may have 

variations in installed avionics that change the required 

equipment or the level of augmentation for a particular 

operation. The complexity of modern AFCS, AP, and FD 

systems requires a high degree of understanding to safely 

and efficiently control the helicopter in IFR operations. 

Formal training in the use of these systems is highly 
7-6

Figure 7-5. Operations Specifications. 

SAMPLE NOT FOR ACTUAL USE

U.S. Department

of Transportation 

Federal Aviation Operations Specifications 

 Administration

Print Date: 4/16/2008 H117-1

H117. Straight-in Category I Precision Instrument Approach HQ Control: 11/22/00

Procedures - All Airports HQ Revision: 000

a. Except as provided in this paragraph, the certificate holder shall not use any Category I IFR landing 

minimum lower than that prescribed by any applicable published instrument approach procedure. The 

IFR landing minimums prescribed in this paragraph are the lowest authorized (other than Airborne 

Radar approaches) for use at any airport. Provided that the fastest approach speed used in the final 

approach segment is less than 91 knots, the certificate holder is authorized to conduct straight-in 

precision instrument approach procedures using the following:

(1) The published Category A minimum descent altitude (MDA) or decision height (DH), as 

appropriate.

(2) One-half of the published Category A visibility/RVR minimum or the visibility/RVR minimums 

prescribed by this paragraph, whichever is higher.

b. Straight-In Category I Precision Approach Procedures. The certificate holder shall not use an IFR 

landing minimum for straight-in precision approach procedures lower than that specified in the 

following table. Touchdown zone RVR reports, when available for a particular runway, are controlling 

for all approaches to and landings on that runway. (See NOTE 2.)

Precision Approaches Full ILS (See NOTE 1), MLS, or PAR

Approach Light 

Configuration

HAT Helicopters Operated at

Speeds of 90 Knots or Less

Helicopters Operated at

Speeds More Than 90 Knots

Visibility In 

SM.

TDZ RVR 

In Feet

Visibility In 

SM.

TDZ RVR In 

Feet

No Lights or ODALS or 

MALS or SSALS

200 3/4 3500 3/4 4000

MALSR or SSALR or 

ALSF-1 or ALSF-2

200 1/4 1600 1/2 2400

MALSR with TDZ and 

CL or SSALR with TDZ 

and CL or ALSF-1/ALSF2 with TDZ and CL

200 1/4 1600 1/2 1800

NOTE 1: A full ILS requires an operative LOC, GS, and OM or FAF. A precision or surveillance radar 

fix, an NDB, VOR, DME fix, or a published minimum GSIA fix may be used in lieu of an outer marker.

NOTE 2: The Mid RVR and Rollout RVR reports (if available) provide advisory information to pilots.

The Mid RVR report may be substituted for the TDZ RVR report if the TDZ RVR report is not available.

c. Special Limitations and Provisions for Instrument Approach Procedures at Foreign Airports. If the 

certificate holder is authorized operations at foreign airports, the following criteria apply.

(1) Foreign approach lighting systems equivalent to U.S. standards are authorized for both precision 

and nonprecision approaches. Sequenced flashing lights are not required when determining the 

equivalence of a foreign lighting system to U.S. standards.

(2) For straight-in landing minimums at foreign airports where an MDA or DH is not specified, the 

lowest authorized MDA or DH shall be obtained as follows:

SAMPLE NOT FOR ACTUAL USE

SAMPLE NOT FOR ACTUAL USE
7-7

Figure 7-6. Example of a Minimum Equipment List (MEL). 

U.S. DEPARTMENT OF TRANSPORTATION

MASTER MINIMUM EQUIPMENT LIST

FEDERAL AVIATION ADMINISTRATION

AIRCRAFT:

BH-206/407 SERIES

REVISION NO: 3

DATE: 12/22/2008

PAGE:

28-1

1. 2. NUMBER INSTALLED

3. NUMBER REQUIRED FOR DISPATCH

SYSTEM &

SEQUENCE

NUMBERS

ITEM

4. REMARKS OR EXCEPTIONS

28 FUEL 

1. Fuel Quantity Gauge DELETED. |

2.

***

Auxiliary Fuel Tank D - 0 May be inoperative provided:

a) Flight is not predicated upon

the use of the system,

and

b) Auxiliary tank fuel is

considered in weight and

balance computations.

3. Fuel Low Warning Caution

Light System(206A and

206B only)

DELETED. |

|

|

(206L series and407

only)

DELETED. |

|

4.

***

Solenoid Drain Valve

System

D - 0 (O) May be inoperative provided the

manual drain valve is verified

closed prior to flight.

5. Fuel Boost Pump(Twin

engine models only)

B 4 3 One aft boost pump may be

inoperative.

6. Fuel Flow Indicator

(Twin engine models

only)

B 2 0

SAMPLE NOT FOR ACTUAL USE
7-8

Figure 7-7. Helicopter VFR minimums. 

Airspace

Class A

Class B

Class C

Class D

Class E

Less than 

10,000 feet MSL

At or above 

10,000 feet MSL

Class G

1,200 feet or less 

above the surface 

(regardless of MSL altitude)

Day, except as provided

in §91.155(b)

Night, except as provided

in §91.155(b)

More than 1,200 feet above

the surface but less than

10,000 feet MSL

Day

Night

More than 1,200 feet 

above the surface and at 

or above 10,000 feet MSL

B, C, D, E, Surface Area 

Airspace SVFR Minimums

Day

Night

Flight 

visibility

Not 

applicable

3 SM

3 SM

3 SM

3 SM

5 SM

None

None

1 SM

3 SM

5 SM

None

None

Distance from clouds

Not applicable

Clear of clouds

500 feet below

1,000 feet above

2,000 feet horizontal

500 feet below

1,000 feet above

2,000 feet horizontal

500 feet below

1,000 feet above

2,000 feet horizontal

1,000 feet below

1,000 feet above

1 statue mile horizontal

Clear of clouds

Clear of clouds

500 feet below

1,000 feet above

2,000 feet horizontal

500 feet below

1,000 feet above

2,000 feet horizontal

1,000 feet below

1,000 feet above

1 statute mile horizontal

Clear of clouds

Clear of clouds

Helicopter VFR Minimums recommended for all pilots.

During flight operations, you must be aware of the mode 

of operation of the augmentation system and the control 

logic and functions employed. [Figure 7-2] 

Helicopter VFR Minimums

Helicopters have the same VFR minimums as airplanes 

with two exceptions. In Class G airspace or under a special 

visual flight rule (SVFR) clearance, helicopters have no 

minimum visibility requirement but must remain clear of 

clouds and operate at a speed that is slow enough to give 

the pilot an adequate opportunity to see other aircraft or 

an obstruction in time to avoid a collision. Helicopters are 

also authorized (14 CFR Part 91, appendix D, section 3) to 

obtain SVFR clearances at airports with the designation 

NO SVFR in the Airport Facility Directory (A/FD) or on the 

sectional chart. Figure 7-7 shows the visibility and cloud 

clearance requirements for VFR and SVFR. However, lower 

minimums associated with Class G airspace and SVFR do 

not take the place of the VFR minimum requirements of 

either Part 135 regulations or respective OpSpecs. 

Knowledge of all VFR minimums is required in order to 

determine if a PinS approach can be conducted or if a SVFR 

clearance is required to continue past the (MAP). These 

approaches and procedures are discussed in detail later. 

Helicopter IFR Takeoff Minimums

A pilot operating under 14 CFR Part 91 has no takeoff 

minimums to comply with other than the requirement to 

attain VMINI before entering IMC. For most helicopters, 

this requires a distance of approximately 1⁄2 mile and 

an altitude of 100 feet. If departing with a steeper climb 

gradient, some helicopters may require additional altitude 

to accelerate to VMINI. To maximize safety, always consider 

using the Part 135 operator standard takeoff visibility 

minimum of 1⁄2 statute mile (SM) or the charted departure 

minima, whichever is higher. A charted departure that 

provides protection from obstacles has either a higher 

visibility requirement, climb gradient, and/or departure 

path. Part 135 operators are required to adhere to the 

takeoff minimums prescribed in the instrument approach 

procedures (IAPs) for the airport

Helicopter IFR Alternates 

The pilot must file for an alternate if weather reports and 

forecasts at the proposed destination do not meet certain 

minimums. These minimums differ for Part 91 and Part 

135 operators. 

Part 91 Operators

Part 91 operators are not required to file an alternate if, at 

the estimated time of arrival (ETA) and for 1 hour after, the 

ceiling is at least 1,000 feet above the airport elevation or 

400 feet above the lowest applicable approach minima, 

whichever is higher, and the visibility is at least 2 SM. If an 

alternate is required, an airport can be used if the ceiling is 

at least 200 feet above the minimum for the approach to 

be flown and visibility is at least 1 SM, but never less than 

the minimum required for the approach to be flown. If no 

instrument approach procedure has been published for the 

alternate airport, the ceiling and visibility minima are those 

allowing descent from the MEA, approach, and landing 

under basic VFR.
7-9

Figure 7-8. Part 97 excerpt. 

Figure 7-9. Helicopter use of standard instrument approach procedures. 

b) (1) “Copter procedures” means helicopter procedures 

 with applicable minimums as prescribed in §97.35 

 of this part. Helicopters may also use other 

 procedures prescribed in Subpart C of this part and 

 may use the Category A minimum descent altitude 

 (MDA) or decision height (DH). The required visibility 

 minimum may be reduced to 1⁄2 the published 

 visibility minimum, but in no case may it be reduced 

 to less than one-quarter mile or 1,200 feet RVR.

97.3 Symbols and Terms Used in Procedures

Procedure

Standard

Copter Procedure

GPS Copter Procedure

Helicopter Visibility Minima

The greater of: one half the

Category A visibility minima,

1⁄4 statute mile visibility or

1,200 RVR unless annotated

(Visibility Reduction by 

Helicopters NA.)

As published

As published

Helicopter MDA/DA

As published for

Category A

As published

As published

Maximum Speed Limitations

The helicopter may initiate the final approach 

segment at speeds up to the upper limit of the 

highest Approach Category authorized by the 

procedure, but must be slowed to no more 

than 90 KIAS at the MAP in order to apply the 

visibility reduction.

90 KIAS when on a published route/track.

90 KIAS when on a published route, track, or 

holding, 70 KIAS when on the final approach 

or missed approach segment. Military procedures 

are limited to 90 KIAS for all segments.

Helicopter Use of Standard Instrument Approach Procedures

Part 135 Operators

Part 135 operators are not required to file an alternate if, for 

at least 1 hour before and 1 hour after the ETA, the ceiling 

is at least 1,500 feet above the lowest circling approach 

minimum descent altitude (MDA). If a circling instrument 

approach is not authorized for the airport, the ceiling must 

be at least 1,500 feet above the lowest published minimum 

or 2,000 feet above the airport elevation, whichever is 

higher. For the IAP to be used at the destination airport, the 

forecasted visibility for that airport must be at least 3 SM or 

2 SM more than the lowest applicable visibility minimums, 

whichever is greater.

Alternate landing minimums for flights conducted under 14

CFR Part 135 are described in the OpSpecs for that 

operation. All helicopters operated under IFR must carry 

enough fuel to fly to the intended destination, fly from that 

airport to the filed alternate, if required, and continue for 

30 minutes at normal cruising speed.

Helicopter Instrument Approaches

Many new helicopter IAPs have been developed to take 

advantage of advances in both avionics and helicopter 

technology.

Standard Instrument Approach Procedures to 

an Airport

Helicopters flying standard instrument approach 

procedures (SIAP) must adhere to the MDA or decision 

altitude for Category A airplanes and may apply the 14 

CFR Part 97.3 (d-1) rule to reduce the airplane Category A 

visibility by half but in no case less than 1⁄4 SM or 1,200 RVR. 

[Figure 7-8] The approach can be initiated at any speed up 

to the highest approach category authorized; however, the 

speed on the final approach segment must be reduced to 

the Category A speed of less than 90 KIAS before the MAP in 

order to apply the visibility reduction. A constant airspeed 

is recommended on the final approach segment to comply 

with the stabilized approach concept since a decelerating 

approach may make early detection of wind shear on the 

approach path more difficult. [Figure 7-9]

When visibility minimums must be increased for inoperative 

components or visual aids, use the Inoperative Components 

and Visual Aids Table (provided in the front cover of the U.S. 

Terminal Procedures) to derive the Category A minima before 

applying any visibility reduction. The published visibility 

may be increased above the standard visibility minima due 

to penetrations of the 20:1 and 34:1 final approach obstacle 

identification surfaces (OIS). The minimum visibility required 

for 34:1 penetrations is 3⁄4 SM and for 20:1 penetrations 1 

SM, which is discussed in Chapter 5 of this handbook. When 

there are penetrations of the final approach OIS, a visibility 

credit for approach lighting systems is not allowed for 

either airplane or helicopter procedures that would result 

in values less than the appropriate 3⁄4 SM or 1 SM visibility 

requirement. The 14 CFR Part 97.3 visibility reduction rule 

does not apply, and you must take precautions to avoid 

any obstacles in the visual segment. Procedures with 

penetrations of the final approach OIS are annotated at the 

next amendment with “Visibility Reduction by Helicopters 

NA.”
7-10

Until all the affected SIAPs have been annotated, an 

understanding of how the standard visibilities are 

established is the best aid in determining if penetrations 

of the final approach OIS exists. Some of the variables in 

determining visibilities are: density altitude (DA)/MDA 

height above touchdown (HAT), height above airport 

(HAA), distance of the facility to the MAP (or the runway 

threshold for non- precision approaches), and approach 

lighting configurations.

The standard visibility requirement, without any credit 

for lights, is 1 SM for non-precision approaches and 3⁄4 

SM for precision approaches. This is based on a Category 

A airplane 250–320 feet HAT/HAA; for non-precision 

approaches a distance of 10,000 feet or less from the 

facility to the MAP (or runway threshold). For precision 

approaches, credit for any approach light configuration; for 

non-precision approaches (with a 250 HAT) configured with 

a Medium Intensity Approach Lighting System (MALSR), 

Simplified Short Approach Lighting System (SSALR), or 

Approach Lighting System With Sequenced Flashing Lights 

(ALSF)-1 normally results in a published visibility of 1⁄2 SM.

Consequently, if an ILS is configured with approach lights 

or a non-precision approach is configured with MALSR, 

SSALR, or ALSF-1 lighting configurations and the procedure 

has a published visibility of 3⁄4 SM or greater, a penetration 

of the final approach OIS may exist. Also, pilots are unable 

to determine whether there are penetrations of the final 

approach OIS if a non-precision procedure does not have 

approach lights or is configured with ODALS, MALS, 

or SSALS/ SALS lighting since the minimum published 

visibility is 3⁄4 SM or greater.

As a rule of thumb, approaches with published visibilities of

3⁄4 SM or more should be regarded as having final approach 

OIS penetrations and care must be taken to avoid any 

obstacles in the visual segment.

Approaches with published visibilities of 1⁄2 SM or less are 

free of OIS penetrations and the visibility reduction in Part

97.3 is authorized.

Copter Only Approaches to An Airport or 

Heliport 

Pilots flying Copter SIAPs, other than GPS, may use the 

published minima with no reductions in visibility allowed. 

The maximum airspeed is 90 KIAS on any segment of the 

approach or missed approach. Figure 7-10 illustrates the 

COPTER ILS or LOC RWY 13 approach at New York/La Guardia 

(LGA) airport.

Copter ILS approaches to Category (CAT) I facilities with 

DAs no lower than a 200-foot HAT provide an advantage 

over a conventional ILS of shorter final segments and lower 

minimums (based on the 20:1 missed approach surface). 

There are also Copter approaches with minimums as low as

100-foot HAT and 1⁄4 SM visibility. Approaches with a HAT

below 200 feet are annotated with the note: “Special Aircrew

& Aircraft Certification Required” since the FAA must approve 

the helicopter and its avionics, and the flight crew must have 

the required experience, training, and checking.

The ground facilities (approach lighting, signal in space, hold 

lines, maintenance, etc.) and air traffic infrastructure for CAT 

II ILS approaches are required to support these procedures. 

The helicopter must be equipped with an AP, FD, or head 

up guidance system, alternate static source (or heated static 

source), and radio altimeter. The pilot must have at least a 

private pilot helicopter certificate, an instrument helicopter 

rating, and a type rating if the helicopter requires a type 

rating. Pilot experience requires the following flight times:

250 pilot in command (PIC), 100 helicopter PIC, 50 night 

PIC, 75 hours of actual or simulated instrument flight time, 

including at least 25 hours of actual or simulated instrument 

flight time in a helicopter or a helicopter flight simulator, and 

the appropriate recent experience, training and check. For 

Copter CAT II ILS operations below 200 feet HAT, approach 

deviations are limited to 1⁄4 scale of the localizer or glide 

slope needle. Deviations beyond that require an immediate 

missed approach unless the pilot has at least one of the visual 

references in sight and otherwise meets the requirements of

14 CFR Part 91.175(c). The reward for this effort is the ability 

to fly Copter ILS approaches with minima that are sometimes 

below the airplane CAT II minima. The procedure to apply for 

this certification is available from your local Flight Standards 

District Office (FSDO).

Copter GPS Approaches to an Airport or 

Heliport

Pilots flying Copter GPS or WAAS SIAPs must limit the speed 

to 90 KIAS on the initial and intermediate segment of the 

approach and to no more than 70 KIAS on the final and 

missed approach segments. If annotated, holding may also 

be limited to 90 KIAS to contain the helicopter within the 

small airspace provided for helicopter holding patterns. 

During testing for helicopter holding, the optimum 

airspeed and leg length combination was determined to 

be 90 KIAS with a 3 NM outbound leg length. Consideration 

was given to the wind drift on the dead reckoning entry 

leg at slower speeds, the turn radius at faster airspeeds, 

and the ability of the helicopter in strong wind conditions 

to intercept the inbound course prior to the holding fix. 

The published minimums are to be used with no visibility 
7-11

Figure 7-10. The COPTER ILS or LOC RWY 13 approach at New York/La Guardia (LGA) airport.

NE-2, 23 AUG 2012 to 20 SEP 2012

NE-2, 23 AUG 2012 to 20 SEP 2012
7-12

Figure 7-11. COPTER RNAV (GPS) 291° at Indianapolis Downtown Heliport.

EC-2, 23 AUG 2012 to 20 SEP 2012

EC-2, 23 AUG 2012 to 20 SEP 2012
7-13

Figure 7-12. Obstacle clearance surface (OCS). 

The Copter 20:1 OCS provides for a lower MDA for the helicopter than for the airplane. A climb gradient 

of 400 feet/NM will allow a required obstacle clearance (ROC) of 96 feet/NM for each NM of flightpath.

MAP 400 feet/NM (standard)

200 feet/NM (standard)

20:1 OSC

40:1 OSC

96 feet/NM

48 feet/NM

20:1 versus 40:1 Obstacle clearance surface (OCS) for nonprecision missed approach procedures

reductions allowed. Figure 7-11 is an example of a Copter 

GPS PinS approach that allows the helicopter to fly VFR 

from the MAP to the heliport. 

The final and missed approach protected airspace providing 

obstacle and terrain avoidance is based on 70 KIAS, with 

a maximum 10-knot tailwind component. It is absolutely 

essential that pilots adhere to the 70 KIAS limitation 

in procedures that include an immediate climbing 

and turning missed approach. Exceeding the airspeed 

restriction increases the turning radius significantly and 

can cause the helicopter to leave the missed approach 

protected airspace. This may result in controlled flight into 

terrain (CFIT) or obstacles.

If a helicopter has a VMINI greater than 70 knots, then 

it is not capable of conducting this type of approach. 

Similarly, if the autopilot in “go-around” mode climbs at a 

VYI greater than 70 knots, then that mode cannot be used. 

It is the responsibility of the pilot to determine compliance 

with missed approach climb gradient requirements 

when operating at speeds other than VY or VYI. Missed 

approaches that specify an “IMMEDIATE CLIMBING TURN” 

have no provision for a straight ahead climbing segment 

before turning. A straight segment results in exceeding the 

protected airspace limits.

Protected obstacle clearance areas and surfaces for the 

missed approach are established on the assumption that 

the missed approach is initiated at the DA point and for 

non-precision approaches no lower than the MDA at the 

MAP (normally at the threshold of the approach end of 

the runway). The pilot must begin the missed approach at 

those points. Flying beyond either point before beginning 

the missed approach results in flying below the protected 

obstacle clearance surface (OCS) and can result in a collision 

with an obstacle.

The missed approach segment U.S. Standard for Terminal 

Instrument Procedures (TERPS) criteria for all Copter 

approaches take advantage of the helicopter’s climb 

capabilities at slow airspeeds, resulting in high climb 

gradients. [Figure 7-12] The OCS used to evaluate the 

missed approach is a 20:1 inclined plane. This surface is 

twice as steep for the helicopter as the OCS used to evaluate 

the airplane missed approach segment. The helicopter 

climb gradient is therefore required to be double that of 

the airplane’s required missed approach climb gradient.

A minimum climb gradient of at least 400 feet per NM 

is required unless a higher gradient is published on the 

approach chart (e.g., a helicopter with a ground speed of 

70 knots is required to climb at a rate of 467 fpm (467 fpm 

= 70 KIAS × 400 feet per NM/60 seconds)). The advantage 

of using the 20:1 OCS for the helicopter missed approach 

segment instead of the 40:1 OCS used for the airplane is 

that obstacles that penetrate the 40:1 missed approach 

segment may not have to be considered. The result is 

the DA/MDA may be lower for helicopters than for other 

aircraft. The minimum required climb gradient of 400 feet 

per NM for the helicopter in a missed approach provides 

96 feet of required obstacle clearance (ROC) for each NM 

of flightpath.
7-14

Helicopter Approaches to VFR Heliports

Helicopter approaches to VFR heliports are normally 

developed either as public procedures to a PinS that may 

serve more than one heliport or as a special procedure 

to a specific VFR heliport that requires pilot training due 

to its unique characteristics. These approaches can be 

developed using very high frequency omni-directional 

range (VOR) or automatic direction finder (ADF), but area 

navigation (RNAV) using GPS is the most common system 

used today. In the future, RNAV using the WAAS offers the 

most advantages because it can provide lower approach 

minimums, narrower route widths to support a network of 

approaches, and may allow the heliport to be used as an 

alternate. A majority of the special procedures to a specific 

VFR heliport are developed in support of HEMS operators 

and have a “Proceed Visually” segment between the MAP 

and the heliport. Public procedures are developed as a PinS 

approach with a “Proceed VFR” segment between the MAP 

and the landing area. These PinS “Proceed VFR” procedures 

specify a course and distance from the MAP to the available 

heliports in the area.

Approach to a PinS 

The note associated with these procedures is: “PROCEED 

VFR FROM (NAMED MAP) OR CONDUCT THE SPECIFIED 

MISSED APPROACH.” They may be developed as a special 

or public procedure where the MAP is located more than 2 

SM from the landing site, the turn from the final approach 

to the visual segment is greater than 30 degrees, or the VFR 

segment from the MAP to the landing site has obstructions 

that require pilot actions to avoid them. Figure 7-13 is an 

example of a public PinS approach that allows the pilot to 

fly to one of four heliports after reaching the MAP.

For Part 135 operations, pilots may not begin the instrument 

approach unless the latest weather report indicates that the 

weather conditions are at or above the authorized IFR or VFR 

minimums as required by the class of airspace, operating rule 

and/or OpSpecs, whichever is higher. Visual contact with the 

landing site is not required; however, prior to the MAP, for 

either Part 91 or 135 operators, the pilot must determine if 

the flight visibility meets the basic VFR minimums required 

by the class of airspace, operating rule and/or OpSpecs 

(whichever is higher). The visibility is limited to no lower 

than that published in the procedure until canceling IFR. If 

VFR minimums do not exist, then the published MAP must 

be executed. The pilot must contact air traffic control (ATC) 

upon reaching the MAP, or as soon as practical after that, and 

advise whether executing the missed approach or canceling 

IFR and proceeding VFR. Figure 7-14 provides examples of 

the procedures used during a PinS approach for Part 91 and 

Part 135 operations.

To proceed VFR in uncontrolled airspace, Part 135 operators 

are required to have at least 1⁄2 SM visibility and a 300-foot 

ceiling. Part 135 HEMS operators must have at least 1 SM day 

or 2 SM night visibility and a 500-foot ceiling provided the 

heliport is located within 3 NM of the MAP. These minimums 

apply regardless of whether the approach is located on the 

plains of Oklahoma or in the Colorado mountains. However, 

for heliports located farther than 3 NM from the heliport, Part

135 HEMS operators are held to an even higher standard and 

the minimums and lighting conditions contained in Figure 

7-15 apply to the entire route. Mountainous terrain at night 

with low light conditions requires a ceiling of 1,000 feet and 

either 3 SM or 5 SM visibility depending on whether it has 

been determined as part of the operator’s local flying area.

In Class B, C, D, and E surface area airspace, a SVFR clearance 

may be obtained if SVFR minimums exist. On your flight plan, 

give ATC a heads up about your intentions by entering the 

following in the remarks section: “Request SVFR clearance 

after the MAP.”

Approach to a Specific VFR Heliport 

The note associated with these procedures is: “PROCEED 

VISUALLY FROM (NAMED MAP) OR CONDUCT THE 

SPECIFIED MISSED APPROACH.” Due to their unique 

characteristics, these approaches require training. They are 

developed for hospitals, oil rigs, private heliports, etc. As 

Specials, they require Flight Standards approval by a Letter 

of Authorization (LOA) for Part 91 operators or by OpSpecs 

for Part 135 operators. The heliport associated with these 

procedures must be located within 10,560 feet of the MAP, 

the visual segment between the MAP and the heliport 

evaluated for obstacle hazards, and the heliport must meet 

the appropriate VFR heliport recommendations of AC

150/5390-2, “Heliport Design.”

The PinS optimum location is 0.65 NM from the heliport. 

This provides an adequate distance to decelerate and 

land from an approach speed of 70 KIAS. Certain airframes 

may be certified to fly at reduced VMINI or below VMINI 

speeds as a result of flight control design or adherence to 

AC 29-2, “Certification of Transport Category Rotorcraft.” In 

these cases, an approach procedure stating the minimum 

certified airspeed or flight below VMINI should be 

annotated on the approach procedure. The distance also 

permits optimal blending of obstacle clearance criteria with 

non-instrument heliport approach areas.

The visibility minimum is based on the distance from the 

MAP to the heliport, among other factors (e.g., height 

above the heliport elevation when at the MAP MDA). The 

pilot is required to acquire and maintain visual contact 
7-15

Figure 7-13. COPTER RNAV (GPS) 250° at New York/La Guardia Airport.

NE-2, 23 AUG 2012 to 20 SEP 2012

NE-2, 23 AUG 2012 to 20 SEP 2012
7-16

Figure 7-14. Weather minimums and lighting conditions for HEMS operators. 

Condition

Area Local

 500-2

 500-3

1000-3

Cross Country

 800-3

 1000-3

 1000-5

Local

500-1

500-2

800-3

Day

Night—High Lighting Conditions

Night—Low Lighting Conditions

Cross Country

 800-2

 1000-3

 1000-5

Non-Mountainous

Ceiling-visibility

Mountainous (14 CFR Part 95)

Figure 7-15. Point-in-space (PinS) approach examples for Part 91 and Part 135 operations. 

Point-in-Space Approach Examples

Under Part 91, the operator flies the published IFR PinS approach procedure that has a charted MDA of 340 mean sea level (MSL) 

and visibility of 3⁄4 SM. When approaching the MAP at an altitude of 340 feet MSL, the pilot transitions from Instrument Meteorological 

Conditions (IMC) to Visual Meteorological Conditions (VMC) and determines that the flight visibility is 1⁄2 SM. The pilot must determine 

prior to the MAP whether the applicable basic VFR weather minimums can be maintained from the MAP to the heliport or execute a

missed approach. If the pilot determines that the applicable basic VFR weather minimums can be maintained to the heliport, the pilot 

may proceed VFR. If the visual segment is in Class B, C, D, or the surface area of Class E airspace, it may require the pilot to obtain 

a Special VFR clearance.

For an operator to proceed VFR under Part 135, a minimum visibility of 1⁄2 SM during the day and 1 SM at night with a minimum 

ceiling of 300 feet. If prior to commencing the approach, the pilot determines the reported visibility is 3⁄4 SM during the day, the pilot 

descends IMC to an altitude no lower than the MDA and transitions to VMC. If the pilot determines prior to the MAP that the flight 

visibility is less than 1⁄2 SM in the visual segment, a missed approach must be executed at the MAP.

EXAMPLE 1

EXAMPLE 2

with the heliport final approach and takeoff (FATO) area 

at or prior to the MAP. Obstacle or terrain avoidance from 

the MAP to the heliport is the responsibility of the pilot. 

Pilots need to level off when reaching the MDA, which 

may occur before arriving at the MAP, until reaching the 

visual approach angle on the approach path to clear the 

obstacles. If the required weather minimums do not exist, 

then the published MAP must be executed at the MAP 

because IFR obstruction clearance areas are not applied to 

the visual segment of the approach and a missed approach 

segment protection is not provided between the MAP 

and the heliport. As soon as practicable after reaching 

the MAP, the pilot advises ATC whether cancelling IFR and 

proceeding visually or executing the missed approach.

Inadvertent IMC

Whether it is a corporate or HEMS operation, helicopter pilots 

sometimes operate in challenging weather conditions. An 

encounter with weather that does not permit continued 

flight under VFR might occur when conditions do not allow 

for the visual determination of a usable horizon (e.g., fog, 

snow showers, or night operations over unlit surfaces such 

as water). Flight in conditions of limited visual contrast 

should be avoided since this can result in a loss of horizontal 

or surface reference, and obstacles such as wires become 

perceptually invisible. To prevent spatial disorientation, loss 

of control (LOC) or CFIT, pilots should slow the helicopter to a 

speed that provides a controlled deceleration in the distance 

equal to the forward visibility. The pilot should look for terrain 

that provides sufficient contrast to either continue the flight 

or to make a precautionary landing. If spatial disorientation 

occurs and a climb into IMC is not feasible due to fuel state, 

icing conditions, equipment, etc., make every effort to land 

the helicopter with a slight forward descent to prevent any 

sideward or rearward motion.

All helicopter pilots should receive training on avoidance 

and recovery from inadvertent IMC with emphasis on 

avoidance. An unplanned transition from VFR to IFR flight 

is an emergency that involves a different set of pilot actions. 

It requires the use of different navigation and operational 

procedures, interaction with ATC, and crewmember resource 
7-17

management (CRM). Consideration should be given to the 

local flying area’s terrain, airspace, air traffic facilities, weather 

(including seasonal affects such as icing and thunderstorms), 

and available airfield/heliport approaches.

Training should emphasize the identification of 

circumstances conducive to inadvertent IMC and a 

strategy to abandon continued VFR flight in deteriorating 

conditions. This strategy should include a minimum 

altitude/airspeed combination that provides for an offairport/heliport landing, diverting to better conditions, 

or initiating an emergency transition to IFR. Pilots should 

be able to readily identify the minimum initial altitude 

and course in order to avoid CFIT. Current IFR en route 

and approach charts for the route of flight are essential. 

A GPS navigation receiver with a moving map provides 

exceptional situational awareness for terrain and obstacle 

avoidance.

Training for an emergency transition to IFR should 

include full and partial panel instrument flight, unusual 

attitude recovery, ATC communications, and instrument 

approaches. If an ILS is available and the helicopter is 

equipped, an ILS approach should be made. Otherwise, if 

the helicopter is equipped with an IFR approach-capable 

GPS receiver with a current database, a GPS approach 

should be made. If neither, an ILS or GPS procedure is 

available use another instrument approach.

Upon entering inadvertent IMC, priority must be given 

to control of the helicopter. Keep it simple and take one 

action at a time.

• 	 Control. First use the wings on the attitude indicator

to level the helicopter. Maintain heading and 

increase to climb power. Establish climb airspeed at 

the best angle of climb but no slower than VMINI.

•	 Climb. Climb straight ahead until your crosscheck is

established. Then make a turn only to avoid terrain 

or objects. If an altitude has not been previously 

established with ATC to climb to for inadvertent IMC, 

then you should climb to an altitude that is at least 

1,000 feet above the highest known object and that 

allows for contacting ATC.

•	 Communicate. Attempt to contact ATC as soon as

the helicopter is stabilized in the climb and headed 

away from danger. If the appropriate frequency is 

not known, you should attempt to contact ATC on 

either very high frequency (VHF) 121.5 or ultra high 

frequency (UHF) 243.0. Initial information provided 

to ATC should be your approximate location, that 

inadvertent IMC has been encountered and an 

emergency climb has been made, your altitude, 

amount of flight time remaining (fuel state), and 

number of persons on board. You should then 

request a vector to either VFR weather conditions 

or to the nearest suitable airport/heliport that 

conditions will support a successful approach. If 

unable to contact ATC and a transponder code 

has not been previously established with ATC for 

inadvertent IMC, change the transponder code to 

7700.

A radio altimeter is a necessity for alerting the pilot 

when inadvertently going below the minimum altitude. 

Barometric altimeters are subject to inaccuracies that 

become important in helicopter IFR operations, especially 

in cold temperatures.

IFR Heliports 

A C 1 5 0 / 5 3 9 0 - 2 , “ H e l i p o r t D e s i g n ,” p r o v i d e s 

recommendations for heliport design to support nonprecision, approach with vertical guidance (APV), and 

precision approaches to a heliport. When a heliport does 

not meet the criteria of this AC, FAA Order 8260.42, United 

States Standard for Helicopter Area Navigation (RNAV), 

requires that an instrument approach be published as a 

SPECIAL procedure with annotations that special aircrew 

qualifications are required to fly the procedure. Currently, 

there are no operational civil IFR heliports in the U.S., 

although the U.S. military has some non-precision and 

precision approach procedures to IFR heliports.
7-18
A-1

Introduction 

Changing weather conditions, air traffic control (ATC), aircraft, and pilots are variables that make instrument flying an 

unpredictable and challenging operation. Safety of the flight depends on the pilot’s ability to manage these variables 

while maintaining positive aircraft control and adequate situational awareness (SA). This appendix discusses recognition 

and suggested remedies for emergency events related to un-forecasted, adverse weather, aircraft system malfunctions, 

communication/navigation system malfunctions, loss of SA, and inadvertent instrument meteorological conditions 

(IIMCs).

Emergencies 

An emergency can be either a distress or urgency condition as defined in the pilot/controller glossary. Distress is defined 

as a condition of being threatened by serious and/or imminent danger and requiring immediate assistance. Urgency is 

defined as a condition of being concerned about safety and requiring timely but not immediate assistance; a potential 

distress condition.

Pilots do not hesitate to declare an emergency when faced with distress conditions, such as fire, mechanical failure, 

or structural damage. However, some are reluctant to report an urgency condition when encountering situations that 

may not be immediately perilous but are potentially catastrophic. An aircraft is in an urgency condition the moment 

that the pilot becomes doubtful about position, fuel endurance, weather, or any other condition that could adversely 

affect flight safety. After the situation has developed into a distress condition is not the time to be requesting help.

The pilot in command (PIC) is responsible for crew, passengers, and operation of the aircraft at all times. Title 14 of the 

Code of Federal Regulations (14 CFR) part 91, section 91.3 allows deviations from regulations during emergencies that 

allow the PIC to make the best decision to ensure safety of all personnel during these contingencies. Also, by declaring 

an emergency during flight, that aircraft becomes a priority to land safely. Pilots who become apprehensive for their 

safety for any reason should request assistance immediately. Assistance is available in the form of radio, radar, direction 

finding (DF) stations, and other aircraft.

Inadvertent Thunderstorm Encounter

A pilot should always avoid intentionally flying through a thunderstorm of any intensity; however, certain conditions may 

be present that could lead to an inadvertent thunderstorm encounter. For example, flying in areas where thunderstorms 

are embedded in large cloud masses may make thunderstorm avoidance difficult, even when the aircraft is equipped 

with thunderstorm detection equipment. Pilots must be prepared to deal with inadvertent thunderstorm penetration. 

At the very least, a thunderstorm encounter subjects the aircraft to turbulence that could be severe. The pilot, as well 

as the crew and any passengers, should tighten seat belts and shoulder harnesses and secure any loose items in the 

cabin or flight deck.

As with any emergency, the first order of business is to fly the aircraft. The pilot workload is high; therefore, increased 

concentration is necessary to maintain an instrument scan. Once in a thunderstorm, it is better to maintain a course 

straight through the thunderstorm rather than turning around. A straight course most likely gets the pilot out of the 

hazard in the least amount of time, and turning maneuvers only increase structural stress on the aircraft.

Reduce power to a setting that maintains a recommended turbulence penetration speed as described in the appropriate 

aircraft operator’s manual, and try to minimize additional power adjustments. Concentrate on keeping the aircraft in 

Emergency Procedures 

Appendix A
A-2

a level attitude while allowing airspeed and altitude to fluctuate. Similarly, if using autopilot, disengage altitude and 

speed hold modes because they only increase the aircraft’s maneuvering, which increases structural stress.

During a thunderstorm encounter, the potential for icing also exists. As soon as possible, if the aircraft is so equipped, 

turn on anti-icing/deicing equipment. Icing can be rapid at any altitude, and may lead to power failure and/or loss of 

airspeed indication. Lightning is also present in a thunderstorm and can temporarily blind the pilot. To reduce risk, 

turn up flight deck lights to the highest intensity, concentrate on flight instruments, and resist the urge to look outside.

Inadvertent Icing Encounter

Because icing is unpredictable, pilots may find themselves in icing conditions although they have done everything to 

avoid the condition. To stay alert to this possibility while operating in visible moisture, pilots should monitor the outside 

air temperature (OAT).

Anti-icing/deicing equipment is critical to safety of the flight. If anti-icing/deicing equipment is not used before sufficient 

ice has accumulated, it may not be able to remove all ice accumulation. Use of anti-icing/deicing reduces power 

availability; therefore, pilots should be familiar with the aircraft operator’s manual for use of anti-icing/deicing equipment.

Before entering visible moisture with temperatures at five degrees above freezing or cooler, activate appropriate 

anti-icing/ deicing equipment in anticipation of ice accumulation; early ice detection is critical. Detecting ice may be 

particularly difficult during night flight. The pilot may need to use a flashlight to check for ice accumulation on the 

wings, fuselage, landing gear, and horizontal stabilizer. At the first indication of ice accumulation, the pilot must act 

to circumvent icing conditions. Options for action once ice has begun to accumulate on the aircraft are the following:

•	 Move to an altitude with significantly colder temperatures.

•	 Move to an altitude with temperatures above freezing.

•	 Fly to an area clear of visible moisture.

•	 Change the heading, and fly to an area of known non-icing conditions.

If these options are not available, consider an immediate landing at the nearest suitable airport. Anti-icing/deicing 

equipment does not allow aircraft to operate in icing conditions indefinitely; it only provides more time to evade icing 

conditions. If icing is encountered, an aircraft controllability check should be considered in the landing configuration. 

Give careful consideration to configuration changes that might produce unanticipated aircraft flight dynamics.

Precipitation Static

Precipitation static occurs when accumulated static electricity discharges from extremities of the aircraft. This discharge 

has the potential to create problems with the aircraft’s instruments. These problems range from serious, such as 

complete loss of VHF communications and erroneous magnetic compass readings, to the annoyance of high-pitched 

audio squealing.

Precipitation static is caused when an aircraft encounters airborne particles during flight (rain or snow) and develops a 

negative charge. It can also result from atmospheric electric fields in thunderstorm clouds. When a significant negative 

voltage level is reached, the aircraft discharges it, creating electrical disturbances. To reduce problems associated with 

precipitation static, the pilot ensures that the aircraft’s static wicks are maintained and accounted for. All broken or 

missing static wicks should be replaced before an instrument flight.

Aircraft System Malfunction

Preventing aircraft system malfunctions that might lead to an in-flight emergency begins with a thorough preflight 

inspection. In addition to items normally checked before visual flight rules (VFR) flight, pilots intending to fly instrument 

flight rules (IFR) should pay particular attention to antennas, static wicks, anti-icing/deicing equipment, pitot tube, and 

static ports. During taxi, verify operation and accuracy of all flight instruments. The pilots must ensure that all systems 

are operational before departing into IFR conditions.
A-3

Generator Failure

Depending on aircraft being flown, a generator failure is indicated in different ways. Some aircraft use an ammeter 

that indicates the state of charge or discharge of the battery. A positive indication on the ammeter indicates a charge 

condition; a negative indication reveals a discharge condition. Other aircraft use a load meter to indicate the load being 

carried by the generator. If the generator fails, a zero load indication is shown on the load meter. Review the appropriate 

aircraft operator’s manual for information on the type of systems installed in the aircraft.

Once a generator failure is detected, the pilot must reduce electrical load on the battery and land as soon as practical. 

Depending on electrical load and condition of the battery, sufficient power may be available for an hour or more of 

flight or for only a matter of minutes. The pilot must be familiar with systems requiring electricity to run and which 

continue to operate without power. In aircraft with multiple generators, care should be taken to reduce electrical load 

to avoid overloading the operating generator(s). The pilot can attempt to troubleshoot generator failure by following 

established procedures published in the appropriate aircraft operator’s manual. If the generator cannot be reset, inform 

ATC of an impending electrical failure.

Instrument Failure

System or instrument failure is usually identified by a warning indicator or an inconsistency between indications on 

the attitude indicator, supporting performance instruments, and instruments at the other pilot station, if so equipped. 

Aircraft control must be maintained while the pilot identifies the failed components and expedite cross-check including 

all flight instruments. The problem may be individual instrument failure or a system failure affecting several instruments.

One method of identification involves an immediate comparison of the attitude indicator with rate-of-turn indicator 

and vertical speed indicator (VSI). Along with providing pitch-and-bank information, this technique compares the static 

system with the pressure system and electrical system. Identify the failed components and use remaining functional 

instruments to maintain aircraft control. Attempt to restore inoperative components by checking the appropriate power 

source, changing to a backup or alternate system, and resetting the instrument if possible. Covering failed instruments 

may enhance the ability to maintain aircraft control and navigate the aircraft. ATC should be notified of the problem 

and, if necessary, declare an emergency before the situation deteriorates beyond the ability to recover.

Pitot/Static System Failure

A pitot or static system failure can also cause erratic and unreliable instrument indications. When a static system 

problem occurs, it affects the airspeed indicator, altimeter, and VSI. In the absence of an alternate static source in an 

unpressurized aircraft, the pilot could break the glass on the VSI because it is not required for instrument flight. Breaking 

the glass provides both the altimeter and airspeed indicator a source of static pressure, but pilots should be cautious 

because breaking the glass can cause additional instrument errors. Before considering, pilots should be familiar with 

their aircraft’s specific procedures for static problems.

Loss of Situational Awareness (SA)

SA is an overall assessment of environmental elements and how they affect flight. SA permits the pilot to make decisions 

ahead of time and allows evaluation of several different options. Conversely, a pilot who is missing important information 

about the flight is apt to make reactive decisions. Poor SA means that the pilot lacks vision regarding future events 

that can force him or her to make decisions quickly often with limited options. During an IFR flight, pilots operate at 

varying levels of SA. For example, a pilot may be en route to a destination with a high level of SA when ATC issues an 

unexpected standard terminal arrival route (STAR). Because the STAR is unexpected and the pilot is unfamiliar with the 

procedure, SA is reduced. However, after becoming familiar with the STAR and resuming normal navigation, the pilot 

returns to a higher level of SA.

Factors reducing SA include distractions, unusual or unexpected events, complacency, high workload, unfamiliar 

situations, and inoperative equipment. In some situations, a loss of SA may be beyond a pilot’s control. With an electrical 

system failure and associated loss of an attitude indication, a pilot may find the aircraft in an unusual attitude. In this 

situation, established procedures are used to regain SA. Pilots must be alert to loss of SA especially when hampered by 
A-4

a reactive mindset. To regain SA, reassess the situation and work toward understanding what the problem is. The pilot 

may need to seek additional information from other sources, such as navigation instruments, other crewmembers, or ATC.

Inadvertent Instrument Meteorological Condition (IIMC)

Some pilots have the misconception that inadvertent instrument meteorological condition (IIMC) does not apply to an IFR

flight. The following examples could cause a pilot to inadvertently encounter IMC.

1. The aircraft has entered visual meteorological conditions (VMC) during an instrument approach procedure

 (IAP) and while circling to land encounters IMC.

2. During a non-precision IAP, the aircraft, in VMC, levels at the MDA just below the overcast. Suddenly, the 

 aircraft re-enters the overcast because either the pilot was unable to correctly hold his or her altitude and 

 climbed back into the overcast, or the overcast sloped downward ahead of the aircraft and, while maintaining

 the correct MDA, the aircraft re-entered the clouds.

In order to survive an encounter with IIMC, a pilot must recognize and accept the seriousness of the situation. The pilot 

will need to immediately commit to the instruments and perform the proper recovery procedures.

Maintaining Aircraft Control

Once the crewmembers recognize the situation, they commit to controlling the aircraft by using and trusting flight 

instruments. Attempting to search outside the flight deck for visual confirmation can result in spatial disorientation 

and complete loss of control. The crew must rely on instruments and depend on crew coordination to facilitate that 

transition. The pilot or flight crew must abandon their efforts to establish visual references and fly the aircraft by their 

flight instruments.

The most important concern, along with maintaining aircraft control, is to initiate a climb immediately. An immediate 

climb provides a greater separation from natural and manmade obstacles, as well as improve radar reception of the 

aircraft by ATC. An immediate climb should be appropriate for the current conditions, environment, and known or 

perceived obstacles. Listed below are procedures that can assist in maintaining aircraft control after encountering IIMC 

with the most critical action being to immediately announce IIMC and begin a substantial climb while procedures are 

being performed. These procedures are performed nearly simultaneously:

•	 Attitude—level wings on the attitude indicator.

•	 Heading—maintain heading; turn only to avoid known obstacles.

•	 Power—adjust power as necessary for desired climb rate.

•	 Airspeed—adjust airspeed as necessary. Complete the IIMC recovery according to local and published 	 	

regulations and policies.

In situations where the pilot encounters IIMC while conducting an instrument maneuver, the best remedy is immediate 

execution of the published missed approach.

The pilot must trust the flight instruments concerning the aircraft’s attitude regardless of intuition or visual interpretation. 

The vestibular sense (motion sensing by the inner ear) can confuse the pilot. Because of inertia, sensory areas of the 

inner ear cannot detect slight changes in aircraft attitude nor can they accurately sense attitude changes that occur at 

a uniform rate over time. Conversely, false sensations often push the pilot to believe that the attitude of the aircraft has 

changed when in fact it has not, resulting in spatial disorientation. 

ATC Requirements During an In-Flight Emergency

ATC personnel can help pilots during in-flight emergency situations. Pilots should understand the services provided 

by ATC and the resources and options available. These services enable pilots to focus on aircraft control and help them 

make better decisions in a time of stress.
A-5

Provide Information

During emergency situations, pilots should provide as much information as possible to ATC. ATC uses the information to 

determine what kind of assistance it can provide with available assets and capabilities. Information requirements vary 

depending on the existing situation. ATC requires at a minimum, the following information for in-flight emergencies:

•	 Aircraft identification and type

•	 Nature of the emergency

•	 Pilot’s desires

If time and the situation permits, the pilot should provide ATC with more information. Listed below is additional 

information that would help ATC in further assisting the pilot during an emergency situation. 

•	 Aircraft altitude

•	 Point of departure and destination

•	 Airspeed

•	 Fuel remaining in time

•	 Heading since last known position

•	 Visible landmarks

•	 Navigational aids (NAVAID) signals received

•	 Time and place of last known position

•	 Aircraft color

•	 Pilot reported weather

•	 Emergency equipment on board

•	 Number of people on board

•	 Pilot capability for IFR flight

•	 Navigation equipment capability

When the pilot requests, or when deemed necessary, ATC can enlist services of available radar facilities and DF facilities 

operated by the FAA. ATC can also coordinate with other agencies, such as the Federal Communications Commission 

(FCC) and other local authorities and request their emergency services.

Radar Assistance

Radar is an invaluable asset that can be used by pilots during emergencies. With radar, ATC can provide navigation 

assistance to aircraft and provide last-known location during catastrophic emergencies. If a VFR aircraft encounters or 

is about to encounter IMC weather conditions, the pilot can request radar vectors to VFR airports or VFR conditions. If 

the pilot determines that he or she is qualified and the aircraft is capable of conducting IFR flight, the pilot should file 

an IFR flight plan and request a clearance from ATC to the destination airport as appropriate. If the aircraft has already 

encountered IFR conditions, ATC can inform the pilot of appropriate terrain/obstacle clearance minimum altitude. If the 

aircraft is below appropriate terrain/obstacle clearance minimum altitude and sufficiently accurate position information 

has been received or radar identification is established, ATC can furnish a heading or radial on which to climb to reach 

appropriate terrain/ obstacle clearance minimum altitude.

Emergency Airport 

ATC personnel consider how much remaining fuel in relation to the distance to the airport and weather conditions 

when recommending an emergency airport to aircraft requiring assistance. Depending on the nature of the emergency, 

certain weather phenomena may deserve weighted consideration. A pilot may elect to fly further to land at an airport 

with VFR conditions instead of closer airfield with IFR conditions. Other considerations are airport conditions, NAVAID 

status, aircraft type, pilot’s qualifications, and vectoring or homing capability to the emergency airport. In addition, 

ATC and pilots should determine which guidance can be used to fly to the emergency airport. The following options 
A-6

may be available: 

•	 Radar

•	 DF

•	 Following another aircraft

•	 NAVAIDs

•	 Pilotage by landmarks

•	 Compass headings

Emergency Obstruction Video Map (EOVM)

The emergency obstruction video map (EOVM) is intended to facilitate advisory service in an emergency situation when 

appropriate terrain/obstacle clearance minimum altitude cannot be maintained. The EOVM, and the service provided, 

are used only under the following conditions: 

1. The pilot has declared an emergency.

2. The controller has determined an emergency condition exists or is imminent because of the pilots inability to 

maintain an appropriate terrain/obstacle clearance minimum altitude. 

NOTE: Appropriate terrain/obstacle clearance minimum altitudes may be defined as minimum IFR altitude (MIA), minimum

en route altitude (MEA), minimum obstacle clearance altitude (MOCA), or minimum vectoring altitude (MVA).

When providing emergency vectoring service, the controller advises the pilot that any headings issued are emergency 

advisories intended only to direct the aircraft toward and over an area of lower terrain/obstacle elevation. Altitudes and 

obstructions depicted on the EOVM are actual altitudes and locations of the obstacle/terrain and contain no lateral or 

vertical buffers for obstruction clearance.

Responsibility

ATC, in communication with an aircraft in distress, should handle the emergency and coordinate and direct the activities 

of assisting facilities. ATC will not transfer this responsibility to another facility unless that facility can better handle the 

situation. When an ATC facility receives information about an aircraft in distress, they forward detailed data to the center 

in the area of the emergency. Centers serve as central points for collecting information, coordinating with search and 

rescue (SAR) and distributing information to appropriate agencies.

Although 121.5 megahertz and 243.0 megahertz are emergency frequencies, the pilot should keep the aircraft on the 

initial contact frequency. The pilot should change frequencies only when a valid reason exists. When necessary, and 

if weather and circumstances permit, ATC should recommend that aircraft maintain or increase altitude to improve 

communications, radar, or DF reception.

Escort 

An escort aircraft, if available, should consider and evaluate an appropriate formation. Special consideration must be 

given if maneuvers take the aircraft through clouds. Aircraft should not execute an in-flight join up during emergency 

conditions unless both crews involved are familiar with and capable of formation flight and can communicate and have 

visual contact with each other.
B-1

A

AAC—Aircraft Administration Communications

AAUP—Attention All Users Page

AC—Advisory Circular

ACARS—Aircraft Communications Addressing and Reporting System

ADCs—Air Data Computers 

ADDS—Aviation Digital Data Services 

ADF—Automatic Direction Finder 

ADS—Automatic Dependent Surveillance

ADS-B—Automatic Dependent Surveillance-Broadcast 

AEG—Aircraft Evaluation Group 

A/FD—Airport/Facility Directory

AFM—Airplane Flight Manual or Aircraft Flight Manual 

AFMS—Airplane Flight Manual Supplements 

AFS—Aircraft Flight Safety

AFS—Flight Standards Service

AFSS—Automated Flight Service Station 

AGL—Above Ground Level 

AIM—Aeronautical Information Manual 

AIP—Aeronautical Information Publication 

AIR—Aircraft Certification Service

AIRMETs—Airman’s Meteorological Information

AJV-3—Aeronautical Navigation Products

AJW-3—Flight Inspection Services

ALT ACQ—Altitude Acquire 

ALT Hold—Altitude Hold 

ANP—Actual Navigation Performance

AOC—Aircraft Operational Communications 

APT WP—Airport Waypoint 

APV—Approach with Vertical Guidance 

ARINC—Aeronautical Radio Incorporated

A-RNAV—Advanced Area Navigation 

ARTCC—Air Route Traffic Control Center 

ARTS—Automated Radar Terminal System 

ASDA—Accelerate-Stop Distance Available

ASDE-X—Airport Surface Detection Equipment-Model X

A-SMGCS—Advanced Surface Movement Guidance and Control System

ASOS—Automated Surface Observing System 

ASR—Airport Surveillance Radar 

ASRS—Aviation Safety Reporting System 

ATA—Air Transport Association

ATC—Air Traffic Control

ATCAA—Air Traffic Control Assigned Airspace 

ATCRBS—Air Traffic Control Radar Beacon System 

Acronyms

Appendix B
B-2

ATCS—Air Traffic Control Specialist 

ATD—Along-Track Distance

ATIS—Automatic Terminal Information Service

ATS—Air Traffic Service 

AWC—Aviation Weather Center 

AWOS—Automated Weather Observing System 

AWSS—Automated Weather Sensor System

B

Baro-VNAV—Barometric Vertical Navigation

B-RNAV—European Basic RNAV

C

CAT—Category

CDI—Course Deviation Indicator 

CDL—Configuration Deviation List 

CENRAP—Center Radar ARTS Processing 

CFA—Controlled Firing Areas 

CFIT—Controlled Flight Into Terrain 

CFR—Code of Federal Regulations 

CNF—Computer Navigation Fix 

COP—Changeover Point 

COTS—Commercial Off-The-Shelf 

CRC—Cyclic Redundancy Check 

CTAF—Common Traffic Advisory Frequency 

CVFP—Charted Visual Flight Procedure 

CWAS—Center Weather Advisories

D

DA—Density Altitude; Decision Altitude

D-ATIS—Digital Automatic Terminal Information Service

DDA—Derived Decision Altitude 

DEM—Digital Elevation Model 

DER—Departure End of the Runway 

DF—Direction Finding 

DH—Decision Height

DME—Distance Measuring Equipment 

DOD—Department of Defense 

DOT—Department of Transportation 

DPs—Departure Procedures

DRVSM—Domestic Reduced Vertical Separation Minimums 

DUATS—Direct User Access Terminal System 

DVA—Diverse Vector Area

E

E/D—End of Decent

EDCT—Expect Departure Clearance Time 

EFAS—En-Route Flight Advisory Service 

EFB—Electronic Flight Bag

EFC—Expect Further Clearance 

EFV—Enhanced Flight Visibility 
B-3

EFVS—Enhanced Flight Vision System

EGPWS—Enhanced Ground Proximity Warning Systems

EOPs—Engine Out Procedures

EOVM—Emergency Obstruction Video Map 

ER-OPS—Extended Range Operations 

ETA—Estimated Time of Arrival 

EV—Enhanced Vision

EVO—Equivalent Visual Operations

EWINS—Enhanced Weather Information System

F

FAA—Federal Aviation Administration

FAF—Final Approach Fix 

FAP—Final Approach Point 

FB—Fly-By

FBWP—Fly-By Waypoint

FCC—Federal Communications Commission

FD—Flight Director 

FDP—Flight Data Processing 

FE—Flight Engineer 

FIR—Flight Information Region 

FIS—Flight Information System

FIS-B—Flight Information Services–Broadcast 

FISDL—Flight Information Services Data Link 

FL—Flight Level

FL CHG—Flight Level Change 

FLIR—Forward Looking Infra-Red

FMC—Flight Management Computer 

FMS—Flight Management System 

FO—Fly-Over

FOM—Flight Operations Manual 

FOWP—Fly-Over Waypoint 

FPA—Flight Path Angle 

FPM—Feet Per Minute 

FPNM—Feet Per Nautical Mile 

FPV—Flight Path Vector

FSB—Flight Standardization Board 

FSDO—Flight Standards District Office 

FSL—NOAA Forecast Systems Laboratory 

FSS—Flight Service Station

G

GBAS—Ground-Based Augmentation System 

GCA—Ground Controlled Approach 

GCO—Ground Communication Outlet 

GDP—Ground Delay Programs 

GDPE—Ground Delay Program Enhancements

GLS—Global Navigation Satellite System Landing System

GNSS—Global Navigation Satellite System GPS—Global Positioning System 

GPWS—Ground Proximity Warning System G/S—Glide Slope

GS—Ground Speed
B-4

GWS—Graphical Weather Service

H

HAA—Height Above Airport 

HAR—High Altitude Redesign 

HAT—Height Above Touchdown 

HAZMAT—Hazardous Materials 

HDD—Head-Down Display 

HF—High Frequency

HGS—Head-up Guidance System

HIWAS—Hazardous In-flight Weather Advisory Service

HSI—Horizontal Situation Indicator

HUD—Head-Up Display

I

IAF—Initial Approach Fix 

IAP—Instrument Approach Procedure 

IAS—Indicated Air Speed

ICAO—International Civil Aviation Organization

IF—Intermediate Fix

IFR—Instrument Flight Rules

IIMC—Inadvertent Instrument Meteorological Condition

ILS—Instrument Landing System 

IMC—Instrument Meteorological Conditions 

INS—Inertial Navigation System 

IOC—Initial Operational Capability 

IRU—Inertial Reference Unit

K

KIAS—knots indicated airspeed 

KLAX—Los Angeles International Airport 

KLMU—Monroe Regional Airport

L

LAAS—Local Area Augmentation System

LAHSO—Land And Hold Short Operations

LDA—Localizer-type Directional Aid; Landing Distance Available

LF—Low Frequency 

LNAV—Lateral Navigation 

LOC—Localizer 

LOM—Locator Outer Marker

LPV—Localizer Performance with Vertical Guidance

LTP—Landing Threshold Point

LVL CHG—Level Change

M

MAA—Maximum Authorized Altitude 

MAHWP—Missed Approach Holding Waypoint 

MAMS—Military Airspace Management System 

MAP—Missed Approach Point
B-5

MAWP—Missed Approach Waypoint

MCA—Minimum Crossing Altitude

MDA—Minimum Descent Altitude 

MDH—Minimum Descent Height 

MEA—Minimum En-route Altitude 

MEL—Minimum Equipment List 

METAR—Aviation Routine Weather Report 

MF—Medium Frequency

MIA—Minimum IFR Altitude 

MLS—Microwave Landing System 

MMWR—Millimeter Wave Radar

MNPS—Minimum Navigation Performance Specifications

MOA—Military Operations Area 

MOCA—Minimum Obstruction Clearance Altitude 

MOPS—Minimum Operational Performance Standards 

MORA—Minimum Off-Route Altitude 

MRA—Minimum Reception Altitude

MSA—Minimum Safe Altitude 

MSAW—Minimum Safe Altitude Warning 

MSL—Mean Sea Level

MTA—Minimum Turning Altitude 

MTR—Military Training Route 

MVA—Minimum Vectoring Altitude N

NA—Not Authorized

NACO—National Aeronautical Charting Office

NAS—National Airspace System

NASA—National Aeronautics and Space Administration

NAT—North Atlantic

NAVAID—Navigational Aid

NCAR—National Center for Atmospheric Research

NDB—Non-Directional Beacon

NextGen—Next Generation Air Transportation System

NFDC—National Flight Data Center

NFPO—National Flight Procedures Office 

NGA—National Geospatial- Intelligence Agency 

NM—Nautical Mile

NMAC—Near Mid-Air Collision 

NNEW—Next Generation Network-Enabled 

NOAA—National Oceanic and Atmospheric Administration 

NO A/G—No Air-to-Ground Communication

NOPAC—North Pacific 

NOTAM—Notice to Airmen 

NOZ—Normal Operating Zone

NPA—Non-Precision Approach 

NRR—Non-Restrictive Routing 

NRS—National Reference System 

NTAP—Notice to Airmen Publication

NTSB—National Transportation Safety Board

NTZ—No Transgression Zone 
B-6

NVS—NAS voice switch 

NWS—National Weather Service

O

OAT—Outside Air Temperature 

OBS—Omni Bearing Selector 

OCS—Obstacle Clearance Surface 

ODP—Obstacle Departure Procedure 

OpSpecs—Operations Specifications

OROCA—Off-Route Obstruction Clearance Altitude

OSV—Operational Service Volume

P

PA—Precision Approach 

PAR—Precision Approach Radar 

PCG—Positive Course Guidance 

PDC—Pre-Departure Clearance 

PDR—Preferential Departure Route 

PF—Pilot Flying

PFD—Primary Flight Display 

PI—Principal Inspector 

PIC—Pilot In Command 

PIREP—Pilot Weather Report

PKI—Public/Private Key Technology

PM—Pilot Monitoring 

POH—Pilot’s Operating Handbook 

POI—Principle Operations Inspector 

PRM—Precision Runway Monitor

P-RNAV—European Precision RNAV

PT—Procedure Turn

PTP—Point-To-Point

Q

QFE—Transition Height 

QNE—Transition Level 

QNH—Transition Altitude

R

RA—Resolution Advisory; Radio Altitude

RAIM—Receiver Autonomous Integrity Monitoring 

RAL—Research Applications Laboratory 

RCO—Remote Communications Outlet

RJ—Regional Jet

RNAV—Area Navigation

RNP—Required Navigation Performance

RNP AR—Required Navigation Performance Authorization Required

ROC—Required Obstacle Clearance 

RSP—Runway Safety Program 

RVR—Runway Visual Range

RVSM—Reduced Vertical Separation Minimums

RVV—Runway Visibility Value
B-7

RWY—Runway

RWY WP—Runway Waypoint S

SA—Situational Awareness

SAAAR—Special Aircraft and Aircrew Authorization Required 

SAAR—Special Aircraft and Aircrew Requirements 

SAMS—Special Use Airspace Management System 

SAR—Search and Rescue

SAS—Stability Augmentation System 

SATNAV—Satellite Navigation 

SDF—Simplified Directional Facility 

SDR—Service Difficulty Reports 

SER—Start End of Runway

SIAP—Standard Instrument Approach Procedure 

SID—Standard Instrument Departure

SIGMET—Significant Meteorological Information 

SM—Statute Mile

SMA—Surface Movement Advisor

SMGCS—Surface Movement Guidance and Control System 

SOIA—Simultaneous Offset Instrument Approaches 

SOP—Standard Operating Procedure

SPECI—Non-routine (Special) Aviation Weather Report

SSV—Standard Service Volume

STAR—Standard Terminal Arrival

STARS—Standard Terminal Automation Replacement System

STC—Supplemental Type Certificate

SUA—Special Use Airspace

SUA/ISE—Special Use Airspace/In-flight Service Enhancement

SVFR—Special Visual Flight Rules 

SVS—Synthetic Vision System 

SWAP—Severe Weather Avoidance Plan

SWIM—System Wide Information Management T

TA—Traffic Advisory 

TAA—Terminal Arrival Area 

TACAN—Tactical Air Navigation 

TAF—Terminal Aerodrome Forecast 

TAS—True Air Speed

TAWS—Terrain Awareness and Warning Systems

TB—Track Bar

TCAS—Traffic Alert and Collision Avoidance System

TCH—Threshold Crossing Height 

TDLS—Terminal Data Link System 

TDZ—Touchdown Zone 

TDZE—Touchdown Zone Elevation 

TEC—Tower En-route Control

TERPS—U.S. Standard for Terminal Instrument Procedures

TFR—Temporary Flight Restriction

TIS-B—Traffic Information Service-Broadcast

TIBS—Telephone Information Briefing Service
B-8

TIS-B—Traffic Information Service-Broadcast

TIBS—Telephone Information Briefing Service

TOC—Top Of Climb 

TOD—Top Of Descent 

TODA—Takeoff Distance Available 

TOGA—Takeoff/Go Around 

TORA—Takeoff Runway Available

TPP—Terminal Procedures Publication 

TRACAB—Terminal Radar Approach Control in Tower Cab 

TSO—Technical Standard Order

TSOA—Technical Standing Order Authorization

U

UHF—Ultra High Frequency 

UNICOM—Universal Communications 

US—United States

USAF—United States Air Force

USDA—United States Department of Agriculture

V

VCOA—Visual Climb Over Airport / Airfield

VDA—Vertical Descent Angle 

VDP—Visual Descent Point 

VFR—Visual Flight Rules 

VGSI—Visual Glide Slope Indicator 

VHF—Very High Frequency 

VLJ—Very Light Jet

VMC—Visual Meteorological Conditions 

VMINI—Minimum Speed–IFR 

VNAV—Vertical Navigation

VNEI—Never-Exceed Speed-IFR

VSI—Vertical Speed Indicator

VOR—Very High-Frequency Omnidirectional Range

VORTAC—Very High Frequency Omnidirectional Range/Tactical Air Navigation

VOT—VOR Test Facility Signal 

VPA—Vertical Path Angle 

VREF—Reference Landing Speed 

V/S—Vertical Speed

VSO—Stalling Speed or the Minimum Steady Flight Speed in the Landing Configuration

W

WAAS—Wide Area Augmentation System 

WAC—World Aeronautical Chart 

WAM—Wide Area Multi-lateration 

WP—Waypoint

Z

ZFW—Fort Worth Air Route Traffic Control Center
G-1

Abeam Fix. A fix, NAVAID, point, or object positioned 

approximately 90 degrees to the right or left of the aircraft 

track along a route of flight. Abeam indicates a general 

position rather than a precise point.

Accelerate-Stop Distance Available (ASDA). The runway 

plus stopway length declared available and suitable for 

the acceleration and deceleration of an airplane aborting a 

takeoff.

Advanced Surface Movement Guidance and Control 

System (A-SMGCS). A system providing routing, guidance 

and surveillance for the control of aircraft and vehicles, 

in order to maintain the declared surface movement rate 

under all weather conditions within the aerodrome visibility 

operational level (AVOL) while maintaining the required 

level of safety.

Aircraft Approach Category. A grouping of aircraft based 

on reference landing speed (VREF), if specified, or if VREF is 

not specified, 1.3 VSO (the stalling speed or minimum steady 

flight speed in the landing configuration) at the maximum 

certificated landing weight.

Airport Diagram. A full-page depiction of the airport that 

includes the same features of the airport sketch plus 

additional details, such as taxiway identifiers, airport 

latitude and longitude, and building identification. Airport 

diagrams are located in the U.S. Terminal Procedures 

booklet following the instrument approach charts for a 

particular airport.

Airport/Facility Directory (A/FD). Regional booklets 

published by the Aeronautical Navigation Products branch 

(AJV-3) that provide textual information about all airports, 

both VFR and IFR. The A/FD includes runway length and 

width, runway surface, load bearing capacity, runway 

slope, airport services, and hazards, such as birds and 

reduced visibility.

Glossary

Airport Sketch. Depicts the runways and their length, width, 

and slope, the touchdown zone elevation, the lighting 

system installed on the end of the runway, and taxiways. 

Airport sketches are located on the lower left or right 

portion of the instrument approach chart.

Airpor t Sur face Detection Equipment-Model X 

(ASDE-X). Enables air traffic controllers to detect potential 

runway conflicts by providing detailed coverage of movement 

on runways and taxiways. By collecting data from a variety of 

sources, ASDE-X is able to track vehicles and aircraft on the 

airport movement area and obtain identification information 

from aircraft transponders.

Air Route Traffic Control Center (ARTCC). A facility 

established to provide air traffic control service to aircraft 

operating on IFR flight plans within controlled airspace and 

principally during the en route phase of flight

Air Traffic Service (ATS). Air traffic service is an ICAO 

generic term meaning variously, flight information service, 

alerting service, air traffic advisory service, air traffic control 

service (area control service, approach control service, or 

aerodrome control service).

Approach End of Runway (AER). The first portion of the 

runway available for landing. If the runway threshold is 

displaced, use the displaced threshold latitude/longitude 

as the AER.

Approach Fix. From a database coding standpoint, an 

approach fix is considered to be an identifiable point 

in space from the intermediate fix (IF) inbound. A fix 

located between the initial approach fix (IAF) and the IF is 

considered to be associated with the approach transition 

or feeder route.
G-2

Approach Gate. An imaginary point used by ATC to vector 

aircraft to the final approach course. The approach gate 

is established along the final approach course 1 NM from 

the final approach fix (FAF) on the side away from the 

airport and is located no closer than 5 NM from the landing 

threshold.

Area Navigation (RNAV). A method of navigation that 

permits aircraft operations on any desired course within 

the coverage of station referenced navigation signals or 

within the limits of self contained system capability.

Automated Surface Observing System (ASOS)/Automated 

Weather Sensor System (AWSS). The ASOS/AWSS is the 

primary surface weather observing system of the U.S.

Automated Surface Observing System (ASOS). A weather 

observing system that provides minute-by minute weather 

observations, such as temperature, dew point, wind, altimeter 

setting, visibility, sky condition, and precipitation. Some 

ASOS stations include a precipitation discriminator that can 

differentiate between liquid and frozen precipitation.

Automated Weather Observing System (AWOS). A suite 

of sensors that measure, collect, and disseminate weather 

data. AWOS stations provide a minute-by-minute update 

of weather parameters, such as wind speed and direction, 

temperature and dew point, visibility, cloud heights and types, 

precipitation, and barometric pressure. A variety of AWOS 

system types are available (from AWOS 1 to AWOS 3), each 

of which includes a different sensor array.

Automated Weather Sensor System (AWSS). The AWSS 

is part of the Aviation Surface Weather Observation Network 

suite of programs and provides pilots and other users 

with weather information through the Automated Surface 

Observing System. The AWSS sensor suite automatically 

collects, measures, processes, and broadcasts surface 

weather data. 

Automated Weather System. Any of the automated 

weather sensor platforms that collect weather data at 

airports and disseminate the weather information via 

radio and/or landline. The systems currently consist of the 

Automated Surface Observing System (ASOS), Automated 

Weather Sensor System (AWSS), and Automated Weather 

Observation System (AWOS).

Automatic Dependent Surveillance-Broadcast (ADS-B).

A surveillance system that continuously broadcasts GPS 

position information, aircraft identification, altitude, 

velocity vector, and direction to all other aircraft and air 

traffic control facilities within a specific area. Automatic 

dependent surveillance-broadcast (ADS-B) information 

is displayed in the flight deck via a flight deck display of 

traffic information (CDTI) unit, providing the pilot with 

greater situational awareness. ADS-B transmissions also 

provides controllers with a more complete picture of traffic 

and updates that information more frequently than other 

surveillance equipment.

Automatic Terminal Information Service (ATIS). A 

recorded broadcast available at most airports with an 

operating control tower that includes crucial information 

about runways and instrument approaches in use, specific 

outages, and current weather conditions, including visibility.

Center Radar ARTS Presentation/Processing (CENRAP).

CENRAP was developed to provide an alternative to a 

non-radar environment at terminal facilities should an ASR 

fail or malfunction. CENRAP sends aircraft radar beacon 

target information to the ASR terminal facility equipped 

with ARTS.

Changeover Point (COP). A COP indicates the point where 

a frequency change is necessary between navigation aids, 

when other than the midpoint on an airway, to receive 

course guidance from the facility ahead of the aircraft 

instead of the one behind. These COPs divide an airway 

or route segment and ensure continuous reception of 

navigational signals at the prescribed minimum en route 

IFR altitude.

Charted Visual Flight Procedure (CVFP). A CVFP may be 

established at some towered airports for environmental 

or noise considerations, as well as when necessary for the 

safety and efficiency of air traffic operations. Designed 

primarily for turbojet aircraft, CVFPs depict prominent 

landmarks, courses, and recommended altitudes to specific 

runways.

Cockpit Display of Traffic Information (CDTI). The display 

and user interface for information about air traffic within 

approximately 80 miles. It typically combines and shows 

traffic data from TCAS, TIS-B, and ADS-B. Depending on 
G-3

features, the display may also show terrain, weather, and 

navigation information.

Collision Hazard. A condition, event, or circumstance 

that could induce an occurrence of a collision or surface 

accident or incident. 

Columns. See database columns.

Contact Approach. An approach where an aircraft on an 

IFR flight plan, having an air traffic control authorization, 

operating clear of clouds with at least one mile flight 

visibility, and a reasonable expectation of continuing to 

the destination airport in those conditions, may deviate 

from the instrument approach procedure and proceed to 

the destination airport by visual reference to the surface. 

This approach is only authorized when requested by the 

pilot and the reported ground visibility at the destination 

airport is at least one statute mile.

Controlled Flight Into Terrain (CFIT). A situation where a 

mechanically normally functioning airplane is inadvertently 

flown into the ground, water, or an obstacle. There are 

two basic causes of CFIT accidents; both involve flight 

crew situational awareness. One definition of situational 

awareness is an accurate perception by pilots of the factors 

and conditions currently affecting the safe operation of the 

aircraft and the crew. The causes of CFIT are the flight crews’ 

lack of vertical position awareness or their lack of horizontal 

position awareness in relation to terrain and obstacles.

Database Columns. The spaces for data entry on each 

record. One column can accommodate one character. 

Database Field. The collection of characters needed to 

define one item of information.

Database Identifier. A specific geographic point in space 

identified on an aeronautical chart and in a naviation 

database, officially designated by the controlling state 

authority or derived by Jeppesen. It has no ATC function 

and should not be used in filing flight plans nor used when 

communicating with ATC.

Database Record. A single line of computer data made up 

of the fields necessary to define fully a single useful piece 

of data.

Decision Altitude (DA). A specified altitude in the precision 

approach at which a missed approach must be initiated 

if the required visual reference to continue the approach 

has not been established. The term “Decision Altitude (DA)” 

is referenced to mean sea level and the term “Decision 

Height (DH)” is referenced to the threshold elevation. Even 

though DH is charted as an altitude above MSL, the U.S. 

has adopted the term “DA” as a step toward harmonization 

of the United States and international terminology. At 

some point, DA will be published for all future instrument 

approach procedures with vertical guidance.

Decision Height (DH). See Decision Altitude.

Departure End of Runway (DER). The end of runway 

available for the ground run of an aircraft departure. The 

end of the runway that is opposite the landing threshold, 

sometimes referred to as the stop end of the runway. 

Altitude, velocity vector, and direction to all other aircraft 

and air traffic control facilities within a specific area. 

Automatic dependent surveillance-broadcast (ADS-B) 

information is displayed in the flight deck via a cockpit 

display of traffic information (CDTI) unit, providing the pilot 

with greater situational awareness. ADS-B transmissions 

also provide controllers with a more complete picture of 

traffic and update that information more frequently than 

other surveillance equipment.

Descend Via. A descend via clearance instructs you to follow 

the altitudes published on a STAR. You are not authorized to 

leave your last assigned altitude unless specifically cleared 

to do so. If ATC amends the altitude or route to one that 

is different from the published procedure, the rest of the 

charted descent procedure is canceled. ATC will assign 

you any further route, altitude, or airspeed clearances, as 

necessary.

Digital ATIS (D-ATIS). An alternative method of receiving 

ATIS reports by aircraft equipped with datalink services 

capable of receiving information in the flight deck over their 

Aircraft Communications Addressing and Reporting System 

(ACARS) unit.
G-4

Digital elevation model (DEM). A digital representation of 

ground surface topography or terrain.

Diverse Vector Area (DVA). An airport may establish a 

diverse vector area if it is necessary to vector aircraft below 

the minimum vectoring altitude to assist in the efficient 

flow of departing traffic. DVA design requirements are 

outlined in TERPS and allow for the vectoring of aircraft 

immediately off the departure end of the runway below 

the MVA.

Dynamic Magnetic Variation. A field that is simply a 

computer model calculated value instead of a measured 

value contained in the record for a waypoint. 

Electronic Flight Bag (EFB). An electronic display system 

intended primarily for flight deck or cabin use. EFB devices 

can display a variety of aviation data or perform basic 

calculations (e.g., performance data, fuel calculations, etc.). 

In the past, some of these functions were traditionally 

accomplished using paper references or were based on 

data provided to the flight crew by an airline’s flight dispatch 

function. The scope of the EFB system functionality may also 

include various other hosted databases and applications. 

Physical EFB displays may use various technologies, 

formats, and forms of communication. These devices are 

sometimes referred to as auxiliary performance computers 

(APC) or laptop auxiliary performance computers (LAPC). 

Ellipsoid of Revolution. The surface that results when an 

ellipse is rotated about one of its axes.

En Route Obstacle Clearance Areas. Obstacle clearance 

areas for en route planning are identified as primary, 

secondary, and turning areas, and they are designed to 

provide obstacle clearance route protection width for 

airways and routes.

Expanded Service Volume. When ATC or a procedures 

specialist requires the use of a NAVAID beyond the 

limitations specified for standard service volume, an 

expanded service volume (ESV) may be established. See 

standard service volume.

Feeder Route. A feeder route is a route depicted on IAP 

charts to designate courses for aircraft to proceed from the 

en route structure to the IAF. Feeder routes, also referred 

to as approach transitions, technically are not considered 

approach segments but are an integral part of many IAPs.

Field. See database field.

Final Approach and Takeoff Area (FATO). The FATO is a 

defined heliport area over which the final approach to a 

hover or a departure is made. The touchdown and lift-off 

area (TLOF) where the helicopter is permitted to land is 

normally centered in the FATO. A safety area is provided 

around the FATO. 

Fix. A geographical position determined by visual reference 

to the surface, by reference to one or more radio NAVAIDs, 

by celestial plotting, or by another navigational device. 

NOTE: Fix is a generic name for a geographical position 

and is referred to as a fix, waypoint, intersection, reporting 

point, etc.

Flight Information Region (FIR). A FIR is an airspace of 

defined dimensions within which Flight Information Service 

and Alerting Service are provided. Flight Information Service 

(FIS) is a service provided for the purpose of giving advice 

and information useful for the safe and efficient conduct 

of flights. Alerting Service is a service provided to notify 

appropriate organizations regarding aircraft in need of search 

and rescue aid, and assist such organizations as required. 

Flight Level (FL). A flight level is a level of constant 

atmospheric pressure related to a reference datum of 

29.92 "Hg. Each flight level is stated in three digits that 

represents hundreds of feet. For example, FL 250 represents 

an altimeter indication of 25,000 feet. 

Floating Waypoints. Floating waypoints represent 

airspace fixes at a point in space not directly associated 

with a conventional airway. In many cases, they may be 

established for such purposes as ATC metering fixes, 

holding points, RNAV-direct routing, gateway waypoints, 

STAR origination points leaving the en route structure, 

and SID terminating points joining the en route structure.

Fly-by (FB) Waypoint. A waypoint that requires the use of 

turn anticipation to avoid overshooting the next flight 

segment.

Fly-over (FO) Waypoint. A waypoint that precludes any turn 

until the waypoint is overflown, and is followed by either 

an intercept maneuver of the next flight segment or direct 

flight to the next waypoint.

Four Corner Post Configuration. An arrangement of air 

traffic pathways in a terminal area that brings incoming 

flights over fixes at four corners of the traffic area, while 

outbound flights depart between the fixes, thus minimizing 

conflicts between arriving and departing traffic.
G-5

Gateway Fix. A navigational aid or fix where an aircraft 

transitions between the domestic route structure and the 

oceanic route airspace.

Geodetic Datum. The reference plane from which geodetic 

calculations are made. Or, according to ICAO Annex 15, the 

numerical or geometrical quantity or set of such quantities 

(mathematical model) that serves as a reference for 

computing other quantities in a specific geographic region, 

such as the latitude and longitude of a point.

Glidepath Angle (GPA). The angular displacement of the 

vertical guidance path from a horizontal plane that passes 

through the reference datum point (RDP). This angle is 

published on approach charts (e.g., 3.00°, 3.20°, etc.). GPA 

is sometimes referred to as vertical path angle (VPA).

Global Navigation Satellite System (GNSS). An umbrella 

term adopted by the International Civil Aviation Organization 

(ICAO) to encompass any independent satellite navigation 

system used by a pilot to perform onboard position 

determinations from the satellite data.

Gross Navigation Error (GNE). In the North Atlantic area of 

operations, a gross navigation error is a lateral separation 

of more than 25 NM from the centerline of an aircraft’s 

cleared route, which generates an Oceanic Navigation Error 

Report. This report is also generated by a vertical separation 

if you are more than 300 feet off your assigned flight level.

Ground Communication Outlet (GCO). An unstaffed, 

remotely controlled ground/ground communications 

facility. Pilots at uncontrolled airports may contact ATC and 

AFSS via very high frequency (VHF) radio to a telephone 

connection. This lets pilots obtain an instrument clearance 

or close a VFR/IFR flight plan.

Head-Up Display (HUD). See head-up guidance system 

(HGS).

Head-up Guidance System (HGS). A system that projects 

critical flight data on a display positioned between the pilot 

and the windscreen. In addition to showing primary flight 

information, the HUD computes an extremely accurate 

instrument approach and landing guidance solution, and 

displays the result as a guidance cue for head-up viewing 

by the pilot.

Height Above Touchdown (HAT). The height of the DA 

above touchdown zone elevation (TDZE).

Highway in the Sky (HITS). A graphically intuitive pilot 

interface system that provides an aircraft operator with all 

of the attitude and guidance inputs required to safely fly 

an aircraft in close conformance to air traffic procedures.

Initial Climb Area (ICA). An area beginning at the departure 

end of runway (DER) to provide unrestricted climb to at 

least 400 feet above DER elevation.

Instrument Approach Waypoint. Fixes used in defining 

RNAV IAPs, including the feeder waypoint (FWP), the initial 

approach waypoint (IAWP), the intermediate waypoint 

(IWP), the final approach waypoint (FAWP), the RWY WP, 

and the APT WP, when required.

Instrument Landing System (ILS). A precision instrument 

approach system that normally consists of the following 

electronic components and visual aids: localizer, glide 

slope, outer marker, middle marker, and approach lights.

Instrument Procedure with Vertical Guidance (IPV). Satellite 

or flight management dystem (FMS) lateral navigation 

(LNAV) with computed positive vertical guidance based 

on barometric or satellite elevation. This term has been 

renamed APV.

International Civil Aviation Organization (ICAO).

ICAO is a specialized agency of the United Nations whose 

objective is to develop standard principles and techniques 

of international air navigation and to promote development 

of civil aviation.

Intersection. Typically, the point at which two VOR radial 

position lines cross on a route, usually intersecting at a good 

angle for positive indication of position, resulting in a VOR/

VOR fix.

Landing Distance Available (LDA). ICAO defines LDA as the 

length of runway, that is declared available and suitable for 

the ground run of an aeroplane landing.

Lateral Navigation (LNAV). Azimuth navigation without 

positive vertical guidance. This type of navigation is 

associated with nonprecision approach procedures or en 

route. 
G-6

Local Area Augmentation System (LAAS). LAAS further 

increases the accuracy of GPS and improves signal integrity 

warnings.

Localizer Performance with Vertical Guidance (LPV). LPV is 

one of the four lines of approach minimums found on an 

RNAV (GPS) approach chart. Lateral guidance accuracy is 

equivalent to a localizer. The HAT is published as a DA since 

it uses an electronic glide path that is not dependent on 

any ground equipment or barometric aiding and may be 

as low as 200 feet and 1⁄2 SM visibility depending on the 

airport terrain and infrastructure. WAAS avionics approved 

for LPV is required. Baro-VNAV is not authorized to fly the 

LPV line of minimums on a RNAV (GPS) procedure since it 

uses an internally generated descent path that is subject to 

cold temperature effects and incorrect altimeter settings.

Loss of Separation. An occurrence or operation that results 

in less than prescribed separation between aircraft, or 

between an aircraft and a vehicle, pedestrian, or object.

LPV. See Localizer Performance with Vertical Guidance. 

Magnetic Variation. The difference in degrees between 

the measured values of true north and magnetic north at 

that location.

Maximum Authorized Altitude (MAA). An MAA is a 

published altitude representing the maximum usable 

altitude or flight level for an airspace structure or route 

segment. It is the highest altitude on a Federal airway, jet 

route, RNAV low or high route, or other direct route for 

which an MEA is designated at which adequate reception 

of navigation signals is assured.

Metering Fix. A fix along an established route over which 

aircraft are metered prior to entering terminal airspace. 

Normally, this fix should be established at a distance from 

the airport which facilitates a profile descent 10,000 feet 

above airport elevation (AAE) or above.

Mid-RVR. The RVR readout values obtained from sensors 

located midfield of the runway.

Mileage Break. A point on a route where the leg segment 

mileage ends, and a new leg segment mileage begins, often 

at a route turning point.

Military Airspace Management System (MAMS). A 

Department of Defense system to collect and disseminate 

information on the current status of special use airspace. 

This information is provided to the Special Use Airspace 

Management System (SAMS). The electronic interface 

also provides SUA schedules and historical activation and 

utilization data.

Minimum Crossing Altitude (MCA). An MCA is the lowest 

altitude at certain fixes at which the aircraft must cross 

when proceeding in the direction of a higher minimum en 

route IFR altitude. MCAs are established in all cases where 

obstacles intervene to prevent pilots from maintaining 

obstacle clearance during a normal climb to a higher MEA 

after passing a point beyond which the higher MEA applies.

Minimum Descent Altitude (MDA). The lowest altitude, 

expressed in feet above mean sea level, to which descent 

is authorized on final approach or during circle-to-land 

maneuvering in execution of a standard instrument 

approach procedure where no electronic glide slope is 

provided.

Minimum En Route Altitude (MEA). The MEA is the lowest 

published altitude between radio fixes that assures 

acceptable navigational signal coverage and meets 

obstacle clearance requirements between those fixes. The 

MEA prescribed for a Federal Airway or segment, RNAV low 

or high route, or other direct route applies to the entire 

width of the airway, segment, or route between the radio 

fixes defining the airway, segment, or route.

Minimum IFR Altitude (MIA). Minimum altitudes for IFR 

operations are prescribed in 14 CFR Part 91. These MIAs are 

published on IFR charts and prescribed in 14 CFR Part 95 

for airways and routes, and in 14 CFR Part 97 for standard 

instrument approach procedures.

Minimum Navigation Performance Specifications (MNPS).

A set of standards that require aircraft to have a minimum 

navigation performance capability in order to operate in 

MNPS designated airspace. In addition, aircraft must be 

certified by their State of Registry for MNPS operation. 

Under certain conditions, non-MNPS aircraft can operate 

in MNPS airspace, however, standard oceanic separation 

minima is provided between the non-MNPS aircraft and 

other traffic.

Minimum Obstruction Clearance Altitude (MOCA). The 

MOCA is the lowest published altitude in effect between 

radio fixes on VOR airways, off-airway routes, or route 

segments that meets obstacle clearance requirements 

for the entire route segment. This altitude also assures 

acceptable navigational signal coverage only within 22 

NM of a VOR.

Minimum Reception Altitude (MRA). An MRA is determined 

by FAA flight inspection traversing an entire route of flight 
G-7

to establish the minimum altitude the navigation signal can 

be received for the route and for off-course NAVAID facilities 

that determine a fix. When the MRA at the fix is higher than 

the MEA, an MRA is established for the fix, and is the lowest 

altitude at which an intersection can be determined.

Minimum Safe Altitude (MSA). MSAs are published for 

emergency use on IAP charts. For conventional navigation 

systems, the MSA is normally based on the primary 

omnidirectional facility on which the IAP is predicated. 

For RNAV approaches, the MSA is based on the runway 

waypoint (RWY WP) for straight-in approaches, or the 

airport waypoint (APT WP) for circling approaches. For 

GPS approaches, the MSA center is the Missed Approach 

Waypoint (MAWP).

Minimum Vectoring Altitude (MVA). Minimum vectoring 

altitude charts are developed for areas where there are 

numerous minimum vectoring altitudes due to variable 

terrain features or man-made obstacles. MVAs are 

established for use by ATC when radar ATC is exercised.

Missed Approach Holding Waypoint (MAHWP). An 

approach waypoint sequenced during the holding portion 

of the missed approach procedure that is usually a fly-over 

waypoint, rather than a fly-by waypoint.

Missed Approach Waypoint (MAWP). An approach waypoint 

sequenced during the missed approach procedure that is 

usually a fly-over waypoint, rather than a fly-by waypoint.

National Airspace System (NAS). Consists of a complex 

collection of facilities, systems, equipment, procedures, and 

airports operated by thousands of people to provide a safe 

and efficient flying environment.

Navigational Gap. A navigational course guidance gap, 

referred to as an MEA gap, describes a distance along an 

airway or route segment where a gap in navigational signal 

coverage exists. The navigational gap may not exceed a 

specific distance that varies directly with altitude.

Next Generation Air Transportation System (NextGen).

Ongoing, wide-ranging transformation of the National 

Airspace System (NAS). NextGen represents an evolution 

from a ground-based system of air traffic control to a satellitebased system of air traffic management.

Non-Directional Radio Beacon (NDB). An L/MF or UHF 

radio beacon transmitting nondirectional signals whereby 

the pilot of an aircraft equipped with direction finding 

equipment can determine bearing to or from the radio 

beacon and “home” on or track to or from the station. When 

the radio beacon is installed in conjunction with the ILS 

marker, it is normally called a compass locator.

Non-RNAV DP. A DP whose ground track is based on 

ground-based NAVAIDS and/or dead reckoning navigation.

Obstacle Clearance Surface (OCS). An inclined or level 

surface associated with a defined area for obstruction 

evaluation.

Obstacle Departure Procedure (ODP). A procedure that 

provides obstacle clearance. ODPs do not include ATC 

related climb requirements. In fact, the primary emphasis 

of ODP design is to use the least erroneous route of flight to 

the en route structure while attempting to accommodate 

typical departure routes.

Obstacle Identification Surface (OIS). The design of a 

departure procedure is based on TERPS, a living document 

that is updated frequently. Departure design criteria 

assumes an initial climb of 200 feet per NM after crossing 

the departure end of the runway (DER) at a height of at 

least 35 feet above the ground. Assuming a 200 feet per 

NM climb, the departure is structured to provide at least 

48 feet per NM of clearance above objects that do not 

penetrate the obstacle slope. The slope, known as the 

obstacle identification slope (OIS), is based on a 40 to 1 

ratio, which is the equivalent of a 152-foot per NM slope.

Off-Airway Routes. The FAA prescribes altitudes governing 

the operation of aircraft under IFR for fairway routes in a 

similar manner to those on federal airways, jet routes, area 

navigation low or high altitude routes, and other direct 

routes for which an MEA is designated.

Off-Route Obstruction Clearance Altitude (OROCA). An offroute altitude that provides obstruction clearance with a 

1,000 foot buffer in nonmountainous terrain areas and a 

2,000 foot buffer in designated mountainous areas within 

the U.S. This altitude may not provide signal coverage from 

groundbased navigational aids, air traffic control radar, or 

communications coverage.

Operations Specifications (OpSpecs). A published 

document providing the conditions under which an air carrier 

and operator for compensation or hire must operate in order 

to retain approval from the FAA.

Pilot Briefing Information. The current format for charted 
G-8

IAPs issued by AJV-3. The information is presented in a 

logical order facilitating pilot briefing of the procedures. 

Charts include formatted information required for quick 

pilot or flight crew reference located at the top of the chart.

Point-in-Space (PinS) Approach. An approach normally 

developed to heliports that do not meet the IFR heliport 

design standards but meet the standards for a VFR 

heliport. A helicopter PinS approach can be developed 

using conventional NAVAIDs or RNAV systems. These 

procedures have either a VFR or visual segment between the 

MAP and the landing area. The procedure specifies a course 

and distance from the MAP to the heliport(s) and includes a 

note to proceed VFR or visually from the MAP to the heliport, 

or conduct the missed approach.

Positive Course Guidance (PCG). A continuous display of 

navigational data that enables an aircraft to be flown along 

a specific course line (e.g., radar vector, RNAV, groundbased NAVAID).

Precision Runway Monitor (PRM). Provides air traffic 

controllers with high precision secondary surveillance 

data for aircraft on final approach to parallel runways that 

have extended centerlines separated by less than 4,300 

feet. High resolution color monitoring displays (FMA) are 

required to present surveillance track data to controllers 

along with detailed maps depicting approaches and a no 

transgression zone.

Preferential Departure Route (PDR). A specific departure 

route from an airport or terminal area to an en route point 

where there is no further need for flow control. It may be 

included in an instrument Departure Procedure (DP) or a 

Preferred IFR Route.

Preferred IFR Routes. A system of preferred IFR routes 

guides you in planning your route of flight to minimize 

route changes during the operational phase of flight, and 

to aid in the efficient orderly management of air traffic 

using federal airways. 

Principal Operations Inspector (POI). Scheduled air 

carriers and operators for compensation or hire are assigned 

a principal operations inspector (POI) who works directly 

with the company and coordinates FAA operating approval.

Record. See Database Record.

Reduced Vertical Separation Minimums (RVSM). RVSM 

airspace is where air traffic control separates aircraft by 

a minimum of 1,000 feet vertically between flight level 

(FL) 290 and FL 410 inclusive. RVSM airspace is special 

qualification airspace; the operator and the aircraft used 

by the operator must be approved by the Administrator. 

Air traffic control notifies operators of RVSM by providing 

route planing information.

Reference Landing Speed (VREF). The speed of the airplane, 

in a specified landing configuration, at the point where it 

descends through the 50-foot height in the determination 

of the landing distance.

Remote Communications Outlet (RCO). An unmanned 

communications facility remotely controlled by air traffic 

personnel. RCOs serve FSSs and may be UHF or VHF. RCOs 

extend the communication range of the air traffic facility. 

RCOs were established to provide ground-to-ground 

communications between air traffic control specialists 

and pilots located at a satellite airport for delivering en 

route clearances, issuing departure authorizations, and 

acknowledging IFR cancellations or departure/landing 

times.

Reporting Point. A geographical location in relation 

to which the position of an aircraft is reported. (See 

Compulsory Reporting Points).

Required Navigation Performance (RNP). RNP is a statement 

of the navigation performance necessary for operation 

within a defined airspace. On-board monitoring and 

alerting is required.

RNAV DP. A Departure Procedure developed for RNAVequipped aircraft whose ground track is based on satellite 

or DME/DME navigation systems.

Roll-Out RVR. The RVR readout values obtained from 

sensors located nearest the rollout end of the runway.

Runway Heading. The magnetic direction that corresponds 

with the runway centerline extended, not the painted 

runway numbers on the runway. Pilots cleared to “fly or 

maintain runway heading” are expected to fly or maintain 

the published heading that corresponds with the extended 

centerline of the departure runway (until otherwise 

instructed by ATC), and are not to apply drift correction 

(e.g., RWY 4, actual magnetic heading of the runway 

centerline 044.22°, fly 044°).

Runway Hotspots. Locations on a particular airport that 

historically have hazardous intersections. Hot spots alert 

pilots to the fact that there may be a lack of visibility at 

certain points or the tower may be unable to see that 

particular intersection. Whatever the reason, pilots need 
G-9

to be aware that these hazardous intersections exist and 

they should be increasingly vigilant when approaching 

and taxiing through these intersections. Pilots are typically 

notified of these areas by a Letter to Airmen or by accessing 

the FAA Office of Runway Safety.

Runway Incursion. An occurrence at an airport involving 

an aircraft, vehicle, person, or object on the ground that 

creates a collision hazard or results in a loss of separation 

with an aircraft that is taking off, intending to take off, 

landing, or intending to land.

Runway Safety Program (RSP). Designed to create and 

execute a plan of action that reduces the number of runway 

incursions at the nation’s airports.

Runway Visual Range (RVR). An estimate of the maximum 

distance at which the runway, or the specified lights or 

markers delineating it, can be seen from a position above 

a specific point on the runway centerline. RVR is normally 

determined by visibility sensors or transmissometers 

located alongside and higher than the centerline of the 

runway. RVR is reported in hundreds of feet.

Runway Visibility Value (RVV). The visibility determined 

for a particular runway by a transmissometer. A meter 

provides a continuous indication of the visibility (reported 

in miles or fractions of miles) for the runway. RVV is used 

in lieu of prevailing visibility in determining minimums for 

a particular runway.

Significant Point. [ICAO Annex 11] A specified geographical 

location used in defining an ATS route or the flightpath 

of an aircraft and for other navigation and ATS purposes.

Special Instrument Approach Procedure. A procedure 

approved by the FAA for individual operators, but not 

published in FAR 97 for public use.

Special Use Airspace Management System (SAMS). A 

joint FAA and military program designed to improve civilian 

access to special use airspace by providing information on 

whether the airspace is active or scheduled to be active. The 

information is available to authorized users via an Internet 

website.

Standard Instrument Departure (SID). An ATC requested 

and developed departure route designed to increase capacity 

of terminal airspace, effectively control the flow of traffic 

with minimal communication, and reduce environmental 

impact through noise abatement procedures.

Standard Service Volume. Most air navigation radio aids 

that provide positive course guidance have a designated 

standard service volume (SSV). The SSV defines the 

reception limits of unrestricted NAVAIDS that are usable for 

random/unpublished route navigation. Standard service 

volume limitations do not apply to published IFR routes or 

procedures. See the AIM (Chapter 1) for the SSV for specific 

NAVAID types.

Standard Terminal Arrival (STAR). Provides a common 

method for departing the en route structure and navigating 

to your destination. A STAR is a preplanned instrument 

flight rule ATC arrival procedure published for pilot use 

in graphic and textual form to simplify clearance delivery 

procedures. STARs provide you with a transition from the 

en route structure to an outer fix or an instrument approach 

fix or arrival waypoint in the terminal area, and they usually 

terminate with an instrument or visual approach procedure.

Standardized Taxi Routes. Coded taxi routes that follow 

typical taxiway traffic patterns to move aircraft between 

gates and runways. ATC issues clearances using these 

coded routes to reduce radio communication and eliminate 

taxi instruction misinterpretation.

STAR Transition. A published segment used to connect 

one or more en route airways, jet routes, or RNAV routes 

to the basic STAR procedure. It is one of several routes that 

bring traffic from different directions into one STAR. STARs 

are published for airports with procedures authorized by 

the FAA, and these STARs are included at the front of each 

Terminal Procedures Publication regional booklet.

Start End of Runway (SER). The beginning of the takeoff 

runway available.

Station Declination. The angular difference between true 

north and the zero radial of a VOR at the time the VOR was 

last site-checked.

Surface Incident. An event during which authorized or 

unauthorized/unapproved movement occurs in the 

movement area or an occurrence in the movement area 

associated with the operation of an aircraft that affects or 

could affect the safety of flight.

Surface Movement Guidance Control System (SMGCS).

Facilitates the safe movement of aircraft and vehicles 

at airports where scheduled air carriers are conducting 

authorized operations. The SMGCS low visibility taxi plan 

includes the improvement of taxiway and runway signs, 

markings, and lighting, as well as the creation of SMGCS 

low visibility taxi route charts.

Synthetic Vision System (SVS). A visual display of terrain, 
G-10

obstructions, runways, and other surface features that creates 

a virtual view of what the pilot would see out the window. 

This tool could be used to supplement normal vision in 

low visibility conditions, as well as to increase situational 

awareness in IMC.

System Wide Information Management (SWIM).

An advanced technology program designed to facilitate 

greater sharing of Air Traffic Management (ATM) system 

information, such as airport operational status, weather 

information, flight data, status of special use airspace, 

and National Airspace System (NAS) restrictions. SWIM 

supports current and future NAS programs by providing 

flexible and secure information management architecture for 

sharing NAS information.

Takeoff Distance Available (TODA). ICAO defines TODA as 

the length of the takeoff runway available plus the length 

of the clearway, if provided. 

Takeoff Runway Available (TORA). ICAO defines TORA as 

the length of runway declared available and suitable for 

the ground run of an aeroplane takeoff.

Tangent Point (TP). The point on the VOR/DME RNAV route 

centerline from which a line perpendicular to the route 

centerline would pass through the reference facility.

Terminal Arrival Area (TAA). TAAs are the method by which 

aircraft are transitioned from the RNAV en route structure 

to the terminal area with minimal ATC interaction. The TAA 

consists of a designated volume of airspace designed to 

allow aircraft to enter a protected area, offering guaranteed 

obstacle clearance where the initial approach course is 

intercepted based on the location of the aircraft relative 

to the airport.

Threshold. The beginning of the part of the runway usable 

for landing.

Top Of Climb (TOC). An identifiable waypoint representing 

the point at which cruise altitude is first reached. TOC is 

calculated based on your current aircraft altitude, climb 

speed, and cruise altitude. There can only be one TOC 

waypoint at a time.

Top Of Descent (TOD). Generally utilized in flight 

management systems, top of descent is an identifiable 

waypoint representing the point at which descent is first 

initiated from cruise altitude. TOD is generally calculated 

using the destination elevation (if available) and the 

descent speed schedule.

Touchdown and Lift-Off Area (TLOF). The TLOF is a load 

bearing, usually paved, area at a heliport where the 

helicopter is permitted to land. The TLOF can be located 

at ground or rooftop level, or on an elevated structure. The 

TLOF is normally centered in the FATO.

Touchdown RVR. The RVR visibility readout values 

obtained from sensors serving the runway touchdown zone.

Touchdown Zone Elevation (TDZE). The highest elevation 

in the first 3,000 feet of the landing surface.

Tower En Route Control (TEC). The control of IFR en route 

traffic within delegated airspace between two or more 

adjacent approach control facilities. This service is designed 

to expedite air traffic and reduces air traffic control and 

pilot communication requirements.

TRACAB. A new type of air traffic facility that consists of 

a radar approach control facility located in the tower cab of 

the primary airport, as opposed to a separate room.

Traffic Information Service-Broadcast (TIS-B). An air 

traffic surveillance system that combines all available traffic 

information on a single display.

Traffic Management Advisor (TMA). A software suite that 

helps air traffic controllers to sequence arriving air traffic.

Transition Altitude (QNH). The altitude in the vicinity of an 

airport at or below which the vertical position of an aircraft 

is controlled by reference to altitudes (MSL).

Transition Height (QFE). Transition height is the height in 

the vicinity of an airport at or below which the vertical 

position of an aircraft is expressed in height above the 

airport reference datum.

Transition Layer. Transition layer is the airspace between 

the transition altitude and the transition level. Aircraft 

descending through the transition layer will set altimeters 

to local station pressure, while departing aircraft climbing 

through the transition layer will be using standard altimeter 

setting (QNE) of 29.92 inches of Mercury, 1013.2 millibars, 

or 1013.2 hectopascals.

Transition Level (QNE). The lowest flight level available for 

use above the transition altitude. 

Turn Anticipation. The capability of RNAV systems to 

determine the point along a course, prior to a turn WP, 

where a turn should be initiated to provide a smooth path 

to intercept the succeeding course and to enunciate the 

information to the pilot.
G-11

Turn WP (Turning Point). A WP that identifies a change from 

one course to another.

Universal Communications (UNICOM). An air-ground 

communication facility operated by a private agency to 

provide advisory service at uncontrolled aerodromes and 

airports.

User-Defined Waypoint. User-defined waypoints typically 

are created by pilots for use in their own random RNAV 

direct navigation. They are newly established, unpublished 

airspace fixes that are designated geographic locations/

positions that help provide positive course guidance for 

navigation and a means of checking progress on a flight. 

They may or may not be actually plotted by the pilot on 

en route charts, but would normally be communicated to 

ATC in terms of bearing and distance or latitude/longitude. 

An example of user-defined waypoints typically includes 

those derived from database-driven area navigation (RNAV) 

systems whereby latitude/longitude coordinate-based 

waypoints are generated by various means including 

keyboard input, and even electronic map mode functions 

used to establish waypoints with a cursor on the display. 

Another example is an offset phantom waypoint, which 

is a point in space formed by a bearing and distance from 

NAVAIDs, such as VORs, VORTACs, and TACANs, using a 

variety of navigation systems.

User Request Evaluation Tool (URET). The URET helps 

provide enhanced, automated flight data management. 

URET is an automated tool provided at each radar position 

in selected en route facilities. It uses flight and radar data 

to determine present and future trajectories for all active 

and proposed aircraft flights. A graphic plan display 

depicts aircraft, traffic, and notification of predicted 

conflicts. Graphic routes for current plans and trial plans 

are displayed upon controller request. URET can generate 

a predicted conflict of two aircraft, or between aircraft 

and airspace. 

Vertical Navigation (VNAV). Traditionally, the only way 

to get glidepath information during an approach was to 

use a ground-based NAVAID, but modern area navigation 

systems allow flight crews to display an internally 

generated descent path that allows a constant rate descent 

to minimums during approaches that would otherwise 

include multiple level-offs.

Vertical Navigation Planning. Included within certain STARs 

is information provided to help you reduce the amount of 

low altitude flying time for high performance aircraft, like 

jets and turboprops. An expected altitude is given for a key 

fix along the route. By knowing an intermediate altitude in 

advance when flying a high performance aircraft, you can 

plan the power or thrust settings and aircraft configurations 

that result in the most efficient descent, in terms of time, 

fuel requirements, and engine wear.

Visual Approach. A visual approach is an ATC authorization 

for an aircraft on an IFR flight plan to proceed visually to 

the airport of intended landing; it is not an IAP. Also, there 

is no missed approach segment. When it is operationally 

beneficial, ATC may authorize pilots to conduct a visual 

approach to the airport in lieu of the published IAP. A visual 

approach can be initiated by a pilot or the controller.

Visual Climb Over the Airport (VCOA). An option to allow 

an aircraft to climb over the airport with visual reference 

to obstacles to attain a suitable altitude from which to 

proceed with an IFR departure.

Waypoints. Area navigation waypoints are specified 

geographical locations, or fixes, used to define an area 

navigation route or the flightpath of an aircraft employing 

area navigation. Waypoints may be any of the following 

types: predefined, published, floating, user-defined, fly-by, 

or fly-over.

Waypoint (WP). A predetermined geographical position used 

for route/instrument approach definition, progress reports, 

published VFR routes, visual reporting points or points for 

transitioning and/or circumnavigating controlled and/or 

special use airspace, that is defined relative to a VORTAC 

station or in terms of latitude/longitude coordinates.

Wide Area Augmentation System (WAAS). A method of 

navigation based on GPS. Ground correction stations transmit 

position corrections that enhance system accuracy and add 

vertical navigation (VNAV) features.
G-12
I-1

Index

Approaches...............................................................................4-56

Approach planning...................................................................4-2

Approach to a PinS .................................................................7-14

Approach to a specific VFR heliport .................................7-14

Area navigation (RNAV) systems..........................................6-1

Global positioning system (GPS).....................................6-2

Multisensory flight management system (FMS)........6-2

ARTCC Radio Frequency Outage .......................................2-48

ATC holding instructions......................................................2-51

ATC requirements during an inflight emergency..........A-4

Emergency airport................................................................A-5

Emergency Obstruction Video Map (EOVM)...............A-6

Escort.........................................................................................A-6

Provide information.............................................................A-5

Radar assistance ....................................................................A-5

Responsibility.........................................................................A-6

Automated Terminal Information Sevice (ATIS) .............4-5

Automated weather observing programs.......................4-5

Automated Surface Observing System (ASOS)/

Automated Weather Sensor System (AWSS)...............4-5

Automated Weather Observing System (AWOS).......4-5

Automated weather systems..............................................1-11

ASOS/Automated Weather Sensor System 

(AWSS).....................................................................................1-11

Automated Weather Observing System (AWOS).....1-11

Automated Weather Sensor System (AWSS).............1-11

Automatic Terminal Information Service (ATIS)............1-12

Autopilot modes......................................................................4-35

Aviation Digital Data Services (ADDS)...............................4-4

B

Benefits of NextGen..................................................................5-6

Broadcast Weather....................................................................4-5

C

CAT II and III approaches.......................................................4-71

Ceilings........................................................................................1-11

Center Weather Advisories (CWA) .......................................4-6

Changeover points.................................................................2-20

Charted Visual Flight Procedures (CVFP) ........................4-59

A

Access to special use airspace ............................................5-10

Advanced Surface Movement Guidance Control 

System (A-SMGCS) ....................................................................1-4

Airport signs, lighting, and markings............................1-4

Aeronautical Radio, Inc. (ARINC)..........................................6-4

Aeronautical Radio, Inc. (ARINC) 424..................................6-4

Complex route records.......................................................6-5

Fix records................................................................................6-4

Miscellaneous records.........................................................6-5

Simple route records............................................................6-4

Victor airway.......................................................................6-5

Airborne navigation database standardization .............6-3

Aircraft approach categories.................................................4-8

Aircraft performance considerations.................................4-7

Aircraft speed and altitude ..................................................2-49

Aircraft system malfunctions................................................A-2

Airplane performance operating limitations..................4-7

Airport Facility Directory (A/FD)...........................................1-2

Airport/runway information................................................4-33

Airport sketches and diagrams............................................1-2

Airport Surveillance Radar (ASR) .......................................4-87

Airports with an ATC tower..................................................4-15

Airports without a control tower.......................................4-15

Air Route Traffic Control Center (ARTCC) ............... 2-3, 4-13

High or Lack of Minimum Vectoring Altitudes 

(MVAs) .....................................................................................4-14

Lack of approach control terrain advisories..............4-15

Airspeed......................................................................................3-20

Airway and route system......................................................2-13

Airway/route depiction.........................................................2-13

IFR en route high altitude chart.....................................2-17

IFR en route low altitude chart.......................................2-14

Victor airway navigation procedures...........................2-18

Airways..........................................................................................2-2

Alternate minimums for commercial operators...........1-14

Altitude .......................................................................................3-16

Altitudes.....................................................................................4-19

Approach chart naming conventions................................4-9

Approach clearance.....................................................3-22, 4-54

Approach control ....................................................................4-13
I-2

Charting/database inconsistencies..................................6-15

Issues related to magnetic variation............................6-16

Issues related to revision cycle.......................................6-17

Naming conventions.........................................................6-15

Circling only procedures.......................................................4-11

Civilians using special use airspace ..................................5-11

Climbing and descending en route..................................2-48

Closed indefinitely airports.................................................6-15

Communication failure .........................................................2-47

Communications.....................................................................4-11

Computer navigation performance..................................2-33

Contact approaches...............................................................4-59

Controlled Flight Into Terrain (CFIT) ...................................3-9

Converging ILS approaches.................................................4-80

Copter GPS approaches to an airport or heliport........7-10

Copter only approaches to an airport or heliport.......7-10

Course reversal.........................................................................4-50

Courses........................................................................................4-17

Area navigation courses...................................................4-18

Traditional courses.............................................................4-17

Cruise clearance.......................................................................2-43

Cyclic redundancy check (CRC)..........................................6-13

D

Decision altitude (DA)............................................................4-20

Decision height (DH)..............................................................4-20

Departure procedures (DP)..................................................1-14

Obstacle departure procedures (ODPs)......................1-23

Area Navigation (RNAV) departures........................1-30

ODP flight planning considerations........................1-23

Pilot responsibility for use of RNAV 

departures.........................................................................1-36

SID altitudes......................................................................1-36

SID flight planning considerations...........................1-26

Standard instrument departures (SIDs)..................1-23

Transition routes.............................................................1-26

Departures from airports without an operating 

control tower ............................................................................1-43

Departures from tower-controlled airports...................1-43

Descending from the en route altitude.............................3-8

Descent planning......................................................................3-3

Descent planning for high performance aircraft...........3-6

Descent rates and glidepaths for nonprecision 

approaches................................................................................4-37

Maximum acceptable descent rates............................4-37

Descents.....................................................................................4-36

Design criteria...........................................................................1-16

Digital Automatic Terminal Information Service 

(D-ATIS)........................................................................................1-12

Direct route flights..................................................................2-21

Direct User Access Terminal System (DUATS)..................4-4

Diverse vector area .................................................................1-38

Diversion procedures.............................................................2-52

DME arcs.....................................................................................4-50

DP responsibilities...................................................................1-42

E

Electronic flight bag (EFB)......................................................5-9

Emergency procedures...........................................................A-1

Enhanced Flight Vision Systems (EFVS)...........................4-20

En route holding procedures..............................................2-51

En route navigation..................................................................2-2

En route obstacle clearance areas.....................................2-18

Primary and secondary en route obstacle 

clearance areas....................................................................2-19

En route reporting procedures...........................................2-46

En route safety considerations...........................................2-52

Equipment requirements.....................................................4-17

Example approach briefing .................................................4-46

F

Feeder routes............................................................................4-49

Final approach fix (FAF) altitude ........................................4-19

Final approach segment.......................................................4-53

Flight and navigation equipment.......................................7-2

Flight Information Service—Broadcast (FIS-B)...............4-4

Flight level (FL).........................................................................2-43

Flight Management System (FMS)....................................4-33

Flights in a radar environment...........................................2-46

Fuel state awareness..............................................................2-52

G

Generator failure........................................................................A-2

Global Navigation Satellite System (GNSS)......................2-2

GPS overlay of nonprecision approach...........................4-62

GPS stand-alone/RNAV (GPS) approach..........................4-62

Ground-Based Augmentation System (GBAS)..............4-26

Ground communication outlet..........................................1-43

H

Hazardous Inflight Weather Advisory Service 

(HIWAS) .........................................................................................4-4

Head-Up Displays (HUD).........................................................5-7

Helicopter approaches to VFR heliports.........................7-14

Helicopter flight manual (HFM)............................................7-3

Helicopter flight manual limitations..................................7-3

Helicopter IFR alternates........................................................7-8

Part 91 operators...................................................................7-8

Part 135 operators................................................................7-9

Helicopter IFR Takeoff Minimums........................................7-8

Helicopter instrument approaches.....................................7-9
I-3

Standard instrument approach procedures to an 

airport .......................................................................................7-9

Helicopter Instrument Flight Rule (IFR) 

certification..................................................................................7-2

Helicopters flying standard instrument approach 

procedures (SIAP)......................................................................7-9

Helicopter VFR minimums.....................................................7-8

High altitude area navigation routing...............................2-7

High performance holding..................................................2-52

Holding patterns......................................................................3-21

I

IFR alternate requirements..................................................1-12

IFR cruising altitude or flight level.....................................2-42

IFR en route altitudes.............................................................2-35

IFR heliports..............................................................................7-17

ILS approaches.........................................................................4-68

ILS approach categories...................................................4-69

ILS approaches to parallel runways..............................4-64

Parallel (dependent) ILS approaches...........................4-71

Simultaneous close parallel ILS precision 

runway monitor (PRM) approaches..............................4-75

Simultaneous parallel ILS approaches........................4-71

Inadvertent icing encounter.................................................A-2

Precipitation static................................................................A-2

Inadvertent IMC.......................................................................7-16

Inadvertent Instrument Meteorological Condition 

(IIMC)..............................................................................................A-4

Inadvertent thunderstorm encounter...............................A-1

Initial approach segment .....................................................4-53

Instrument approach charts..................................................4-9

Instrument approaches.........................................................4-20

Instrument approach procedure (IAP) briefing............4-33

Instrument approach procedure segments..................4-49

Instrument failure......................................................................A-3

Intermediate approach segment.......................................4-53

Interpreting the STAR.............................................................3-12

L

Lateral navigation/vertical navigation 

(LNAV/VNAV) equipment.......................................................3-6

LF/MF airways...........................................................................2-18

Localizer approaches.............................................................4-87

Localizer back course.............................................................4-87

Localizer DME ...........................................................................4-87

Localizer-Type Directional Aid (LDA)...............................4-87

Locator outer markers (LOMs) ............................................6-16

Loss of situational awareness (SA) ......................................A-3

Low, close-in obstacles..........................................................1-18

Lowest usable flight level.....................................................2-43

M

Maintaining aircraft control...................................................A-4

Assistance ................................................................................A-4

Maximum authorized altitude (MAA) ..............................2-36

Maximum holding speed.....................................................2-52

Minimum crossing altitude (MCA)....................................2-40

Minimum descent altitude (MDA).....................................4-20

Minimum en route altitude (MEA) ....................................2-35

Minimum Equipment List (MEL) ..........................................7-5

Minimum IFR altitude (MIA) ................................................2-40

Minimum obstruction clearance altitude (MOCA)......2-36

Minimum reception altitude (MRA)..................................2-35

Minimum safe altitudes (MSAs) .........................................4-19

Minimum turning altitude (MTA).......................................2-38

Minimum vectoring altitudes (MVA)................................2-41

Missed approach .....................................................................4-39

Missed approach segment...................................................4-54

Monitoring of navigation facilities....................................2-29

N

National Aeronautical Navigation Products 

(AeroNav Products)...........................................................1-2, 2-6

NAVAID accuracy check ........................................................2-29

Airborne VOR check ...........................................................2-31

Dual VOR check....................................................................2-31

NDB accuracy check...........................................................2-31

RNAV accuracy check.........................................................2-32

VOR accuracy........................................................................2-29

VOR checkpoint signs........................................................2-29

VOT...........................................................................................2-30

Navigational gaps...................................................................2-29

Navigation and communication radios...........................4-33

Navigation in the arrival environment ..............................3-2

NDB approach ..........................................................................4-84

Next Generation Air Transportation System 

(NextGen).....................................................................................5-2

Automatic dependent surveillance-broadcast 

(ADS-B)......................................................................................5-2

NAS voice switch (NVS).......................................................5-3

Next generation data communications........................5-3

Next generation network enabled weather 

(NNEW) .....................................................................................5-3

System wide information management (SWIM) .......5-2

NextGen existing improvements.........................................5-3

Noise abatement procedures.............................................1-42

Non-directional beacons (NDBs) .......................................6-16

Nonradar environment .........................................................4-56

Non-radar position reports..................................................2-46
I-4

O

Off-airway routes.....................................................................2-26

Off-route obstruction clearance altitude ...................2-27

One-engine-inoperative (OEI) takeoff obstacle 

clearance requirements........................................................1-19

Operational limitations of airborne navigation 

databases...................................................................................6-14

Operations in other countries.............................................2-44

Operations specifications (OpsSpecs)................................1-8

P

Path and terminator legs........................................................6-5

Path and terminator limitations.......................................6-9

Pilot in command (PIC)............................................................A-1

Pilot proficiency .........................................................................7-5

Pitot/static system failure.......................................................A-3

Position report items..............................................................2-46

Additional reports...............................................................2-47

Precision Approach Radar (PAR) ........................................4-84

Preferred IFR routes..................................................................2-7

Preparing for the arrival ........................................................3-16

Present position direct..........................................................3-24

Primary NAVAID.......................................................................4-17

Procedural notes......................................................................1-42

Published RNAV routes..........................................................2-23

Composition of designators............................................2-23

Use of designators in communications......................2-24

R

Radar approaches...................................................................4-84

Radar departures.....................................................................1-37

Radar vectors to final approach course...........................3-24

Random RNAV routes.............................................................2-25

Reduced Vertical Separation Minimums (RSVM) .........2-43

Required navigation performance (RNP)........................2-34

RNP levels...............................................................................2-35

Application of standard RNP levels..........................2-35

Standard RNP levels.......................................................2-35

Required navigation performance (RNP)........................4-26

Reviewing the approach.......................................................3-16

RNAV approach authorization............................................4-30

Baro-VNAV .............................................................................4-30

Hot and cold temperature limitations....................4-31

RNAV approaches....................................................................4-59

RNAV approach types............................................................4-62

RNAV (GPS) approach using WAAS ...................................4-65

RNAV minimum en route altitude.....................................2-35

RNAV STAR transitions...........................................................3-12

Role of the avionics manufacturer....................................6-13

Role of the database provider ............................................6-13

Runway hotspots.......................................................................1-6

Runway incursions....................................................................1-5

S

Safe separation standards......................................................2-4

Inflight requirements and instructions.........................2-6

Sectors......................................................................................2-5

See and avoid techniques....................................................1-44

Simplified Directional Facility (SDF)..................................4-88

Simultaneous offset instrument approaches 

(SOIAs).........................................................................................4-79

Stabilization and Automatic Flight Control

System (AFCS).............................................................................7-2

Aerodynamic surfaces.........................................................7-2

Attitude Retention Systems (ATT)...................................7-3

Autopilot systems (APs)......................................................7-3

Flight directors (FDs)............................................................7-3

Stability Augmentation Systems (SAS)..........................7-2

Trim systems...........................................................................7-2

Stabilized approach................................................................4-36

Standardized taxi routes.........................................................1-6

Taxi and movement operations change.......................1-6

Standard Terminal Arrival Routes (STARs) ......................3-10

STAR procedures......................................................................3-16

STAR transitions.......................................................................3-12

Storage limitations..................................................................6-15

Straight-in procedures.............................................................4-9

Substitute airway or route structures................................2-9

Substitute airway en route flight procedures.............2-9

Surface Movement Guidance Control System 

(SMGCS)........................................................................................1-3

Clearance bar lights..............................................................1-3

Geographic position markings........................................1-3

Runway guard lights............................................................1-3

Stop bars lights......................................................................1-3

Taxiway centerline lead-on light.....................................1-3

Surface movement safety ......................................................1-2

Synthetic and enhanced vision systems...........................5-8

Developing combined technology ................................5-9

Enhanced Flight Vision System (EFVS)...........................5-8

Synthetic Vision System (SVS)...........................................5-7

T

Takeoff minimums....................................................................1-8

Takeoff minimums for commercial operators.................1-8

Telephone Information Briefing Service (TIBS)...............4-4

Terminal arrival area (TAA)...................................................4-59

Terminal instrument procedures (TERPS).......................1-16

Terminal Routes.......................................................................4-50

Tower en route control (TEC) ..............................................2-10
I-5

Tower en route control route descriptions................2-10

Transition to a visual approach ..........................................4-39 U

Users role....................................................................................6-14 V

Vectors to final approach course.......................................4-54

Vertical navigation..................................................................4-23

Vertical navigation (VNAV) planning .................................3-4

VHF airways...............................................................................2-18

Visibility.......................................................................................1-10

Adequate visual reference...............................................1-11

Prevailing visibility..............................................................1-10

Runway visibility value (RVV)..........................................1-10

Runway visual range (RVR) ..............................................1-10

Mid-RVR..............................................................................1-11

Rollout RVR .......................................................................1-11

Touchdown RVR..............................................................1-11

Tower visibility .....................................................................1-10

Visual approaches...................................................................4-56

Visual climb over airport (VCOA) .......................................1-42

Visual flight rules (VFR) departures...................................1-44

VOR approach...........................................................................4-80 W

Waypoints..................................................................................2-32

Floating waypoints.............................................................2-32

User-defined waypoints...................................................2-32

Weather and the departure environment........................1-8

Weather considerations..........................................................4-2

Weather regulatory requirements.......................................4-6

Part 91 operators...................................................................4-6

Part 121 operators................................................................4-7

Part 135 operators................................................................4-7

Weather sources........................................................................4-2

Wide Area Augmentation System (WAAS)............ 3-6, 4-23

Advantages of WAAS enabled LPV 

Approaches...........................................................................4-23

Benefits of WAAS in the airport environment...........4-23
I-6