F FAA-G-8082-22

U.S. Department 

of Transportation

Federal Aviation

Administration

Remote Pilot – Small 

Unmanned Aircraft Systems

Study Guide

August 2016

Flight Standards Service

Washington, DC 20591
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Remote Pilot – Small Unmanned Aircraft Systems Study Guide i

Preface

The Federal Aviation Administration (FAA) has published the Remote Pilot – Small Unmanned Aircraft 

Systems (sUAS) Study Guide to communicate the knowledge areas you need to study to prepare to 

take the Remote Pilot Certificate with an sUAS rating airman knowledge test.

This Remote Pilot – Small Unmanned Aircraft Systems Study Guide is available for download from 

faa.gov. Please send comments regarding this document to afs630comments@faa.gov.
Remote Pilot – Small Unmanned Aircraft Systems Study Guide ii

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Remote Pilot – Small Unmanned Aircraft Systems Study Guide iii

Table of Contents

Introduction........................................................................................................................... 1

Obtaining Assistance from the Federal Aviation Administration (FAA).............................................. 1

FAA Reference Material ...................................................................................................................... 1

Chapter 1: Applicable Regulations.......................................................................................... 3

Chapter 2: Airspace Classification, Operating Requirements, and Flight Restrictions .............. 5

Introduction......................................................................................................................................... 5

Controlled Airspace ............................................................................................................................. 5

Uncontrolled Airspace......................................................................................................................... 6

Special Use Airspace............................................................................................................................ 6

Other Airspace Areas........................................................................................................................... 9

Air Traffic Control and the National Airspace System....................................................................... 12

Visual Flight Rules (VFR) Terms & Symbols....................................................................................... 12

Notices to Airmen (NOTAMs)............................................................................................................ 13

Chapter 3a: Aviation Weather Sources................................................................................. 15

Introduction....................................................................................................................................... 15

Surface Aviation Weather Observations........................................................................................... 15

Aviation Weather Reports................................................................................................................. 15

Aviation Forecasts ............................................................................................................................. 18

Convective Significant Meteorological Information (WST)............................................................... 19

Chapter 3b: Effects of Weather on Small Unmanned Aircraft Performance .......................... 21

Introduction....................................................................................................................................... 21

Density Altitude................................................................................................................................. 21

Performance...................................................................................................................................... 22

Measurement of Atmosphere Pressure............................................................................................ 22

Effect of Obstructions on Wind......................................................................................................... 23

Low-Level Wind Shear....................................................................................................................... 23

Atmospheric Stability ........................................................................................................................ 24

Temperature/Dew Point Relationship .............................................................................................. 25

Clouds................................................................................................................................................ 25

Fronts................................................................................................................................................. 26

Mountain Flying................................................................................................................................. 26

Structural Icing................................................................................................................................... 26

Thunderstorm Life Cycle.................................................................................................................... 26

Ceiling ................................................................................................................................................ 28

Visibility ............................................................................................................................................. 28

Chapter 4: Small Unmanned Aircraft Loading ....................................................................... 29
Remote Pilot – Small Unmanned Aircraft Systems Study Guide iv

Introduction....................................................................................................................................... 29

Weight ............................................................................................................................................... 29

Stability.............................................................................................................................................. 30

Load Factors....................................................................................................................................... 30

Weight and Balance........................................................................................................................... 32

Chapter 5: Emergency Procedures........................................................................................ 35

Introduction....................................................................................................................................... 35

Inflight Emergency............................................................................................................................. 35

Chapter 6: Crew Resource Management .............................................................................. 37

Chapter 7: Radio Communication Procedures ...................................................................... 39

Introduction....................................................................................................................................... 39

Understanding Proper Radio Procedures.......................................................................................... 39

Traffic Advisory Practices at Airports without Operating Control Towers ....................................... 39

Chapter 8: Determining the Performance of Small Unmanned Aircraft................................. 43

Introduction....................................................................................................................................... 43

Effect of Temperature on Density..................................................................................................... 43

Effect of Humidity (Moisture) on Density ......................................................................................... 43

Chapter 9: Physiological Factors (Including Drugs and Alcohol) Affecting Pilot 

Performance...................................................................................................... 45

Introduction....................................................................................................................................... 45

Physiological/Medical Factors that Affect Pilot Performance .......................................................... 45

Vision and Flight ................................................................................................................................ 50

Chapter 10: Aeronautical Decision-Making and Judgment.................................................... 51

Introduction....................................................................................................................................... 51

History of ADM .................................................................................................................................. 51

Risk Management.............................................................................................................................. 52

Crew Resource Management (CRM) and Single-Pilot Resource Management................................ 53

Hazard and Risk ................................................................................................................................. 53

Human Factors................................................................................................................................... 56

The Decision-Making Process............................................................................................................ 57

Decision-Making in a Dynamic Environment .................................................................................... 59

Situational Awareness....................................................................................................................... 63

Chapter 11: Airport Operations............................................................................................ 65

Introduction....................................................................................................................................... 65

Types of Airports ............................................................................................................................... 65

Sources for Airport Data.................................................................................................................... 65

Latitude and Longitude (Meridians and Parallels) ............................................................................ 68
Remote Pilot – Small Unmanned Aircraft Systems Study Guide v

Antenna Towers ................................................................................................................................ 69

Chapter 12: Maintenance and Preflight Inspection Procedures ............................................ 71

Appendix 1: Study References.............................................................................................. 74

Appendix 2: Registration and Marking Requirements for Small Unmanned Aircraft ............. 76

Appendix 3: Abbreviations and Acronyms............................................................................ 78
Remote Pilot – Small Unmanned Aircraft Systems Study Guide vi

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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 1 

Introduction

The information in this study guide was arranged according to the knowledge areas that are covered 

on the airman knowledge test for a Remote Pilot Certificate with a Small Unmanned Aircraft Systems 

Rating as required by Title 14 of the Code of Federal Regulations (14 CFR) part 107, section 107.73(a). 

The knowledge areas are as follows:

1. Applicable regulations relating to small unmanned aircraft system rating privileges, 

limitations, and flight operation;

2. Airspace classification, operating requirements, and flight restrictions affecting small 

unmanned aircraft operation;

3. Aviation weather sources and effects of weather on small unmanned aircraft performance;

4. Small unmanned aircraft loading;

5. Emergency procedures;

6. Crew resource management;

7. Radio communication procedures;

8. Determining the performance of small unmanned aircraft;

9. Physiological effects of drugs and alcohol;

10. Aeronautical decision-making and judgment;

11. Airport operations; and

12. Maintenance and preflight inspection procedures.

Obtaining Assistance from the Federal Aviation Administration (FAA) 

Information can be obtained from the FAA by phone, Internet/e-mail, or mail. To talk to the FAA tollfree 24 hours a day, call 1-866-TELL-FAA (1-866-835-5322). To visit the FAA’s website, go to 

www.faa.gov. Individuals can also e-mail an FAA representative at a local FSDO office by accessing the 

staff e-mail address available via the “Contact FAA” link at the bottom of the FAA home page. Letters 

can be sent to: 

Federal Aviation Administration 

800 Independence Ave, SW 

Washington, DC 20591

FAA Reference Material

The FAA provides a variety of important reference material for the student, as well as the advanced 

civil aviation pilot. In addition to the regulations provided online by the FAA, several other publications 

are available to the user. Almost all reference material is available online at www.faa.gov in 

downloadable format. Commercial aviation publishers also provide published and online reference 

material to further aid the aviation pilot. 

• Aeronautical Information Manual (AIM)

• Handbooks

• Advisory Circulars (ACs)

• Airman Certification Standards

• 14 CFR part 107
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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 3

Chapter 1:

Applicable Regulations 

Be familiar with 14 CFR part 107 and all parts referenced in part 107, as well as AC 107-2.
Remote Pilot – Small Unmanned Aircraft Systems Study Guide 4

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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 5

Chapter 2:

Airspace Classification, Operating Requirements, and Flight Restrictions

Introduction

The two categories of airspace are: regulatory and nonregulatory. Within these two categories, there 

are four types: controlled, uncontrolled, special use, and other airspace. The categories and types of 

airspace are dictated by the complexity or density of aircraft movements, nature of the operations 

conducted within the airspace, the level of safety required, and national and public interest. Figure 2-1

presents a profile view of the dimensions of various classes of airspace. 

Figure 2-1. Airspace profile.

Controlled Airspace 

Controlled airspace is a generic term that covers the different classifications of airspace and defined 

dimensions within which air traffic control (ATC) service is provided in accordance with the airspace 

classification. Controlled airspace that is of concern to the remote pilot is: 

• Class B 

• Class C 

• Class D 

• Class E 

Class B Airspace 

Class B airspace is generally airspace from the surface to 10,000 feet mean sea level (MSL) 

surrounding the nation’s busiest airports in terms of airport operations or passenger enplanements. 

The configuration of each Class B airspace area is individually tailored, consists of a surface area and 

two or more layers (some Class B airspace areas resemble upside-down wedding cakes), and is 

designed to contain all published instrument procedures once an aircraft enters the airspace. A 

remote pilot must receive authorization from ATC before operating in the Class B airspace.
Chapter 2: Airspace Classification, Operating Requirements, and Flight Restrictions 

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 6

Class C Airspace 

Class C airspace is generally airspace from the surface to 4,000 feet above the airport elevation 

(charted in MSL) surrounding those airports that have an operational control tower, are serviced by 

a radar approach control, and have a certain number of instrument flight rules (IFR) operations or 

passenger enplanements. Although the configuration of each Class C area is individually tailored, the 

airspace usually consists of a surface area with a five nautical mile (NM) radius, an outer circle with a 

ten NM radius that extends from 1,200 feet to 4,000 feet above the airport elevation. A remote pilot 

must receive authorization before operating in Class C airspace.

Class D Airspace 

Class D airspace is generally airspace from the surface to 2,500 feet above the airport elevation 

(charted in MSL) surrounding those airports that have an operational control tower. The 

configuration of each Class D airspace area is individually tailored and, when instrument procedures 

are published, the airspace is normally designed to contain the procedures. Arrival extensions for 

instrument approach procedures (IAPs) may be Class D or Class E airspace. A remote pilot must 

receive ATC authorization before operating in Class D airspace.

Class E Airspace 

Class E airspace is the controlled airspace not classified as Class A, B, C, or D airspace. A large 

amount of the airspace over the United States is designated as Class E airspace. This provides 

sufficient airspace for the safe control and separation of aircraft during IFR operations. Chapter 3 of 

the Aeronautical Information Manual (AIM) explains the various types of Class E airspace.

Sectional and other charts depict all locations of Class E airspace with bases below 14,500 feet MSL. 

In areas where charts do not depict a class E base, class E begins at 14,500 feet MSL. In most areas, 

the Class E airspace base is 1,200 feet above ground level (AGL). In many other areas, the Class E 

airspace base is either the surface or 700 feet AGL. Some Class E airspace begins at an MSL altitude 

depicted on the charts, instead of an AGL altitude. Class E airspace typically extends up to, but not 

including, 18,000 feet MSL (the lower limit of Class A airspace). All airspace above FL 600 is Class E 

airspace. 

Federal Airways, which are shown as blue lines on a sectional chart, are usually found within Class E 

airspace. Federal Airways start at 1,200’ AGL and go up to, but, not including 18,000’ MSL. 

In most cases, a remote pilot will not need ATC authorization to operate in Class E airspace.

Uncontrolled Airspace

Class G Airspace 

Uncontrolled airspace or Class G airspace is the portion of the airspace that has not been designated 

as Class A, B, C, D, or E. It is therefore designated uncontrolled airspace. Class G airspace extends 

from the surface to the base of the overlying Class E airspace. A remote pilot will not need ATC 

authorization to operate in Class G airspace.

Special Use Airspace 

Special use airspace or special area of operation (SAO) is the designation for airspace in which certain 

activities must be confined, or where limitations may be imposed on aircraft operations that are not 

part of those activities. Certain special use airspace areas can create limitations on the mixed use of 

airspace. The special use airspace depicted on instrument charts includes the area name or number, 
Chapter 2: Airspace Classification, Operating Requirements, and Flight Restrictions 

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 7 

effective altitude, time and weather conditions of operation, the controlling agency, and the chart 

panel location. On National Aeronautical Charting Group (NACG) en route charts, this information is 

available on one of the end panels. Special use airspace usually consists of: 

• Prohibited areas 

• Restricted areas 

• Warning areas 

• Military operation areas (MOAs) 

• Alert areas 

• Controlled firing areas (CFAs) 

Prohibited Areas 

Prohibited areas contain airspace of 

defined dimensions within which the 

flight of aircraft is prohibited. Such 

areas are established for security or 

other reasons associated with the 

national welfare. These areas are 

published in the Federal Register and 

are depicted on aeronautical charts. 

The area is charted as a “P” followed by 

a number (e.g., P-40). Examples of 

prohibited areas include Camp David 

and the National Mall in Washington, 

D.C., where the White House and the 

Congressional buildings are located. 

[Figure 2-2] 

Restricted Areas 

Restricted areas are areas where 

operations are hazardous to 

nonparticipating aircraft and contain 

airspace within which the flight of aircraft, 

while not wholly prohibited, is subject to 

restrictions. Activities within these areas 

must be confined because of their nature, 

or limitations may be imposed upon 

aircraft operations that are not a part of 

those activities, or both. Restricted areas 

denote the existence of unusual, often 

invisible, hazards to aircraft (e.g., artillery 

firing, aerial gunnery, or guided missiles). 

Penetration of restricted areas without 

authorization from the using or 

controlling agency may be extremely 

hazardous to the aircraft.

Figure 2-2. An example of a prohibited area, P-40 around Camp David.

Figure 2-3. Restricted areas on a sectional chart.
Chapter 2: Airspace Classification, Operating Requirements, and Flight Restrictions 

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 8 

1. If the restricted area is not active and has been released to the FAA, the ATC facility allows 

the aircraft to operate in the restricted airspace without issuing specific clearance for it to do 

so. 

2. If the restricted area is active and has not been released to the FAA, the ATC facility issues a 

clearance that ensures the aircraft avoids the restricted airspace. 

Restricted areas are charted with an “R” followed by a number (e.g., R-4401) and are depicted on 

the en route chart appropriate for use at the altitude or flight level (FL) being flown. [Figure 10-1] 

Restricted area information can be obtained on the back of the chart. 

Warning Areas 

Warning areas are similar in nature to 

restricted areas; however, the United 

States government does not have sole 

jurisdiction over the airspace. A warning 

area is airspace of defined dimensions, 

extending from 3 NM outward from the 

coast of the United States, containing 

activity that may be hazardous to 

nonparticipating aircraft. The purpose of 

such areas is to warn nonparticipating 

pilots of the potential danger. A warning 

area may be located over domestic or 

international waters or both. The airspace 

is designated with a “W” followed by a 

number (e.g., W-237). [Figure 2-4] 

Military Operation Areas (MOAs)

MOAs consist of airspace with 

defined vertical and lateral 

limits established for the 

purpose of separating certain 

military training activities from 

IFR traffic. Whenever an MOA 

is being used, nonparticipating 

IFR traffic may be cleared 

through an MOA if IFR 

separation can be provided by 

ATC. Otherwise, ATC reroutes 

or restricts nonparticipating IFR 

traffic. MOAs are depicted on 

sectional, VFR terminal area, 

and en route low altitude 

charts and are not numbered 

(e.g., “Camden Ridge MOA”).

[Figure 2-5] However, the MOA 

Figure 2-4. Requirements for airspace operations.

Figure 2-5. Camden Ridge MOA is an example of a military operations area.
Chapter 2: Airspace Classification, Operating Requirements, and Flight Restrictions 

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 9 

is also further defined on the back of the sectional charts with times of operation, altitudes affected, 

and the controlling agency. 

Alert Areas 

Alert areas are depicted on aeronautical charts with an “A” followed by a number (e.g., A-211) to 

inform nonparticipating pilots of areas that may contain a high volume of pilot training or an 

unusual type of aerial activity. Pilots should exercise caution in alert areas. All activity within an alert 

area shall be conducted in accordance with regulations, without waiver, and pilots of participating 

aircraft, as well as pilots transiting the area, shall be equally responsible for collision avoidance. 

[Figure 2-6] 

Figure 2-6. Alert area (A-211).

Controlled Firing Areas (CFAs) 

CFAs contain activities that, if not conducted in a controlled environment, could be hazardous to 

nonparticipating aircraft. The difference between CFAs and other special use airspace is that 

activities must be suspended when a spotter aircraft, radar, or ground lookout position indicates an 

aircraft might be approaching the area. There is no need to chart CFAs since they do not cause a 

nonparticipating aircraft to change its flight path. 

Other Airspace Areas

“Other airspace areas” is a general term referring to the majority of the remaining airspace. It includes: 

• Local airport advisory (LAA) 

• Military training route (MTR) 

• Temporary flight restriction (TFR) 

• Parachute jump aircraft operations 

• Published VFR routes 

• Terminal radar service area (TRSA) 

• National security area (NSA) 

• Air Defense Identification Zones (ADIZ) land and water based and need for Defense VFR

(DVFR) flight plan to operate VFR in this airspace 

• Flight Restricted Zones (FRZ) in vicinity of Capitol and White House 
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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 10

• Wildlife Areas/Wilderness Areas/National Parks and request to operate above 2,000 AGL 

• National Oceanic and Atmospheric Administration (NOAA) Marine Areas off the coast with

requirement to operate above 2,000 AGL 

• Tethered Balloons for observation and weather recordings that extend on cables up to 60,000 

Local Airport Advisory (LAA) 

An advisory service provided by Flight Service facilities, which are located on the landing airport, 

using a discrete ground-to-air frequency or the tower frequency when the tower is closed. LAA 

services include local airport advisories, automated weather reporting with voice broadcasting, and 

a continuous Automated Surface Observing System (ASOS)/Automated Weather Observing Station 

(AWOS) data display, other continuous direct reading instruments, or manual observations available 

to the specialist. 

Military Training Routes (MTRs) 

MTRs are routes used by military aircraft to maintain proficiency in tactical flying. These routes are 

usually established below 10,000 feet MSL for operations at speeds in excess of 250 knots. Some 

route segments may be defined at higher altitudes for purposes of route continuity. Routes are 

identified as IFR (IR), and VFR (VR), followed by a number. [Figure 2-7] MTRs with no segment above 

1,500 feet AGL are identified by four number characters (e.g., IR1206, VR1207). MTRs that include 

one or more segments above 1,500 feet AGL are identified by three number characters (e.g., IR206, 

VR207). IFR low altitude en route charts depict all IR routes and all VR routes that accommodate 

operations above 1,500 feet AGL. IR routes are conducted in accordance with IFR regardless of 

weather conditions. VFR sectional charts depict military training activities, such as IR, VR, MOA, 

restricted area, warning area, and alert area information. 

Figure 2-7. Military training route (MTR) chart symbols.

Temporary Flight Restrictions (TFR) 

A flight data center (FDC) Notice to Airmen (NOTAM) is issued to designate a TFR. The NOTAM 

begins with the phrase “FLIGHT RESTRICTIONS” followed by the location of the temporary 

restriction, effective time period, area defined in statute miles, and altitudes affected. The NOTAM 
Chapter 2: Airspace Classification, Operating Requirements, and Flight Restrictions 

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 11

also contains the FAA coordination facility and telephone number, the reason for the restriction, 

and any other information deemed appropriate. The pilot should check the NOTAMs as part of flight 

planning. 

Some of the purposes for establishing a TFR are: 

• Protect persons and property in the air or on the surface from an existing or imminent

hazard. 

• Provide a safe environment for the operation of disaster relief aircraft. 

• Prevent an unsafe congestion of sightseeing aircraft above an incident or event, that may

generate a high degree of public interest. 

• Protect declared national disasters for humanitarian reasons in the State of Hawaii. 

• Protect the President, Vice President, or other public figures. 

• Provide a safe environment for space agency operations. 

Since the events of September 11, 2001, the use of TFRs has become much more common. There 

have been a number of incidents of aircraft incursions into TFRs that have resulted in pilots 

undergoing security investigations and certificate suspensions. It is a pilot’s responsibility to be 

aware of TFRs in their proposed area of flight. One way to check is to visit the FAA website, 

www.tfr.faa.gov, and verify that there is not a TFR in the area. 

Parachute Jump Aircraft Operations 

Parachute jump aircraft operations are published in the Chart Supplement U.S. (formerly 

Airport/Facility Directory). Sites that are used frequently are depicted on sectional charts. 

Published VFR Routes 

Published VFR routes are for transitioning around, under, or through some complex airspace. Terms 

such as VFR flyway, VFR corridor, Class B airspace VFR transition route, and terminal area VFR route 

have been applied to such routes. These routes are generally found on VFR terminal area planning 

charts. 

Terminal Radar Service Areas (TRSAs) 

TRSAs are areas where participating pilots can receive additional radar services. The purpose of the 

service is to provide separation between all IFR operations and participating VFR aircraft. 

The primary airport(s) within the TRSA become(s) Class D airspace. The remaining portion of the 

TRSA overlies other controlled airspace, which is normally Class E airspace beginning at 700 or 1,200 

feet and established to transition to/ from the en route/terminal environment. TRSAs are depicted 

on VFR sectional charts and terminal area charts with a solid black line and altitudes for each 

segment. The Class D portion is charted with a blue segmented line. Participation in TRSA services is 

voluntary; however, pilots operating under VFR are encouraged to contact the radar approach 

control and take advantage of TRSA service. 

National Security Areas (NSAs) 

NSAs consist of airspace of defined vertical and lateral dimensions established at locations where 

there is a requirement for increased security and safety of ground facilities. Flight in NSAs may be 

temporarily prohibited by regulation under the provisions of Title 14 of the Code of Federal 

Regulations (14 CFR) part 99 and prohibitions are disseminated via NOTAM. Pilots are requested to 

voluntarily avoid flying through these depicted areas. 
Chapter 2: Airspace Classification, Operating Requirements, and Flight Restrictions 

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 12

Air Traffic Control and the National Airspace System

The primary purpose of the ATC system is to prevent a collision between aircraft operating in the 

system and to organize and expedite the flow of traffic. In addition to its primary function, the ATC 

system has the capability to provide (with certain limitations) additional services. The ability to provide 

additional services is limited by many factors, such as the volume of traffic, frequency congestion, 

quality of radar, controller workload, higher priority duties, and the pure physical inability to scan and 

detect those situations that fall in this category. It is recognized that these services cannot be provided 

in cases in which the provision of services is precluded by the above factors. 

Consistent with the aforementioned conditions, controllers shall provide additional service procedures 

to the extent permitted by higher priority duties and other circumstances. The provision of additional 

services is not optional on the part of the controller, but rather is required when the work situation 

permits. Provide ATC service in accordance with the procedures and minima in this order except when 

other procedures/minima are prescribed in a letter of agreement, FAA directive, or a military 

document.

Operating Rules and Pilot/Equipment Requirements 

The safety of flight is a top priority of all pilots and the responsibilities associated with operating an 

aircraft should always be taken seriously. The air traffic system maintains a high degree of safety 

and efficiency with strict regulatory oversight of the FAA. Pilots fly in accordance with regulations 

that have served the United States well, as evidenced by the fact that the country has the safest 

aviation system in the world.

All aircraft operating in today’s National Airspace System (NAS) has complied with the CFR governing 

its certification and maintenance; all pilots operating today have completed rigorous pilot 

certification training and testing. Of equal importance is the proper execution of preflight planning, 

aeronautical decision-making (ADM) and risk management. ADM involves a systematic approach to 

risk assessment and stress management in aviation, illustrates how personal attitudes can influence 

decision-making, and how those attitudes can be modified to enhance safety. More detailed 

information regarding ADM and risk mitigation can be found in Chapter 10, “Aeronautical DecisionMaking and Judgment,” of this study guide.

Pilots also comply with very strict FAA general operating and flight rules as outlined in the CFR, 

including the FAA’s important “see and avoid” mandate. These regulations provide the historical 

foundation of the FAA regulations governing the aviation system and the individual classes of 

airspace.

Visual Flight Rules (VFR) Terms & Symbols

Remote pilots need to be familiar with the following information from the FAA Aeronautical Chart 

User’s Guide website: 

• All information on the VFR Terms tab

• The following sections under “VFR Aeronautical Chart Symbols” on the VFR Symbols tab:

o Airports

o Airspace Information

o Navigational and Procedural Information

o Chart Limits

o Culture
Chapter 2: Airspace Classification, Operating Requirements, and Flight Restrictions 

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 13

o Hydrography

o Relief

Notices to Airmen (NOTAMs) 

Notices to Airmen, or NOTAMs, are time-critical aeronautical information either temporary in nature 

or not sufficiently known in advance to permit publication on aeronautical charts or in other 

operational publications. The information receives immediate dissemination via the National Notice to 

Airmen (NOTAM) System. NOTAMs contain current notices to airmen that are considered essential to 

the safety of flight, as well as supplemental data affecting other operational publications. There are 

many different reasons that NOTAMs are issued. Following are some of those reasons: 

• Hazards, such as air shows, parachute jumps, kite flying, and rocket launches

• Flights by important people such as heads of state

• Inoperable lights on tall obstructions

• Temporary erection of obstacles near airfields

• Passage of flocks of birds through airspace (a NOTAM in this category is known as a BIRDTAM)

NOTAMs are available in printed form through subscription from the Superintendent of Documents

or online at PilotWeb, which provides access to current NOTAM information. Local airport NOTAMs 

can be obtained online from various websites. Some examples are www.fltplan.com and 

www.aopa.org/whatsnew/notams.html. Most sites require a free registration and acceptance of 

terms but offer pilots updated NOTAMs and TFRs.
Chapter 2: Airspace Classification, Operating Requirements, and Flight Restrictions 

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 14

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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 15

Chapter 3a:

Aviation Weather Sources

Introduction

In aviation, weather service is a combined effort of the National Weather Service (NWS), Federal 

Aviation Administration (FAA), Department of Defense (DOD), other aviation groups, and individuals. 

Because of the increasing need for worldwide weather services, foreign weather organizations also 

provide vital input. While weather forecasts are not 100 percent accurate, meteorologists, through 

careful scientific study and computer modeling, have the ability to predict weather patterns, trends, 

and characteristics with increasing accuracy. Through a complex system of weather services, 

government agencies, and independent weather observers, pilots and other aviation professionals 

receive the benefit of this vast knowledge base in the form of up-to-date weather reports and 

forecasts. These reports and forecasts enable pilots to make informed decisions regarding weather and 

flight safety before and during a flight.

Surface Aviation Weather Observations 

Surface aviation weather observations are a compilation of elements of the current weather at 

individual ground stations across the United States. The network is made up of government and 

privately contracted facilities that provide continuous up-to-date weather information. Automated 

weather sources, such as the Automated Weather Observing Systems (AWOS), Automated Surface 

Observing Systems (ASOS), as well as other automated facilities, also play a major role in the gathering 

of surface observations. 

Surface observations provide local weather conditions and other relevant information for a specific 

airport. This information includes the type of report, station identifier, date and time, modifier (as 

required), wind, visibility, runway visual range (RVR), weather phenomena, sky condition, 

temperature/dew point, altimeter reading, and applicable remarks. The information gathered for the 

surface observation may be from a person, an automated station, or an automated station that is 

updated or enhanced by a weather observer. In any form, the surface observation provides valuable 

information about individual airports around the country. These reports cover a small area and will be 

beneficial to the remote pilot.

Aviation Weather Reports 

Aviation weather reports are designed to give accurate depictions of current weather conditions. Each 

report provides current information that is updated at different times. Some typical reports are 

METARs and PIREPs. To view a weather report, go to http://www.aviationweather.gov/.

Aviation Routine Weather Report (METAR) 

A METAR is an observation of current surface weather reported in a standard international format. 

METARs are issued on a regularly scheduled basis unless significant weather changes have occurred. 

A special METAR (SPECI) can be issued at any time between routine METAR reports. 

Example: METAR KGGG 161753Z AUTO 14021G26KT 3/4SM +TSRA BR BKN008 OVC012CB 

18/17 A2970 RMK PRESFR 
Chapter 3a: Aviation Weather Sources

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 16

A typical METAR report contains the following information in sequential order: 

1. Type of report—there are two types of METAR reports. The first is the routine METAR report 

that is transmitted on a regular time interval. The second is the aviation selected SPECI. This 

is a special report that can be given at any time to update the METAR for rapidly changing 

weather conditions, aircraft mishaps, or other critical information. 

2. Station identifier—a four-letter code as established by the International Civil Aviation 

Organization (ICAO). In the 48 contiguous states, a unique three-letter identifier is preceded 

by the letter “K.” For example, Gregg County Airport in Longview, Texas, is identified by the 

letters “KGGG,” K being the country designation and GGG being the airport identifier. In 

other regions of the world, including Alaska and Hawaii, the first two letters of the four-letter 

ICAO identifier indicate the region, country, or state. Alaska identifiers always begin with the 

letters “PA” and Hawaii identifiers always begin with the letters “PH.” Station identifiers can 

be found by searching various websites such as DUATS and NOAA's Aviation Weather 

Aviation Digital Data Services (ADDS). 

3. Date and time of report—depicted in a six-digit group (161753Z). The first two digits are the 

date. The last four digits are the time of the METAR/SPECI, which is always given in 

coordinated universal time (UTC). A “Z” is appended to the end of the time to denote the 

time is given in Zulu time (UTC) as opposed to local time. 

4. Modifier—denotes that the METAR/SPECI came from an automated source or that the report 

was corrected. If the notation “AUTO” is listed in the METAR/SPECI, the report came from an 

automated source. It also lists “AO1” (for no precipitation discriminator) or “AO2” (with 

precipitation discriminator) in the “Remarks” section to indicate the type of precipitation 

sensors employed at the automated station. When the modifier “COR” is used, it identifies a 

corrected report sent out to replace an earlier report that contained an error (for example: 

METAR KGGG 161753Z COR). 

5. Wind—reported with five digits (14021KT) unless the speed is greater than 99 knots, in which 

case the wind is reported with six digits. The first three digits indicate the direction the true 

wind is blowing from in tens of degrees. If the wind is variable, it is reported as “VRB.” The 

last two digits indicate the speed of the wind in knots unless the wind is greater than 99 

knots, in which case it is indicated by three digits. If the winds are gusting, the letter “G” 

follows the wind speed (G26KT). After the letter “G,” the peak gust recorded is provided. If 

the wind direction varies more than 60° and the wind speed is greater than six knots, a 

separate group of numbers, separated by a “V,” will indicate the extremes of the wind 

directions. 

6. Visibility—the prevailing visibility (3⁄4 SM) is reported in statute miles as denoted by the letters 

“SM.” It is reported in both miles and fractions of miles. At times, runway visual range (RVR) 

is reported following the prevailing visibility. RVR is the distance a pilot can see down the 

runway in a moving aircraft. When RVR is reported, it is shown with an R, then the runway 

number followed by a slant, then the visual range in feet. For example, when the RVR is 

reported as R17L/1400FT, it translates to a visual range of 1,400 feet on runway 17 left. 

7. Weather—can be broken down into two different categories: qualifiers and weather 

phenomenon (+TSRA BR). First, the qualifiers of intensity, proximity, and the descriptor of the 

weather are given. The intensity may be light (–), moderate ( ), or heavy (+). Proximity only 

depicts weather phenomena that are in the airport vicinity. The notation “VC” indicates a 

specific weather phenomenon is in the vicinity of five to ten miles from the airport. 

Descriptors are used to describe certain types of precipitation and obscurations. Weather 
Chapter 3a: Aviation Weather Sources

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 17

phenomena may be reported as being precipitation, obscurations, and other phenomena, 

such as squalls or funnel clouds. Descriptions of weather phenomena as they begin or end 

and hailstone size are also listed in the “Remarks” sections of the report. [Figure 3-1] 

Figure 3-1. Descriptors and weather phenomena used in a typical METAR.

8. Sky condition—always reported in the sequence of amount, height, and type or indefinite 

ceiling/height (vertical visibility) (BKN008 OVC012CB, VV003). The heights of the cloud bases 

are reported with a three-digit number in hundreds of feet AGL. Clouds above 12,000 feet are 

not detected or reported by an automated station. The types of clouds, specifically towering 

cumulus (TCU) or cumulonimbus (CB) clouds, are reported with their height. Contractions are 

used to describe the amount of cloud coverage and obscuring phenomena. The amount of 

sky coverage is reported in eighths of the sky from horizon to horizon. [Figure 3-2]

Figure 3-2. Reportable contractions for sky condition.

9. Temperature and dew point—the air temperature and dew point are always given in degrees 

Celsius (C) or (18/17). Temperatures below 0 °C are preceded by the letter “M” to indicate 

minus. 

10. Altimeter setting—reported as inches of mercury ("Hg) in a four-digit number group (A2970). 

It is always preceded by the letter “A.” Rising or falling pressure may also be denoted in the 

“Remarks” sections as “PRESRR” or “PRESFR,” respectively. 
Chapter 3a: Aviation Weather Sources

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 18

11. Zulu time—a term used in aviation for UTC, which places the entire world on one time 

standard. 

12. Remarks—the remarks section always begins with the letters “RMK.” Comments may or may 

not appear in this section of the METAR. The information contained in this section may 

include wind data, variable visibility, beginning and ending times of particular phenomenon, 

pressure information, and various other information deemed necessary. An example of a 

remark regarding weather phenomenon that does not fit in any other category would be: 

OCNL LTGICCG. This translates as occasional lightning in the clouds and from cloud to ground. 

Automated stations also use the remarks section to indicate the equipment needs 

maintenance. 

Example: METAR KGGG 161753Z AUTO 14021G26KT 3/4SM +TSRA BR BKN008 OVC012CB 

18/17 A2970 RMK PRESFR

Explanation: Routine METAR for Gregg County Airport for the 16th day of the month at 1753Z 

automated source. Winds are 140 at 21 knots gusting to 26. Visibility is 3⁄4 statute 

mile. Thunderstorms with heavy rain and mist. Ceiling is broken at 800 feet, overcast 

at 1,200 feet with cumulonimbus clouds. Temperature 18 °C and dew point 17 °C. 

Barometric pressure is 29.70 "Hg and falling rapidly.

Aviation Forecasts 

Observed weather condition reports are often used in the creation of forecasts for the same area. A 

variety of different forecast products are produced and designed to be used in the preflight planning 

stage. The printed forecasts that pilots need to be familiar with are the terminal aerodrome forecast 

(TAF), aviation area forecast (FA), inflight weather advisories (Significant Meteorological Information 

(SIGMET), Airman’s Meteorological Information (AIRMET)), and the winds and temperatures aloft 

forecast (FB). 

Terminal Aerodrome Forecasts (TAF) 

A TAF is a report established for the five statute mile radius around an airport. TAF reports are 

usually given for larger airports. Each TAF is valid for a 24 or 30-hour time period and is updated four 

times a day at 0000Z, 0600Z, 1200Z, and 1800Z. The TAF utilizes the same descriptors and 

abbreviations as used in the METAR report. These weather reports can be beneficial to the remote 

pilot for flight planning purposes. The TAF includes the following information in sequential order: 

1. Type of report—a TAF can be either a routine forecast (TAF) or an amended forecast (TAF 

AMD). 

2. ICAO station identifier—the station identifier is the same as that used in a METAR. 

3. Date and time of origin—time and date (081125Z) of TAF origination is given in the sixnumber code with the first two being the date, the last four being the time. Time is always 

given in UTC as denoted by the Z following the time block. 

4. Valid period dates and times—The TAF valid period (0812/0912) follows the date/time of 

forecast origin group. Scheduled 24 and 30 hour TAFs are issued four times per day, at 0000, 

0600, 1200, and 1800Z. The first two digits (08) are the day of the month for the start of the 

TAF. The next two digits (12) are the starting hour (UTC). 09 is the day of the month for the 

end of the TAF, and the last two digits (12) are the ending hour (UTC) of the valid period. A 

forecast period that begins at midnight UTC is annotated as 00. If the end time of a valid 
Chapter 3a: Aviation Weather Sources

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 19

period is at midnight UTC, it is annotated as 24. For example, a 00Z TAF issued on the 9th of 

the month and valid for 24 hours would have a valid period of 0900/0924. 

5. Forecast wind—the wind direction and speed forecast are coded in a five-digit number group. 

An example would be 15011KT. The first three digits indicate the direction of the wind in 

reference to true north. The last two digits state the wind speed in knots appended with 

“KT.” Like the METAR, winds greater than 99 knots are given in three digits. 

6. Forecast visibility—given in statute miles and may be in whole numbers or fractions. If the 

forecast is greater than six miles, it is coded as “P6SM.” 

7. Forecast significant weather—weather phenomena are coded in the TAF reports in the same 

format as the METAR. 

8. Forecast sky condition—given in the same format as the METAR. Only CB clouds are forecast 

in this portion of the TAF report as opposed to CBs and towering cumulus in the METAR. 

9. Forecast change group—for any significant weather change forecast to occur during the TAF 

time period, the expected conditions and time period are included in this group. This 

information may be shown as from (FM), and temporary (TEMPO). “FM” is used when a rapid 

and significant change, usually within an hour, is expected. “TEMPO” is used for temporary 

fluctuations of weather, expected to last less than 1 hour. 

10. PROB30—a given percentage that describes the probability of thunderstorms and 

precipitation occurring in the coming hours. This forecast is not used for the first 6 hours of 

the 24-hour forecast. 

Example: TAF KPIR 111130Z 1112/1212 TEMPO 1112/1114 5SM BR FM1500 16015G25KT P6SM 

SCT040 BKN250 FM120000 14012KT P6SM BKN080 OVC150 PROB30 1200/1204 3SM 

TSRA BKN030CB FM120400 1408KT P6SM SCT040 OVC080 TEMPO 1204/1208 3SM 

TSRA OVC030CB 

Explanation: Routine TAF for Pierre, South Dakota...on the 11th day of the month, at 1130Z...valid 

for 24 hours from 1200Z on the 11th to 1200Z on the 12th...wind from 150° at 12 

knots... visibility greater than 6 SM...broken clouds at 9,000 feet... temporarily, 

between 1200Z and 1400Z, visibility 5 SM in mist...from 1500Z winds from 160° at 15 

knots, gusting to 25 knots visibility greater than 6 SM...clouds scattered at 4,000 feet 

and broken at 25,000 feet...from 0000Z wind from 140° at 12 knots...visibility greater 

than 6 SM...clouds broken at 8,000 feet, overcast at 15,000 feet...between 0000Z and 

0400Z, there is 30 percent probability of visibility 3 SM...thunderstorm with moderate 

rain showers...clouds broken at 3,000 feet with cumulonimbus clouds...from 

0400Z...winds from 140° at 8 knots...visibility greater than 6 miles...clouds at 4,000 

scattered and overcast at 8,000... temporarily between 0400Z and 0800Z...visibility 3 

miles... thunderstorms with moderate rain showers...clouds overcast at 3,000 feet 

with cumulonimbus clouds...end of report (=).

Convective Significant Meteorological Information (WST) 

Convective SIGMETs are issued for severe thunderstorms with surface winds greater than 50 knots, hail 

at the surface greater than or equal to 3⁄4 inch in diameter, or tornadoes. They are also issued to advise 

pilots of embedded thunderstorms, lines of thunderstorms, or thunderstorms with heavy or greater 

precipitation that affect 40 percent or more of a 3,000 square mile or greater region. A remote pilot 

will find these weather alerts helpful for flight planning.
Chapter 3a: Aviation Weather Sources

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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 21

Chapter 3b:

Effects of Weather on Small Unmanned Aircraft Performance

Introduction

This chapter discusses the factors that affect aircraft performance, which include the aircraft weight, 

atmospheric conditions, runway environment, and the fundamental physical laws governing the forces 

acting on an aircraft.

Since the characteristics of the atmosphere have a major effect on performance, it is necessary to 

review two dominant factors—pressure and temperature. 

Density Altitude 

The more appropriate term for correlating aerodynamic performance in the nonstandard atmosphere 

is density altitude—the altitude in the standard atmosphere corresponding to a particular value of air 

density. 

As the density of the air increases (lower density altitude), aircraft performance increases. Conversely, 

as air density decreases (higher density altitude), aircraft performance decreases. A decrease in air 

density means a high density altitude; an increase in air density means a lower density altitude. Density 

altitude has a direct effect on aircraft performance.

Air density is affected by changes in altitude, temperature, and humidity. High density altitude refers to 

thin air while low density altitude refers to dense air. The conditions that result in a high density 

altitude are high elevations, low atmospheric pressures, high temperatures, high humidity, or some 

combination of these factors. Lower elevations, high atmospheric pressure, low temperatures, and low 

humidity are more indicative of low density altitude.

Effects of Pressure on Density 

Since air is a gas, it can be compressed or expanded. When air is compressed, a greater amount of 

air can occupy a given volume. Conversely, when pressure on a given volume of air is decreased, the 

air expands and occupies a greater space. That is, the original column of air at a lower pressure 

contains a smaller mass of air. In other words, the density is decreased. In fact, density is directly 

proportional to pressure. If the pressure is doubled, the density is doubled, and if the pressure is 

lowered, so is the density. This statement is true only at a constant temperature. 

Effects of Temperature on Density 

Increasing the temperature of a substance decreases its density. Conversely, decreasing the 

temperature increases the density. Thus, the density of air varies inversely with temperature. This 

statement is true only at a constant pressure. 

In the atmosphere, both temperature and pressure decrease with altitude and have conflicting 

effects upon density. However, the fairly rapid drop in pressure as altitude is increased usually has 

the dominant effect. Hence, pilots can expect the density to decrease with altitude. 

Effects of Humidity (Moisture) on Density 

The preceding paragraphs are based on the presupposition of perfectly dry air. In reality, it is never 

completely dry. The small amount of water vapor suspended in the atmosphere may be negligible 
Chapter 3b: Effects of Weather on Small Unmanned Aircraft Performance

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 22

under certain conditions, but in other conditions humidity may become an important factor in the 

performance of an aircraft. Water vapor is lighter than air; consequently, moist air is lighter than dry 

air. Therefore, as the water content of the air increases, the air becomes less dense, increasing 

density altitude and decreasing performance. It is lightest or least dense when, in a given set of 

conditions, it contains the maximum amount of water vapor. 

Humidity, also called relative humidity, refers to the amount of water vapor contained in the 

atmosphere and is expressed as a percentage of the maximum amount of water vapor the air can 

hold. This amount varies with the temperature; warm air can hold more water vapor, while colder 

air can hold less. Perfectly dry air that contains no water vapor has a relative humidity of zero 

percent, while saturated air that cannot hold any more water vapor has a relative humidity of 100 

percent. Humidity alone is usually not considered an essential factor in calculating density altitude 

and aircraft performance; however, it does contribute.

Performance 

Performance is a term used to describe the ability of an aircraft to accomplish certain things that make 

it useful for certain purposes. 

The primary factors most affected by performance are the takeoff and landing distance, rate of climb, 

ceiling, payload, range, speed, maneuverability, stability, and fuel economy.

Climb Performance Factors 

Since weight, altitude and configuration changes affect excess thrust and power, they also affect 

climb performance. Climb performance is directly dependent upon the ability to produce either 

excess thrust or excess power. 

Weight has a very pronounced effect on aircraft performance. If weight is added to an aircraft, it 

must fly at a higher angle of attack (AOA) to maintain a given altitude and speed. This increases the 

induced drag of the wings, as well as the parasite drag of the aircraft. Increased drag means that 

additional thrust is needed to overcome it, which in turn means that less reserve thrust is available 

for climbing. Aircraft designers go to great lengths to minimize the weight, since it has such a 

marked effect on the factors pertaining to performance. 

A change in an aircraft’s weight produces a twofold effect on climb performance. An increase in 

altitude also increases the power required and decreases the power available. Therefore, the climb 

performance of an aircraft diminishes with altitude.

Measurement of Atmosphere Pressure 

To provide a common reference, the International Standard Atmosphere (ISA) has been established. 

These standard conditions are the basis for most aircraft performance data. Standard sea level 

pressure is defined as 29.92 "Hg and a standard temperature of 59 °F (15 °C). Atmospheric pressure is 

also reported in millibars (mb), with 1 "Hg equal to approximately 34 mb. Standard sea level pressure is 

1,013.2 mb. Typical mb pressure readings range from 950.0 to 1,040.0 mb. Surface charts, high and low 

pressure centers, and hurricane data are reported using mb. 

Since weather stations are located around the globe, all local barometric pressure readings are 

converted to a sea level pressure to provide a standard for records and reports. To achieve this, each 

station converts its barometric pressure by adding approximately 1 "Hg for every 1,000 feet of 
Chapter 3b: Effects of Weather on Small Unmanned Aircraft Performance

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 23

elevation. For example, a station at 5,000 feet above sea level, with a reading of 24.92 "Hg, reports a 

sea level pressure reading of 29.92 "Hg.

By tracking barometric pressure trends across a large area, weather forecasters can more accurately 

predict movement of pressure systems and the associated weather. For example, tracking a pattern of 

rising pressure at a single weather station generally indicates the approach of fair weather. Conversely, 

decreasing or rapidly falling pressure usually indicates approaching bad weather and, possibly, severe 

storms.

Effect of Obstructions on Wind 

Another atmospheric hazard exists that can create problems for pilots. Obstructions on the ground 

affect the flow of wind and can be an unseen danger. Ground topography and large buildings can break 

up the flow of the wind and create wind gusts that change rapidly in direction and speed. These 

obstructions range from man-made structures, like hangars, to large natural obstructions, such as 

mountains, bluffs, or canyons. 

The intensity of the turbulence associated with ground obstructions depends on the size of the 

obstacle and the primary velocity of the wind. This can affect the performance of any aircraft and can 

present a very serious hazard.

This same condition is even more noticeable when flying in mountainous regions. [Figure 3-3] While 

the wind flows smoothly up the windward side of the mountain and the upward currents help to carry 

an aircraft over the peak of the mountain, the wind on the leeward side does not act in a similar 

manner. As the air flows down the leeward side of the mountain, the air follows the contour of the 

terrain and is increasingly turbulent. This tends to push an aircraft into the side of a mountain. The 

stronger the wind, the greater the downward pressure and turbulence become.

Figure 3-3. Turbulence in mountainous regions.

Low-Level Wind Shear 

Wind shear is a sudden, drastic change in wind speed and/or direction over a very small area. Wind 

shear can subject an aircraft to violent updrafts and downdrafts, as well as abrupt changes to the 

horizontal movement of the aircraft. While wind shear can occur at any altitude, low-level wind shear 

is especially hazardous due to the proximity of an aircraft to the ground. Low-level wind shear is 

commonly associated with passing frontal systems, thunderstorms, temperature inversions, and strong 

upper level winds (greater than 25 knots). 
Chapter 3b: Effects of Weather on Small Unmanned Aircraft Performance

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 24

Wind shear is dangerous to an aircraft. It can rapidly change the performance of the aircraft and 

disrupt the normal flight attitude. For example, a tailwind quickly changing to a headwind causes an 

increase in airspeed and performance. Conversely, a headwind changing to a tailwind causes a 

decrease in airspeed and performance. In either case, a pilot must be prepared to react immediately to 

these changes to maintain control of the aircraft. 

The most severe type of low-level wind shear, a microburst, is associated with convective precipitation 

into dry air at cloud base. Microburst activity may be indicated by an intense rain shaft at the surface 

but virga at cloud base and a ring of blowing dust is often the only visible clue. A typical microburst has 

a horizontal diameter of 1–2 miles and a nominal depth of 1,000 feet. The lifespan of a microburst is 

about 5–15 minutes during which time it can produce downdrafts of up to 6,000 feet per minute (fpm) 

and headwind losses of 30–90 knots, seriously degrading performance. It can also produce strong 

turbulence and hazardous wind direction changes. During an inadvertent microburst encounter, the 

small UA may first experience a performance-increasing headwind, followed by performancedecreasing downdrafts, followed by a rapidly increasing tailwind. This can result in terrain impact or 

flight dangerously close to the ground. An encounter during approach involves the same sequence of 

wind changes and could force the small UA to the ground short of the intended landing area.

It is important to remember that wind shear can affect any flight at any altitude. While wind shear may 

be reported, it often remains undetected and is a silent danger to aviation. Always be alert to the 

possibility of wind shear, especially when flying in and around thunderstorms and frontal systems.

Atmospheric Stability 

The stability of the atmosphere depends on its ability to resist vertical motion. A stable atmosphere 

makes vertical movement difficult, and small vertical disturbances dampen out and disappear. In an 

unstable atmosphere, small vertical air movements tend to become larger, resulting in turbulent 

airflow and convective activity. Instability can lead to significant turbulence, extensive vertical clouds, 

and severe weather. 

The combination of moisture and temperature determine the stability of the air and the resulting 

weather. Cool, dry air is very stable and resists vertical movement, which leads to good and generally 

clear weather. The greatest instability occurs when the air is moist and warm, as it is in the tropical 

regions in the summer. Typically, thunderstorms appear on a daily basis in these regions due to the 

instability of the surrounding air. 

Inversion 

As air rises and expands in the atmosphere, the temperature decreases. There is an atmospheric 

anomaly that can occur; however, that changes this typical pattern of atmospheric behavior. When 

the temperature of the air rises with altitude, a temperature inversion exists. Inversion layers are 

commonly shallow layers of smooth, stable air close to the ground. The temperature of the air 

increases with altitude to a certain point, which is the top of the inversion. The air at the top of the 

layer acts as a lid, keeping weather and pollutants trapped below. If the relative humidity of the air 

is high, it can contribute to the formation of clouds, fog, haze, or smoke resulting in diminished 

visibility in the inversion layer. 

Surface-based temperature inversions occur on clear, cool nights when the air close to the ground is 

cooled by the lowering temperature of the ground. The air within a few hundred feet of the surface 
Chapter 3b: Effects of Weather on Small Unmanned Aircraft Performance

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 25

becomes cooler than the air above it. Frontal inversions occur when warm air spreads over a layer of 

cooler air, or cooler air is forced under a layer of warmer air.

Temperature/Dew Point Relationship 

The relationship between dew point and temperature defines the concept of relative humidity. The 

dew point, given in degrees, is the temperature at which the air can hold no more moisture. When the 

temperature of the air is reduced to the dew point, the air is completely saturated and moisture begins 

to condense out of the air in the form of fog, dew, frost, clouds, rain, or snow.

Methods by Which Air Reaches the Saturation Point 

If air reaches the saturation point while temperature and dew point are close together, it is highly 

likely that fog, low clouds, and precipitation will form. There are four methods by which air can 

reach the saturation point. First, when warm air moves over a cold surface, the air temperature 

drops and reaches the saturation point. Second, the saturation point may be reached when cold air 

and warm air mix. Third, when air cools at night through contact with the cooler ground, air reaches 

its saturation point. The fourth method occurs when air is lifted or is forced upward in the 

atmosphere.

Dew and Frost 

On cool, clear, calm nights, the temperature of the ground and objects on the surface can cause 

temperatures of the surrounding air to drop below the dew point. When this occurs, the moisture in 

the air condenses and deposits itself on the ground, buildings, and other objects like cars and 

aircraft. This moisture is known as dew and sometimes can be seen on grass and other objects in the 

morning. If the temperature is below freezing, the moisture is deposited in the form of frost. While 

dew poses no threat to a small UA, frost poses a definite flight safety hazard. Frost disrupts the flow 

of air over the wing and can drastically reduce the production of lift. It also increases drag, which 

when combined with lowered lift production, can adversely affect the ability to take off. A small UA

must be thoroughly cleaned and free of frost prior to beginning a flight. 

Clouds

To pilots, the cumulonimbus cloud is perhaps the most dangerous cloud type. It appears individually or 

in groups and is known as either an air mass or orographic thunderstorm. Heating of the air near the 

Earth’s surface creates an air mass thunderstorm; the upslope motion of air in the mountainous 

regions causes orographic thunderstorms. Cumulonimbus clouds that form in a continuous line are 

nonfrontal bands of thunderstorms or squall lines. 

Since rising air currents cause cumulonimbus clouds, they are extremely turbulent and pose a 

significant hazard to flight safety. For example, if a small UA enters a thunderstorm, the small UA could 

experience updrafts and downdrafts that exceed 3,000 fpm. In addition, thunderstorms can produce 

large hailstones, damaging lightning, tornadoes, and large quantities of water, all of which are 

potentially hazardous to an aircraft.

Standing Lenticular Altocumulus Clouds. 

Standing lenticular altocumulus clouds are formed on the crests of waves created by barriers in the 

wind flow. The clouds show little movement, hence the name standing. Wind, however, can be 

quite strong blowing through such clouds. They are characterized by their smooth, polished edges. 

The presence of these clouds is a good indication of very strong turbulence and should be avoided.
Chapter 3b: Effects of Weather on Small Unmanned Aircraft Performance

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 26

Stability

Stability of an air mass determines its typical weather characteristics. When one type of air mass

overlies another, conditions change with height. Characteristics typical of an unstable and a stable

air mass are as follows:

Unstable Air Stable Air

Cumuliform clouds Stratiform clouds and fog

Showery precipitation Continuous precipitation

Rough air (turbulence) Smooth air

Good visibility (except in blowing obstructions) Fair to poor visibility in haze and smoke

Fronts

As air masses move out of their source regions, they come in contact with other air masses of different 

properties. The zone between two different air masses is a frontal zone or front. Across this zone, 

temperature, humidity and wind often change rapidly over short distances.

Mountain Flying

When planning a flight over mountainous terrain, gather as much preflight information as possible on 

cloud reports, wind direction, wind speed, and stability of air. Satellites often help locate mountain 

waves. Adequate information may not always be available, so remain alert for signposts in the sky.

Wind at mountain top level in excess of 25 knots suggests some turbulence. Wind in excess of 40 knots 

across a mountain barrier dictates caution. Stratified clouds mean stable air. Standing lenticular and/or 

rotor clouds suggest a mountain wave; expect turbulence many miles to the lee of mountains and 

relative smooth flight on the windward side. Convective clouds on the windward side of mountains 

mean unstable air; expect turbulence in close proximity to and on either side of the mountain.

Structural Icing

Two conditions are necessary for structural icing in flight: 

1. The aircraft must be flying through visible water such as rain or cloud droplets

2. The temperature at the point where the moisture strikes the aircraft must be 0° C or colder. 

Aerodynamic cooling can lower temperature of an airfoil to 0° C even though the ambient temperature

is a few degrees warmer.

Thunderstorm Life Cycle

A thunderstorm cell during its life cycle progresses through three stages-( 1) the cumulus, (2) the 

mature, and (3) the dissipating. It is virtually impossible to visually detect the transition from one stage 

to another; the transition is subtle and by no means abrupt. Furthermore, a thunderstorm may be a 

cluster of cells in different stages of the lifecycle.

The Cumulus Stage

Although most cumulus clouds do not grow into thunderstorms, every thunderstorm begins as a

cumulus. The key feature of the cumulus stage is an updraft as illustrated in figure 3-4. The updraft 

varies in strength and extends from very near the surface to the cloud top. Growth rate of the cloud 
Chapter 3b: Effects of Weather on Small Unmanned Aircraft Performance

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 27

may exceed 3,000 feet per minute, so it is inadvisable to operate a small UA in an area of rapidly

building cumulus clouds. Early during the cumulus stage, water droplets are quite small but grow to 

raindrop size as the cloud grows. The upwelling air carries the liquid water above the freezing level 

creating an icing hazard. As the raindrops grow still heavier, they fall. The cold rain drags air with it 

creating a cold downdraft coexisting with the updraft; the cell has reached the mature stage.

The Mature Stage

Precipitation beginning to fall from the cloud base is your signal that a downdraft has developed and 

a cell has entered the mature stage. Cold rain in the downdraft retards compressional heating, and 

the downdraft remains cooler than surrounding air. Therefore, its downward speed is accelerated

and may exceed 2,500 feet per minute. The down rushing air spreads outward at the surface as

shown in figure 3-4 producing strong, gusty surface winds, a sharp temperature drop, and a rapid 

rise in pressure. The surface wind surge is a "plow wind" and its leading edge is the "first gust."

Meanwhile, updrafts reach a maximum with speeds possibly exceeding 6,000 feet per minute.

Updrafts and downdrafts in close proximity create strong vertical shear and a very turbulent 

environment. All thunderstorm hazards reach their greatest intensity during the mature stage.

The Dissipating Stage

Downdrafts characterize the dissipating stage of the thunderstorm cell as shown in figure 3-4 and 

the storm dies rapidly. When rain has ended and downdrafts have abated, the dissipating stage 'is 

complete. When all cells of the thunderstorm have completed this stage, only harmless cloud 

remnants remain.

Figure 3-4. Life cycle of a thunderstorm.
Chapter 3b: Effects of Weather on Small Unmanned Aircraft Performance

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 28

Ceiling 

For aviation purposes, a ceiling is the lowest layer of clouds reported as being broken or overcast, or 

the vertical visibility into an obscuration like fog or haze. Clouds are reported as broken when fiveeighths to seven-eighths of the sky is covered with clouds. Overcast means the entire sky is covered 

with clouds. Current ceiling information is reported by the aviation routine weather report (METAR) 

and automated weather stations of various types. 

Visibility 

Closely related to cloud cover and reported ceilings is visibility information. Visibility refers to the 

greatest horizontal distance at which prominent objects can be viewed with the naked eye. Current 

visibility is also reported in METAR and other aviation weather reports, as well as by automated 

weather systems. Visibility information, as predicted by meteorologists, is available for a pilot during a 

preflight weather briefing. 
Remote Pilot – Small Unmanned Aircraft Systems Study Guide 29

Chapter 4: 

Small Unmanned Aircraft Loading

Introduction

Before any flight, the remote pilot-in-command (PIC) should verify the aircraft is correctly loaded by 

determining the weight and balance condition of the aircraft. An aircraft’s weight and balance 

restrictions established by the manufacturer or the builder should be closely followed. Compliance 

with the manufacturer’s weight and balance limits is critical to flight safety. The remote PIC must 

consider the consequences of an overweight aircraft if an emergency condition arises.

• Although a maximum gross takeoff weight may be specified, the aircraft may not always

safely take off with this load under all conditions. Conditions that affect takeoff and climb

performance, such as high elevations, high air temperatures, and high humidity (high density

altitudes) may require a reduction in weight before flight is attempted. Other factors to

consider prior to takeoff are runway/launch area length, surface, slope, surface wind, and the

presence of obstacles. These factors may require a reduction in weight prior to flight. 

• Weight changes during flight also have a direct effect on aircraft performance. Fuel burn is

the most common weight change that takes place during flight. As fuel is used, the aircraft

becomes lighter and performance is improved, but this could have a negative effect on

balance. In small UA operations, weight change during flight may occur when expendable

items are used on board (e.g., a jettisonable load). 

Adverse balance conditions (i.e., weight distribution) may affect flight characteristics in much the same 

manner as those mentioned for an excess weight condition. Limits for the location of the center of 

gravity (CG) may be established by the manufacturer. The CG is not a fixed point marked on the 

aircraft; its location depends on the distribution of aircraft weight. As variable load items are shifted or 

expended, there may be a resultant shift in CG location. The remote PIC should determine how the CG 

will shift and the resultant effects on the aircraft. If the CG is not within the allowable limits after 

loading or do not remain within the allowable limits for safe flight, it will be necessary to relocate or 

shed some weight before flight is attempted.

Weight

Gravity is the pulling force that tends to draw all bodies to the center of the earth. The CG may be 

considered as a point at which all the weight of the aircraft is concentrated. If the aircraft were 

supported at its exact CG, it would balance in any attitude. It will be noted that CG is of major 

importance in a small UA, for its position has a great bearing upon stability. The allowable location of 

the CG is determined by the general design of each particular aircraft. The designers determine how far 

the center of pressure (CP) will travel. It is important to understand that an aircraft’s weight is 

concentrated at the CG and the aerodynamic forces of lift occur at the CP. When the CG is forward of 

the CP, there is a natural tendency for the aircraft to want to pitch nose down. If the CP is forward of 

the CG, a nose up pitching moment is created. Therefore, designers fix the aft limit of the CG forward 

of the CP for the corresponding flight speed in order to retain flight equilibrium. 

Weight has a definite relationship to lift. This relationship is simple, but important in understanding the 

aerodynamics of flying. Lift is the upward force on the wing acting perpendicular to the relative wind 

and perpendicular to the aircraft’s lateral axis. Lift is required to counteract the aircraft’s weight. In 
Chapter 4: Small Unmanned Aircraft Loading

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 30

stabilized level flight, when the lift force is equal to the weight force, the aircraft is in a state of 

equilibrium and neither accelerates upward or downward. If lift becomes less than weight, the vertical 

speed will decrease. When lift is greater than weight, the vertical speed will increase.

Stability

Stability is the inherent quality of an aircraft to correct for conditions that may disturb its equilibrium 

and to return to or to continue on the original flight path. It is primarily an aircraft design 

characteristic.

Stability in an aircraft affects two areas significantly: 

• Maneuverability—the quality of an aircraft that permits it to be maneuvered easily and to

withstand the stresses imposed by maneuvers. It is governed by the aircraft’s weight, inertia,

size and location of flight controls, structural strength, and powerplant. It too is an aircraft

design characteristic. 

• Controllability—the capability of an aircraft to respond to the pilot’s control, especially with

regard to flight path and attitude. It is the quality of the aircraft’s response to the pilot’s

control application when maneuvering the aircraft, regardless of its stability characteristics. 

Load Factors 

In aerodynamics, the maximum load factor (at given bank angle) is a proportion between lift and 

weight and has a trigonometric relationship. The load factor is measured in Gs (acceleration of gravity), 

a unit of force equal to the force exerted by gravity on a body at rest and indicates the force to which a 

body is subjected when it is accelerated. Any force applied to an aircraft to deflect its flight from a 

straight line produces a stress on its structure. The amount of this force is the load factor. While a 

course in aerodynamics is not a prerequisite for obtaining a remote pilot certificate, the competent 

pilot should have a solid understanding of the forces that act on the aircraft, the advantageous use of 

these forces, and the operating limitations of the aircraft being flown.

For example, a load factor of 3 means the total load on an aircraft’s structure is three times its weight. 

Since load factors are expressed in terms of Gs, a load factor of 3 may be spoken of as 3 Gs, or a load 

factor of 4 as 4 Gs.

With the structural design of aircraft planned to withstand only a certain amount of overload, a 

knowledge of load factors has become essential for all pilots. Load factors are important for two 

reasons:

1. It is possible for a pilot to impose a dangerous overload on the aircraft structures. 

2. An increased load factor increases the stalling speed and makes stalls possible at seemingly 

safe flight speeds. 
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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 31

Load Factors in Steep Turns 

At a constant altitude, during a coordinated 

turn in any aircraft, the load factor is the 

result of two forces: centrifugal force and 

weight. [Figure 4-1] For any given bank 

angle, the rate-of-turn varies with the 

airspeed—the higher the speed, the slower 

the rate-of-turn (ROT). This compensates for 

added centrifugal force, allowing the load 

factor to remain the same. 

Figure 4-2 reveals an important fact about 

turns—the load factor increases at a terrific 

rate after a bank has reached 45° or 50°. The 

load factor for any aircraft in a coordinated 

level turn at 60° bank is 2 Gs. The load factor 

in an 80° bank is 5.76 Gs. The wing must 

produce lift equal to these load factors if 

altitude is to be maintained. 

It should be noted how rapidly the line 

denoting load factor rises as it approaches 

the 90° bank line, which it never quite 

reaches because a 90° banked, constant 

altitude turn is not mathematically possible. 

An aircraft may be banked to 90° in a 

coordinated turn if not trying to hold 

altitude. An aircraft that can be held in a 90° 

banked slipping turn is capable of straight 

knife-edged flight. At slightly more than 80°, 

the load factor exceeds the limit of 6 Gs, the 

limit load factor of an acrobatic aircraft.

Load Factors and Stalling Speeds 

Any aircraft, within the limits of its structure, 

may be stalled at any airspeed. When a sufficiently high AOA is imposed, the smooth flow of air over 

an airfoil breaks up and separates, producing an abrupt change of flight characteristics and a sudden 

loss of lift, which results in a stall. 

A study of this effect has revealed that an aircraft’s stalling speed increases in proportion to the 

square root of the load factor. This means that an aircraft with a normal unaccelerated stalling 

speed of 50 knots can be stalled at 100 knots by inducing a load factor of 4 Gs. If it were possible for 

this aircraft to withstand a load factor of nine, it could be stalled at a speed of 150 knots. A pilot 

should be aware of the danger of inadvertently stalling the aircraft by increasing the load factor, as 

in a steep turn or spiral.

Figure 4-2. Angle of bank changes load factor in level flight.

Figure 4-1. Two forces cause load factor during turns.
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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 32

Figures 4-2 and 4-3 show that banking an aircraft greater than 72° in a steep turn produces a load 

factor of 3, and the stalling speed is increased significantly. If this turn is made in an aircraft with a 

normal unaccelerated stalling speed of 45 knots, the airspeed must be kept greater than 75 knots to 

prevent inducing a stall. A similar effect is experienced in a quick pull up or any maneuver producing 

load factors above 1 G. This sudden, unexpected loss of control, particularly in a steep turn or 

abrupt application of the back elevator control near the ground, has caused many accidents. 

Since the load factor is squared as the stalling speed doubles, tremendous loads may be imposed on 

structures by stalling an aircraft at relatively high airspeeds.

Figure 4-3. Load factor changes stall speed.

Weight and Balance 

Compliance with the weight and balance limits of any aircraft is critical to flight safety. Operating 

above the maximum weight limitation compromises the structural integrity of an aircraft and adversely 

affects its performance. Operation with the center of gravity (CG) outside the approved limits results in 

control difficulty. The aircraft’s weight and balance data is important information for a pilot that must 

be frequently reevaluated.

Weight Control

Weight is the force with which gravity attracts a body toward the center of the Earth. It is a product 

of the mass of a body and the acceleration acting on the body. Weight is a major factor in aircraft 

construction and operation and demands respect from all pilots. The force of gravity continuously 

attempts to pull an aircraft down toward Earth. The force of lift is the only force that counteracts 

weight and sustains an aircraft in flight. The amount of lift produced by an airfoil is limited by the 

airfoil design, AOA, airspeed, and air density. To assure that the lift generated is sufficient to 

counteract weight, loading an aircraft beyond the manufacturer’s recommended weight must be 

avoided. If the weight is greater than the lift generated, the aircraft may be incapable of flight.
Chapter 4: Small Unmanned Aircraft Loading

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 33

Effects of Weight 

Any item aboard an aircraft that increases the total weight is undesirable for performance. 

Manufacturers attempt to make an aircraft as light as possible without sacrificing strength or safety. 

The pilot should always be aware of the consequences of overloading. An overloaded aircraft may 

not be able to leave the ground, or if it does become airborne, it may exhibit unexpected and 

unusually poor flight characteristics. If not properly loaded, the initial indication of poor 

performance usually takes place during takeoff. 

Excessive weight reduces the flight performance in almost every respect. For example, the most 

important performance deficiencies of an overloaded aircraft are: 

• Higher takeoff speed

• Longer takeoff run

• Reduced rate and angle of climb

• Lower maximum altitude

• Shorter range

• Reduced cruising speed

• Reduced maneuverability

• Higher stalling speed

• Higher approach and landing speed

• Longer landing roll

The pilot must be knowledgeable about the effect of weight on the performance of the particular 

aircraft being flown. Excessive weight in itself reduces the safety margins available to the pilot and 

becomes even more hazardous when other performance-reducing factors are combined with excess 

weight. The pilot must also consider the consequences of an overweight aircraft if an emergency 

condition arises.
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Chapter 5:

Emergency Procedures

Introduction

An inflight emergency is usually an unexpected and unforeseen event that can have serious 

consequences for an unprepared remote pilot. During an emergency, a remote pilot is permitted to 

deviate from any part of 14 CFR part 107 to respond to the emergency. When a remote pilot does 

deviate from a rule due to an emergency, the remote will report the emergency if asked to do so by 

the FAA (also referred to as “the Administrator”).

Inflight Emergency

A remote pilot is responsible for the safe operation of the small UA at all times. A remote pilot must 

ensure that the aircraft is in a safe operating condition before flight, that there is not any hazard to 

persons or property, and that all required crew members are properly briefed on the operation and 

emergency procedures.

Before every flight, a remote pilot will conduct a preflight inspection of the aircraft. If any irregularities’ 

are found in the inspection, they must be corrected before the small UA is operated. Some small UA 

manufacturers will provide the remote pilot with preflight inspection items. For those small UAs that 

do not have a manufacturer checklist, the remote should develop a checklist that will provide enough 

information that the aircraft will be operated in a safe condition. 

When a remote pilot does experience an inflight emergency, the pilot may take any action to ensure 

that there is not a hazard to other people or property. For example, if during a flight the small UA 

experiences as battery fire, the remote pilot may need to climb the small UA above 400’ AGL to 

maneuver to a safe landing area. In this instance, a report will need to be made only if asked to do so 

by the FAA.

When other crew members are used during a flight, all of those crew members must be briefed on the 

flight and the planned emergency procedures for the flight. The briefing will be given to any visual 

observers (VO) that might be used and any non-certificated person who is allowed to manipulate the 

flight controls of the small UA.

For more information about emergencies, refer to 14 CFR part 107 and AC 107-2.
Determining the Performance of Small Unmanned Aircraft

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Chapter 6:

Crew Resource Management

For information on Crew Resource Management (CRM), refer to Chapter 10, “Aeronautical DecisionMaking and Judgment,” of this study guide.
6. Crew Resource Management

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 38

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Chapter 7:

Radio Communication Procedures

Introduction

Radio communications are an important aspect for the safe operation of aircraft in the NAS. It is 

through radio communications that pilots give and receive information before, during and at the 

conclusion of a flight. This information aids in the flow of aircraft in highly complex airspace areas as 

well as in less populated areas. Pilots can also send and receive important safety of flight issues such as 

unexpected weather conditions, and inflight emergencies. Although small UA pilots are not expected 

to communicate over radio frequencies, it is important for the UA pilot to understand “aviation 

language” and the different conversations they will encounter if the UA pilot is using a radio to aid 

them in situational awareness when operating in the NAS. Although much of the information provided 

here is geared toward manned aircraft pilots, the UA pilot needs to understand the unique way 

information is exchanged in the NAS.

Understanding Proper Radio Procedures 

Understanding proper radio phraseology and procedures 

contribute to a pilot’s ability to operate safely and 

efficiently in the airspace system. A review of the 

Pilot/Controller Glossary contained in the AIM assists a 

pilot in understanding standard radio terminology. The 

AIM also contains many examples of radio 

communications. 

ICAO has adopted a phonetic alphabet that should be used 

in radio communications. When communicating with ATC, 

pilots should use this alphabet to identify their aircraft. 

[Figure 7-1]

Traffic Advisory Practices at Airports without Operating 

Control Towers

Airport Operations without Operating Control Tower

There is no substitute for alertness while in the vicinity 

of an airport. It is essential that pilots be alert and look 

for other traffic a when operating at an airport without 

an operating control tower. This is of particular 

importance since other aircraft may not have 

communication capability or, in some cases, pilots may 

not communicate their presence or intentions when 

operating into or out of such airports. To achieve the 

greatest degree of safety, it is essential that all radioequipped aircraft transmit/receive on a common 

frequency and small UA pilots monitor other aircraft 

identified for the purpose of airport advisories.
7. Radio Communication Procedures

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 40

An airport may have a full or part-time tower or flight 

service station (FSS) located on the airport, a full or 

part-time universal communications (UNICOM) station or no aeronautical station at all. There are 

three ways for pilots to communicate their intention and obtain airport/traffic information when

operating at an airport that does not have an operating tower—by communicating with an FSS, a 

UNICOM operator, or by making a self-announce broadcast.

Many airports are now providing completely automated weather, radio check capability and airport

advisory information on an automated UNICOM system. These systems offer a variety of features,

typically selectable by microphone clicks, on the UNICOM frequency. Availability of the automated

UNICOM will be published in the Airport/Facility Directory and approach charts.

Understanding Communication on a Common Frequency

The key to communications at an airport without an operating control tower is selection of the

correct common frequency. The acronym CTAF, which stands for Common Traffic Advisory

Frequency, is synonymous with this program. A CTAF is a frequency designated for the purpose of

carrying out airport advisory practices while operating to or from an airport without an operating

control tower. The CTAF may be a UNICOM, MULTICOM, FSS, or tower frequency and is identified in 

appropriate aeronautical publications.

Communication/Broadcast Procedures

A MULTICOM frequency of 122.9 will be used at an airport that is non-towered and does not have a 

FSS or UNICOM.

Recommended Traffic Advisory Practices

Although a remote pilot-in-command is not required to communicate with manned aircraft when in 

the vicinity of a non-towered airport, safety in the National Airspace System requires that remote 

pilots are familiar with traffic patterns, radio procedures, and radio phraseology.

When a remote pilot plans to operate close to a non-towered airport, the first step in radio 

procedures is to identify the appropriate frequencies. Most non-towered airports will have a 

UNICOM frequency, which is usually 122.8; however, you should always check the Cart Supplements 

U.S. or sectional chart for the correct frequency. This frequency can vary when there are a large 

number of non-towered airports in the area. For non-towered airports that do not have a UNICOM 

or any other frequency listed, the MULTICOM frequency of 122.9 will be used. These frequencies 

can be found on a sectional chart by the airport or in the Chart Supplements publication from the 

FAA. 

When a manned aircraft is inbound to a non-towered airport, the standard operating practice is for 

the pilot to “broadcast in the blind” when 10 miles from the airport. This initial radio call will also 

include the position the aircraft is in relation to north, south, east or west from the airport. For 

example:

Town and Country traffic, Cessna 123 Bravo Foxtrot is 10 miles south inbound for landing, 

Town and Country traffic.

Figure 7-1. Phonetic Alphabet.
7. Radio Communication Procedures

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 41

When a manned aircraft is broadcasting at a non-towed airport, the aircraft should use the name of 

the airport of intended landing at the beginning of the broadcast, and again at the end of the 

broadcast. The reason for stating the name twice is to allow others who are on the frequency to 

confirm where the aircraft is going. The next broadcast that the manned aircraft should make is:

Town and Country traffic, Cessna 123 Bravo Foxtrot, is entering the pattern, mid-field left 

down-wind for runway 18, Town and Country traffic.

The aircraft is now entering the traffic pattern. In this example, the aircraft is making a standard 45 

degree entry to the downwind leg of the pattern for runway 18. Or, the aircraft could land straightin without entering the typical rectangular traffic pattern. Usually aircraft that are executing an 

instrument approach will use this method. Examples of a radio broadcast from aircraft that are 

using this technique are:

For an aircraft that is executing an instrument approach: 

Town and Country traffic, Cessna 123 Bravo Foxtrot, is one mile north of the airport, GPS 

runway 18, full stop landing, Town and Country traffic.

As the aircraft flies the traffic pattern for a landing, the following radio broadcasts should be made:

Town and Country traffic, Cessna 123 Bravo Foxtrot, left base, runway 18, Town and Country 

traffic.

Town and Country traffic, Cessna 123 Bravo Foxtrot, final, runway 18, Town and Country 

traffic.

After the aircraft has landed and is clear of the runway, the following broadcast should be made:

Town and Country traffic, Cessna 123 Bravo Foxtrot, is clear of runway 18, taxing to park, 

Town and Country traffic.

When an aircraft is departing a non-towered airport, the same procedures apply. For example, 

when the aircraft is ready for takeoff, the aircraft should make the following broadcast:

Town and Country traffic, Cessna 123 Bravo Foxtrot, departing runway 18, Town and Country 

traffic.

For safety reasons, a remote pilot must always scan the area where they are operating a small UA. 

This is especially important around an airport. While it is good operating procedures for manned 

aircraft to make radio broadcasts in the vicinity of a non-towered airport, by regulation, it is not 

mandatory. For this reason, a remote pilot must always look for other aircraft in the area, and use a 

radio for an extra layer of situational awareness. 

Aircraft Call Signs

When operating in the vicinity of any airport, either towered or non-towered, it is important for a 

remote pilot to understand radio communications of manned aircraft in the area. Although 14 CFR 

part 107 only requires the remote pilot to receive authorization to operate in certain airport areas, it 

can be a good operating practice to have a radio that will allow the remote pilot to monitor the 

appropriate frequencies in the area. The remote pilot should refrain from transmitting over any 

active aviation frequency unless there is an emergency situation. 
7. Radio Communication Procedures

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 42

Aviation has unique communication procedures that will be foreign to a remote pilot who has not 

been exposed to “aviation language” previously. One of those is aircraft call signs. All aircraft that 

are registered in the United States will have a unique registration number, or “N” number. For 

example, N123AB, which would be pronounced in aviation terms by use of the phonetic alphabet as, 

“November One-Two-Three-Alpha-Bravo.” In most cases, “November” will be replaced with either 

the aircraft manufacturer’s name (make) and in some cases, the type of aircraft (model). Usually, 

when the aircraft is a light general aviation (GA) aircraft, the manufacturer’s name will be used. In 

this case, if N123AB is a Cessna 172, the call sign would be “Cessna, One-Two-Three-Alpha-Bravo.” If 

the aircraft is a heavier GA aircraft, such as a turbo-prop, or turbo-jet, the aircraft’s model will be 

used in the call sign. If N123AB is a Cessna Citation, the call sign would be stated as, “Citation, OneTwo-Three-Alpha-Bravo.” Typically, airliners will use the name of their companies and their flight 

number in their call signs. For example, Southwest Airlines flight 711, would be said as, “SouthwestSeven-One-One.” There are a few airlines such as British Airways who will not use the company 

name in their call sign. For example, British Airways uses “Speedbird.” 

To close, a remote pilot is not expected to communicate with other aircraft in the vicinity of an 

airport, and should not do so unless there is an emergency situation. However, in the interest of 

safety in the NAS, it is important that a remote pilot understands the aviation language and the 

types of aircraft that can be operating in the same area as a small UA.
Remote Pilot – Small Unmanned Aircraft Systems Study Guide 43

Chapter 8:

Determining the Performance of Small Unmanned Aircraft

Introduction

The manufacturer may provide operational and performance information that contains the operational 

performance data for the aircraft such as data pertaining to takeoff, climb, range, endurance, descent, 

and landing. To be able to make practical use of the aircraft’s capabilities and limitations, it is essential 

to understand the significance of the operational data. The use of this data in flying operations is 

essential for safe and efficient operation. It should be emphasized that the manufacturers’ information 

regarding performance data is not standardized. If manufacturer-published performance data is 

unavailable, it is advisable to seek out performance data that may have already been determined and 

published by other users of the same small UA manufacturer model and use that data as a starting 

point.

Effect of Temperature on Density 

Increasing the temperature of a substance decreases its density. Conversely, decreasing the 

temperature increases the density. Thus, the density of air varies inversely with temperature. This 

statement is true only at a constant pressure. 

In the atmosphere, both temperature and pressure decrease with altitude and have conflicting effects 

upon density. However, a fairly rapid drop in pressure as altitude increases usually has a dominating 

effect. Hence, pilots can expect the density to decrease with altitude.

Effect of Humidity (Moisture) on Density 

The preceding paragraphs refer to air that is perfectly dry. In reality, it is never completely dry. The 

small amount of water vapor suspended in the atmosphere may be almost negligible under certain 

conditions, but in other conditions humidity may become an important factor in the performance of an 

aircraft. Water vapor is lighter than air; consequently, moist air is lighter than dry air. Therefore, as the 

water content of the air increases, the air becomes less dense, increasing density altitude and 

decreasing performance. It is lightest or least dense when, in a given set of conditions, it contains the 

maximum amount of water vapor. 

Humidity, also called relative humidity, refers to the amount of water vapor contained in the 

atmosphere and is expressed as a percentage of the maximum amount of water vapor the air can hold. 

This amount varies with temperature. Warm air holds more water vapor, while cold air holds less. 

Perfectly dry air that contains no water vapor has a relative humidity of zero percent, while saturated 

air, which cannot hold any more water vapor, has a relative humidity of 100 percent. Humidity alone is 

usually not considered an important factor in calculating density altitude and aircraft performance, but 

it is a contributing factor.
8. Determining the Performance of Small Unmanned Aircraft

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Chapter 9: 

Physiological Factors (Including Drugs and Alcohol) Affecting Pilot 

Performance

Introduction

14 CFR part 107 does not allow operation of small UA if the remote PIC, the person manipulating the 

controls, or Visual Observer (VO) is unable to safely carry out his or her responsibilities. It is the remote 

PIC’s responsibility to ensure all crewmembers are not participating in the operation while impaired. 

While drug and alcohol use are known to impair judgment, certain over-the-counter (OTC) medications 

and medical conditions could also affect the ability to safely operate a small UA. For example, certain 

antihistamines and decongestants may cause drowsiness. We also emphasize that part 107 prohibits a 

person from serving as a remote PIC, person manipulating the controls, VO, or other crewmember if he 

or she: 

• Has consumed any alcoholic beverage within the preceding 8 hours

• Is under the influence of alcohol

• Has a blood alcohol concentration of .04 percent or greater

• Is using a drug that affects the person’s mental or physical capabilities. 

There are certain medical conditions, such as epilepsy, may also create a risk to operations. It is the 

remote PIC’s responsibility to determine that their medical condition is under control and they can 

safely conduct a small UA operation.

Physiological/Medical Factors that Affect Pilot Performance

Important medical factors that a pilot should be aware of include the following:

• hyperventilation 

• stress

• fatigue

• dehydration

• heatstroke

• the effects of alcohol and drugs 

Hyperventilation 

Hyperventilation is the excessive rate and depth of respiration leading to abnormal loss of carbon 

dioxide from the blood. This condition occurs more often among pilots than is generally recognized. 

It seldom incapacitates completely, but it causes disturbing symptoms that can alarm the 

uninformed pilot. In such cases, increased breathing rate and anxiety further aggravate the 

problem. Hyperventilation can lead to unconsciousness due to the respiratory system’s overriding 

mechanism to regain control of breathing. Pilots encountering an unexpected stressful situation 

may subconsciously increase their breathing rate.

Common symptoms of hyperventilation include: 

• Visual impairment 

• Unconsciousness 

• Lightheaded or dizzy sensation 

• Tingling sensations 
Chapter 9: Physiological Factors (Including Drugs and Alcohol) Affecting Pilot Performance

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 46

• Hot and cold sensations 

• Muscle spasms 

The treatment for hyperventilation involves restoring the proper carbon dioxide level in the body. 

Breathing normally is both the best prevention and the best cure for hyperventilation. In addition to 

slowing the breathing rate, breathing into a paper bag or talking aloud helps to overcome 

hyperventilation. Recovery is usually rapid once the breathing rate is returned to normal.

Stress 

Stress is the body’s response to physical and psychological demands placed upon it. The body’s 

reaction to stress includes releasing chemical hormones (such as adrenaline) into the blood and 

increasing metabolism to provide more energy to the muscles. Blood sugar, heart rate, respiration, 

blood pressure, and perspiration all increase. The term “stressor” is used to describe an element 

that causes an individual to experience stress. Examples of stressors include physical stress (noise or 

vibration), physiological stress (fatigue), and psychological stress (difficult work or personal 

situations). 

Stress falls into two broad categories: acute (short term) and chronic (long term). Acute stress 

involves an immediate threat that is perceived as danger. This is the type of stress that triggers a 

“fight or flight” response in an individual, whether the threat is real or imagined. Normally, a healthy 

person can cope with acute stress and prevent stress overload. However, ongoing acute stress can 

develop into chronic stress. 

Chronic stress can be defined as a level of stress that presents an intolerable burden, exceeds the 

ability of an individual to cope, and causes individual performance to fall sharply. Unrelenting 

psychological pressures, such as loneliness, financial worries, and relationship or work problems can 

produce a cumulative level of stress that exceeds a person’s ability to cope with the situation. When 

stress reaches these levels, performance falls off rapidly. Pilots experiencing this level of stress are 

not safe and should not exercise their airman privileges. Pilots who suspect they are suffering from 

chronic stress should consult a physician.

Fatigue

Fatigue is frequently associated with pilot error. Some of the effects of fatigue include degradation 

of attention and concentration, impaired coordination, and decreased ability to communicate. 

These factors seriously influence the ability to make effective decisions. Physical fatigue results from 

sleep loss, exercise, or physical work. Factors such as stress and prolonged performance of cognitive 

work result in mental fatigue. 

Like stress, fatigue falls into two broad categories: acute and chronic. Acute fatigue is short term and 

is a normal occurrence in everyday living. It is the kind of tiredness people feel after a period of 

strenuous effort, excitement, or lack of sleep. Rest after exertion and 8 hours of sound sleep 

ordinarily cures this condition. 

A special type of acute fatigue is skill fatigue. This type of fatigue has two main effects on 

performance: 

• Timing disruption—appearing to perform a task as usual, but the timing of each component is

slightly off. This makes the pattern of the operation less smooth because the pilot performs

each component as though it were separate, instead of part of an integrated activity. 
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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 47

• Disruption of the perceptual field—concentrating attention upon movements or objects in

the center of vision and neglecting those in the periphery. This is accompanied by loss of

accuracy and smoothness in control movements. 

Acute fatigue has many causes, but the following are among the most important for the pilot: 

• Mild hypoxia (oxygen deficiency) 

• Physical stress 

• Psychological stress 

• Depletion of physical energy resulting from psychological stress 

• Sustained psychological stress 

Acute fatigue can be prevented by proper diet and adequate rest and sleep. A well-balanced diet 

prevents the body from needing to consume its own tissues as an energy source. Adequate rest 

maintains the body’s store of vital energy.

Chronic fatigue, extending over a long period of time, usually has psychological roots, although an 

underlying disease is sometimes responsible. Continuous high-stress levels produce chronic fatigue. 

Chronic fatigue is not relieved by proper diet and adequate rest and sleep and usually requires 

treatment by a physician. An individual may experience this condition in the form of weakness, 

tiredness, palpitations of the heart, breathlessness, headaches, or irritability. Sometimes chronic 

fatigue even creates stomach or intestinal problems and generalized aches and pains throughout 

the body. When the condition becomes serious enough, it leads to emotional illness. 

If suffering from acute fatigue, a remote pilot should not operate a small UA. If fatigue occurs during 

the operation of a small UA, no amount of training or experience can overcome the detrimental

effects. Getting adequate rest is the only way to prevent fatigue from occurring. Avoid flying a small 

UA without a full night’s rest, after working excessive hours, or after an especially exhausting or 

stressful day. Remote pilots who suspect they are suffering from chronic fatigue should consult a 

physician.

Dehydration 

Dehydration is the term given to a critical loss of water from the body. Causes of dehydration are 

hot temperatures, wind, humidity, and diuretic drinks—coffee, tea, alcohol, and caffeinated soft 

drinks. Some common signs of dehydration are headache, fatigue, cramps, sleepiness, and dizziness. 

The first noticeable effect of dehydration is fatigue, which in turn makes top physical and mental 

performance difficult, if not impossible. Flying a small UA for long periods in hot summer 

temperatures or at high altitudes increases the susceptibility to dehydration because these 

conditions tend to increase the rate of water loss from the body. 

To help prevent dehydration, drink two to four quarts of water every 24 hours. Since each person is 

physiologically different, this is only a guide. Most people are aware of the eight-glasses-a-day 

guide: If each glass of water is eight ounces, this equates to 64 ounces, which is two quarts. If this 

fluid is not replaced, fatigue progresses to dizziness, weakness, nausea, tingling of hands and feet, 

abdominal cramps, and extreme thirst. 

The key for pilots is to be continually aware of their condition. Most people become thirsty with a 

1.5 quart deficit or a loss of 2 percent of total body weight. This level of dehydration triggers the 

“thirst mechanism.” The problem is that the thirst mechanism arrives too late and is turned off too 
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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 48

easily. A small amount of fluid in the mouth turns this mechanism off and the replacement of 

needed body fluid is delayed. 

Other steps to prevent dehydration include: 

• Carrying a container in order to measure daily water intake. 

• Staying ahead—not relying on the thirst sensation as an alarm. If plain water is not preferred,

add some sport drink flavoring to make it more acceptable. 

• Limiting daily intake of caffeine and alcohol (both are diuretics and stimulate increased

production of urine). 

Heatstroke

Heatstroke is a condition caused by any inability of the body to control its temperature. Onset of 

this condition may be recognized by the symptoms of dehydration, but also has been known to be 

recognized only upon complete collapse.

To prevent these symptoms, it is recommended that an ample supply of water be carried and used 

at frequent intervals, whether thirsty or not. The body normally absorbs water at a rate of 1.2 to 1.5 

quarts per hour. Individuals should drink one quart per hour for severe heat stress conditions or one 

pint per hour for moderate stress conditions. For more information on water consumption, refer to 

the “Dehydration” section of this chapter.

Drugs

The Federal Aviation Regulations include no specific references to medication usage. Title 14 of the 

CFR prohibits acting as PIC or in any other capacity as a required pilot flight crewmember, while that 

person:

1. Knows or has reason to know of any medical condition that would make the person unable to 

meet the requirement for the medical certificate necessary for the pilot operation, or 

2. Is taking medication or receiving other treatment for a medical condition that results in the 

person being unable to meet the requirements for the medical certificate necessary for the 

pilot operation. 

Further, 14 CFR part 107 and 14 CFR part 91, sections 91.17 and 91.19 prohibit the use of any drug 

that affects the person’s faculties in any way contrary to safety. 

There are several thousand medications currently approved by the U.S. Food and Drug 

Administration (FDA), not including OTC drugs. Virtually all medications have the potential for 

adverse side effects in some people. Additionally, herbal and dietary supplements, sport and energy 

boosters, and some other “natural” products are derived from substances often found in 

medications that could also have adverse side effects. While some individuals experience no side 

effects with a particular drug or product, others may be noticeably affected. The FAA regularly 

reviews FDA and other data to assure that medications found acceptable for aviation duties do not 

pose an adverse safety risk. 

Some of the most commonly used OTC drugs, antihistamines and decongestants, have the potential 

to cause noticeable adverse side effects, including drowsiness and cognitive deficits. The symptoms 

associated with common upper respiratory infections, including the common cold, often suppress a 

pilot’s desire to fly, and treating symptoms with a drug that causes adverse side effects only 

compounds the problem. Particularly, medications containing diphenhydramine (e.g., Benadryl) are 
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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 49

known to cause drowsiness and have a prolonged half-life, meaning the drugs stay in one’s system 

for an extended time, which lengthens the time that side effects are present. 

Prior to each and every flight, all pilots must do a proper physical self-assessment to ensure safety. 

A great mnemonic is IMSAFE, which stands for Illness, Medication, Stress, Alcohol, Fatigue, and 

Emotion. 

For the medication component of IMSAFE, pilots need to ask themselves, “Am I taking any 

medicines that might affect my judgment or make me drowsy? For any new medication, OTC or 

prescribed, you should wait at least 48 hours after the first dose before flying to determine you do 

not have any adverse side effects that would make it unsafe to operate an aircraft. In addition to 

medication questions, pilots should also consider the following:

• Do not take any unnecessary or elective medications.

• Make sure you eat regular balanced meals.

• Bring a snack.

• Maintain good hydration - bring plenty of water.

• Ensure adequate sleep the night prior to the flight.

• Stay physically fit.

Alcohol

Alcohol impairs the efficiency of the human body. 

[Figure 9-1] Studies have shown that consuming 

alcohol is closely linked to performance deterioration. 

Pilots must make hundreds of decisions, some of them 

time-critical, during the course of a flight. The safe 

outcome of any flight depends on the ability to make 

the correct decisions and take the appropriate actions 

during routine occurrences, as well as abnormal 

situations. The influence of alcohol drastically reduces 

the chances of completing a flight without incident. 

Even in small amounts, alcohol can impair judgment, 

decrease sense of responsibility, affect coordination, 

constrict visual field, diminish memory, reduce 

reasoning ability, and lower attention span. As little as 

one ounce of alcohol can decrease the speed and 

strength of muscular reflexes, lessen the efficiency of 

eye movements while reading, and increase the 

frequency at which errors are committed. 

Impairments in vision and hearing can occur from 

consuming as little as one drink. 

While experiencing a hangover, a pilot is still under 

the influence of alcohol. Although a pilot may think he 

or she is functioning normally, motor and mental 

response impairment is still present. Considerable 

amounts of alcohol can remain in the body for over 16 

hours, so pilots should be cautious about flying too soon after drinking.

Figure 9-1. Impairment scale with alcohol use.
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Intoxication is determined by the amount of alcohol in the bloodstream. This is usually measured as 

a percentage by weight in the blood. 14 CFR part 91 requires that blood alcohol level be less than 

.04 percent and that 8 hours pass between drinking alcohol and piloting an aircraft. A pilot with a 

blood alcohol level of .04 percent or greater after 8 hours cannot fly until the blood alcohol falls 

below that amount. Even though blood alcohol may be well below .04 percent, a pilot cannot fly 

sooner than 8 hours after drinking alcohol. Although the regulations are quite specific, it is a good 

idea to be more conservative than the regulations. 

Vision and Flight 

The more a pilot understands about the eyes and how they function, the easier it is to use vision 

effectively and compensate for potential problems.

Scanning Techniques 

To scan effectively, pilots must look from right to left or left to right. They should begin scanning at 

the greatest distance an object can be perceived (top) and move inward toward the position of the 

aircraft (bottom). For each stop, an area approximately 30° wide should be scanned. The duration of 

each stop is based on the degree of detail that is required, but no stop should last longer than 2 to 3 

seconds. When moving from one viewing point to the next, pilots should overlap the previous field 

of view by 10°. [Figure 9-2]

Figure 9-2. Scanning techniques.
Remote Pilot – Small Unmanned Aircraft Systems Study Guide 51

Chapter 10:

Aeronautical Decision-Making and Judgment

Introduction

Aeronautical decision-making (ADM) is decision-making in a unique environment—aviation. It is a 

systematic approach to the mental process used by pilots to consistently determine the best course of 

action in response to a given set of circumstances. It is what a pilot intends to do based on the latest 

information he or she has. 

The importance of learning and understanding effective ADM skills cannot be overemphasized. While 

progress is continually being made in the advancement of pilot training methods, aircraft equipment 

and systems, and services for pilots, accidents still occur. Despite all the changes in technology to 

improve flight safety, one factor remains the same: the human factor which leads to errors. It is 

estimated that approximately 80 percent of all aviation accidents are related to human factors and the 

vast majority of these accidents occur during landing (24.1 percent) and takeoff (23.4 percent).

ADM is a systematic approach to risk assessment and stress management. To understand ADM is to 

also understand how personal attitudes can influence decision-making and how those attitudes can be 

modified to enhance safety in the operation of a small UA. It is important to understand the factors 

that cause humans to make decisions and how the decision-making process not only works, but can be 

improved. 

History of ADM 

For over 25 years, the importance of good pilot judgment, or aeronautical decision-making (ADM), has 

been recognized as critical to the safe operation of aircraft, as well as accident avoidance. The airline 

industry, motivated by the need to reduce accidents caused by human factors, developed the first 

training programs based on improving ADM. Crew resource management (CRM) training for flight 

crews is focused on the effective use of all available resources: human resources, hardware, and 

information supporting ADM to facilitate crew cooperation and improve decision-making. The goal of 

all flight crews is good ADM and the use of CRM is one way to make good decisions. 

Research in this area prompted the Federal Aviation Administration (FAA) to produce training directed 

at improving the decision-making of pilots and led to current FAA regulations that require that 

decision-making be taught as part of the pilot training curriculum. Aeronautical Decision Making and 

Risk Management are topics that the FAA is required to test an applicant about for the issuance of an 

sUAS certificate. ADM research, development, and testing culminated in 1987 with the publication of 

six manuals oriented to the decision-making needs of variously rated pilots. These manuals provided 

multifaceted materials designed to reduce the number of decision-related accidents. The effectiveness 

of these materials was validated in independent studies where student pilots received such training in 

conjunction with the standard flying curriculum. When tested, the pilots who had received ADMtraining made fewer inflight errors than those who had not received ADM training. The differences 

were statistically significant and ranged from about 10 to 50 percent fewer judgment errors. In the 

operational environment, an operator flying about 400,000 hours annually demonstrated a 54 percent 

reduction in accident rate after using these materials for recurrency training. 
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Contrary to popular opinion, good judgment can be taught. Tradition held that good judgment was a 

natural by-product of experience, but as pilots continued to log accident-free flight hours, a 

corresponding increase of good judgment was assumed. Building upon the foundation of conventional 

decision-making, ADM enhances the process to decrease the probability of human error and increase 

the probability of a safe flight. ADM provides a structured, systematic approach to analyzing changes 

that occur during a flight and how these changes might affect the safe outcome of a flight. The ADM 

process addresses all aspects of decision-making and identifies the steps involved in good decisionmaking. 

Steps for good decision-making are: 

1. Identifying personal attitudes hazardous to safe flight.

2. Learning behavior modification techniques.

3. Learning how to recognize and cope with stress.

4. Developing risk assessment skills.

5. Using all resources.

6. Evaluating the effectiveness of one’s ADM skills.

Risk Management

The goal of risk management is to proactively identify 

safety-related hazards and mitigate the associated 

risks. Risk management is an important component of 

ADM. When a pilot follows good decision-making 

practices, the inherent risk in a flight is reduced or even 

eliminated. The ability to make good decisions is based 

upon direct or indirect experience and education. The 

formal risk management decision-making process 

involves six steps as shown in Figure 10-1. 

Consider automotive seat belt use. In just two decades, 

seat belt use has become the norm, placing those who 

do not wear seat belts outside the norm, but this group 

may learn to wear a seat belt by either direct or 

indirect experience. For example, a driver learns 

through direct experience about the value of wearing a 

seat belt when he or she is involved in a car accident 

that leads to a personal injury. An indirect learning 

experience occurs when a loved one is injured during a 

car accident because he or she failed to wear a seat 

belt. 

As you work through the ADM cycle, it is important to remember the four fundamental principles of 

risk management.

1. Accept no unnecessary risk. Flying is not possible without risk, but unnecessary risk comes 

without a corresponding return. 

2. Make risk decisions at the appropriate level. Risk decisions should be made by the person 

who can develop and implement risk controls.

3. Accept risk when benefits outweigh dangers (costs). 

Figure 10-1. Risk management decision-making process.
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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 53

4. Integrate risk management into planning at all levels. Because risk is an unavoidable part of 

every flight, safety requires the use of appropriate and effective risk management not just in 

the preflight planning stage, but in all stages of the flight. 

While poor decision-making in everyday life does not always lead to tragedy, the margin for error in

aviation is thin. Since ADM enhances management of an aeronautical environment, all pilots should 

become familiar with and employ ADM.

Crew Resource Management (CRM) and Single-Pilot Resource Management 

While CRM focuses on pilots operating in crew environments, many of the concepts apply to singlepilot operations. Many CRM principles have been successfully applied to single-pilot aircraft and led to 

the development of Single-Pilot Resource Management (SRM). SRM is defined as the art and science of 

managing all the resources available to a single pilot (prior to and during flight) to ensure the 

successful outcome of the flight. SRM includes the concepts of ADM, risk management (RM), task 

management (TM), automation management (AM), controlled flight into terrain (CFIT) awareness, and 

situational awareness (SA). SRM training helps the pilot maintain situational awareness by managing 

the automation and associated aircraft control and navigation tasks. This enables the pilot to 

accurately assess and manage risk and make accurate and timely decisions. 

SRM is all about helping pilots learn how to gather information, analyze it, and make decisions.

Hazard and Risk 

Two defining elements of ADM are hazard and risk. Hazard is a real or perceived condition, event, or 

circumstance that a pilot encounters. When faced with a hazard, the pilot makes an assessment of that 

hazard based upon various factors. The pilot assigns a value to the potential impact of the hazard, 

which qualifies the pilot’s assessment of the hazard—risk.

Therefore, risk is an assessment of the single or cumulative hazard facing a pilot; however, different 

pilots see hazards differently.

Hazardous Attitudes and Antidotes 

Being fit to fly depends on more than just a pilot’s physical condition and recent experience. For 

example, attitude affects the quality of decisions. Attitude is a motivational predisposition to 

respond to people, situations, or events in a given manner. Studies have identified five hazardous 

attitudes that can interfere with the ability to make sound decisions and exercise authority properly: 

anti-authority, impulsivity, invulnerability, macho, and resignation. [Figure 10-2] 

Hazardous attitudes contribute to poor pilot judgment but can be effectively counteracted by 

redirecting the hazardous attitude so that correct action can be taken. Recognition of hazardous 

thoughts is the first step toward neutralizing them. After recognizing a thought as hazardous, the 

pilot should label it as hazardous, then state the corresponding antidote. Antidotes should be 

memorized for each of the hazardous attitudes so they automatically come to mind when needed.
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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 54

Figure 10-2. The five hazardous attitudes identified through past and contemporary study.

Risk

During each flight, the single pilot makes many decisions under hazardous conditions. To fly safely, 

the pilot needs to assess the degree of risk and determine the best course of action to mitigate the 

risk. 

Assessing Risk 

For the single pilot, assessing risk is not as simple as it sounds. For example, the pilot acts as his or 

her own quality control in making decisions. If a fatigued pilot who has flown 16 hours is asked if 

he or she is too tired to continue flying, the answer may be “no.” Most pilots are goal oriented 

and when asked to accept a flight, there is a tendency to deny personal limitations while adding 

weight to issues not germane to the mission. For example, pilots of helicopter emergency 

services (EMS) have been known (more than other groups) to make flight decisions that add 

significant weight to the patient’s welfare. These pilots add weight to intangible factors (the 

patient in this case) and fail to appropriately quantify actual hazards, such as fatigue or weather, 

when making flight decisions. The single pilot who has no other crew member for consultation 

must wrestle with the intangible factors that draw one into a hazardous position. Therefore, he 

or she has a greater vulnerability than a full crew. 
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Mitigating Risk 

Risk assessment is only part of the equation.

One of the best ways single pilots can mitigate risk is to use the IMSAFE checklist to determine 

physical and mental readiness for flying: 

1. Illness—Am I sick? Illness is an obvious pilot risk. 

2. Medication—Am I taking any medicines that might affect my judgment or make me drowsy? 

3. Stress—Am I under psychological pressure from the job? Do I have money, health, or family 

problems? Stress causes concentration and performance problems. While the regulations list 

medical conditions that require grounding, stress is not among them. The pilot should 

consider the effects of stress on performance. 

4. Alcohol—Have I been drinking within 8 hours? Within 24 hours? As little as one ounce of 

liquor, one bottle of beer, or four ounces of wine can impair flying skills. Alcohol also renders 

a pilot more susceptible to disorientation and hypoxia. 

5. Fatigue—Am I tired and not adequately rested? Fatigue continues to be one of the most 

insidious hazards to flight safety, as it may not be apparent to a pilot until serious errors are 

made. 

6. Emotion—Am I emotionally upset? 

The PAVE Checklist 

Another way to mitigate risk is to perceive hazards. By incorporating the PAVE checklist into 

preflight planning, the pilot divides the risks of flight into four categories: Pilot-in-command (PIC), 

Aircraft, enVironment, and External pressures (PAVE) which form part of a pilot’s decision-making 

process. 

With the PAVE checklist, pilots have a simple way to remember each category to examine for risk 

prior to each flight. 

Once a pilot identifies the risks of a flight, he or she needs to decide whether the risk, or 

combination of risks, can be managed safely and successfully. If not, make the decision to cancel the 

flight. If the pilot decides to continue with the flight, he or she should develop strategies to mitigate 

the risks. One way a pilot can control the risks is to set personal minimums for items in each risk 

category. These are limits unique to that individual pilot’s current level of experience and 

proficiency.

P = Pilot-in-Command (PIC) 

The pilot is one of the risk factors in a flight. The pilot must ask, “Am I ready for this flight?” in 

terms of experience, recency, currency, physical, and emotional condition. The IMSAFE checklist 

provides the answers. 

A = Aircraft

What limitations will the aircraft impose upon the trip? Ask the following questions: 

• Is this the right aircraft for the flight? 

• Am I familiar with and current in this aircraft? 

• Can this aircraft carry the planned load? 
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V = EnVironment 

Weather 

Weather is a major environmental consideration. Earlier it was suggested pilots set their own 

personal minimums, especially when it comes to weather. As pilots evaluate the weather for a 

particular flight, they should consider the following: 

• What is the current ceiling and visibility? 

• Consider the possibility that the weather may be different than forecast. 

• Are there any thunderstorms present or forecast? 

• If there are clouds, is there any icing, current or forecast? What is the temperature/dew point

spread and the current temperature at altitude?

Terrain

Evaluation of terrain is another important component of analyzing the flight environment.

Airspace 

Check the airspace and any temporary flight restriction (TFRs). 

E = External Pressures 

External pressures are influences external to the flight that create a sense of pressure to 

complete a flight—often at the expense of safety. Factors that can be external pressures include 

the following:

• The desire to demonstrate pilot qualifications 

• The desire to impress someone (Probably the two most dangerous words in aviation are

“Watch this!”) 

• The pilot’s general goal-completion orientation 

• Emotional pressure associated with acknowledging that skill and experience levels may be

lower than a pilot would like them to be. Pride can be a powerful external factor!

Managing External Pressures 

Management of external pressure is the single most important key to risk management because 

it is the one risk factor category that can cause a pilot to ignore all the other risk factors.

The use of personal standard operating procedures (SOPs) is one way to manage external 

pressures. The goal is to supply a release for the external pressures of a flight.

Human Factors 

Why are human conditions, such as fatigue, complacency and stress, so important in aviation? These 

conditions, along with many others, are called human factors. Human factors directly cause or 

contribute to many aviation accidents and have been documented as a primary contributor to more 

than 70 percent of aircraft accidents. 

Typically, human factor incidents/accidents are associated with flight operations but recently have also 

become a major concern in aviation maintenance and air traffic management as well. Over the past 

several years, the FAA has made the study and research of human factors a top priority by working 

closely with engineers, pilots, mechanics, and ATC to apply the latest knowledge about human factors 

in an effort to help operators and maintainers improve safety and efficiency in their daily operations. 
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Human factors science, or human factors technologies, is a multidisciplinary field incorporating 

contributions from psychology, engineering, industrial design, statistics, operations research, and 

anthropometry. It is a term that covers the science of understanding the properties of human 

capability, the application of this understanding to the design, development and deployment of 

systems and services, and the art of ensuring successful application of human factor principles into all 

aspects of aviation to include pilots, ATC, and aviation maintenance. Human factors is often considered 

synonymous with CRM or maintenance resource management (MRM) but is really much broader in 

both its knowledge base and scope. Human factors involves gathering research specific to certain 

situations (i.e., flight, maintenance, stress levels, knowledge) about human abilities, limitations, and 

other characteristics and applying it to tool design, machines, systems, tasks, jobs, and environments 

to produce safe, comfortable, and effective human use. The entire aviation community benefits greatly 

from human factors research and development as it helps better understand how humans can most 

safely and efficiently perform their jobs and improve the tools and systems in which they interact. 

The Decision-Making Process 

An understanding of the decision-making process provides the pilot with a foundation for developing 

ADM and SRM skills. While some situations, such as engine failure, require an immediate pilot 

response using established procedures, there is usually time during a flight to analyze any changes that 

occur, gather information, and assess risks before reaching a decision. 

Risk management and risk intervention is much more than the simple definitions of the terms might 

suggest. Risk management and risk intervention are decision-making processes designed to 

systematically identify hazards, assess the degree of risk, and determine the best course of action. 

These processes involve the identification of hazards, followed by assessments of the risks, analysis of 

the controls, making control decisions, using the controls, and monitoring the results.

The steps leading to this decision constitute a decision-making process. Three models of a structured 

framework for problem-solving and decision-making are the 5P, the 3P using PAVE, CARE and TEAM, 

and the DECIDE models. They provide assistance in organizing the decision process. All these models 

have been identified as helpful to the single pilot in organizing critical decisions.

Single-Pilot Resource Management (SRM) 

Single-Pilot Resource Management (SRM) is about how to gather information, analyze it, and make 

decisions. Learning how to identify problems, analyze the information, and make informed and 

timely decisions is not as straightforward as the training involved in learning specific maneuvers. 

Learning how to judge a situation and “how to think” in the endless variety of situations 

encountered while flying out in the “real world” is more difficult. 

There is no one right answer in ADM, rather each pilot is expected to analyze each situation in light 

of experience level, personal minimums, and current physical and mental readiness level, and make 

his or her own decision.

Perceive, Process, Perform (3P) Model 

The Perceive, Process, Perform (3P) model for ADM offers a simple, practical, and systematic 

approach that can be used during all phases of flight. To use it, the pilot will: 

• Perceive the given set of circumstances for a flight 

• Process by evaluating their impact on flight safety 

• Perform by implementing the best course of action 
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Use the Perceive, Process, Perform, and Evaluate method as a continuous model for every 

aeronautical decision that you make. Although human beings will inevitably make mistakes, 

anything that you can do to recognize and minimize potential threats to your safety will make you a 

better pilot. 

Depending upon the nature of the activity and the time available, risk management processing can 

take place in any of three timeframes. [Figure 10-3] Most flight training activities take place in the 

“time-critical” timeframe for risk management. The six steps of risk management can be combined 

into an easy-to-remember 3P model for practical risk management: Perceive, Process, Perform with 

the PAVE, CARE and TEAM checklists. Pilots can help perceive hazards by using the PAVE checklist 

of: Pilot, Aircraft, enVironment, and External pressures. They can process hazards by using the CARE 

checklist of: Consequences, Alternatives, Reality, External factors. Finally, pilots can perform risk 

management by using the TEAM choice list of: Transfer, Eliminate, Accept, or Mitigate. 

Figure 10-3. Risk management processing can take place in any of three timeframes.

PAVE Checklist: Identify Hazards and Personal Minimums 

In the first step, the goal is to develop situational awareness by perceiving hazards, which are 

present events, objects, or circumstances that could contribute to an undesired future event. In 

this step, the pilot will systematically identify and list hazards associated with all aspects of the 

flight: Pilot, Aircraft, enVironment, and External pressures, which makes up the PAVE checklist. 

[Figure 10-4] All four elements combine and interact to create a unique situation for any flight. 

Pay special attention to the pilot-aircraft combination, and consider whether the combined 

“pilot-aircraft team” is capable of the mission you want to fly. For example, you may be a very 

experienced and proficient pilot, but your weather flying ability is still limited if you are flying an 

unfamiliar aircraft. On the other hand, you may have a new technically advanced aircraft that you 

have flown for a considerable amount of time.

Figure 10-4. A real-world example of how the 3P model guides decisions on a cross-country trip using the PAVE checklist.
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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 59

Decision-Making in a Dynamic Environment 

A solid approach to decision-making is through the use of analytical models, such as the 5 Ps, 3P, and 

DECIDE. Good decisions result when pilots gather all available information, review it, analyze the 

options, rate the options, select a course of action, and evaluate that course of action for correctness. 

In some situations, there is not always time to make decisions based on analytical decision-making 

skills. A good example is a quarterback whose actions are based upon a highly fluid and changing 

situation. He intends to execute a plan, but new circumstances dictate decision-making on the fly. This 

type of decision-making is called automatic decision-making or naturalized decision-making. 

[Figure 10-5B]
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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 60

Figure 10-5. The DECIDE model has been recognized worldwide. Its application is illustrated in column A while automatic/naturalistic 

decision-making is shown in column B.

Automatic Decision-Making

For the past several decades, research into how people actually make decisions has revealed that 

when pressed for time, experts faced with a task loaded with uncertainty first assess whether the 

situation strikes them as familiar. Rather than comparing the pros and cons of different approaches, 

they quickly imagine how one or a few possible courses of action in such situations will play out. 
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Experts take the first workable option they can find. While it may not be the best of all possible 

choices, it often yields remarkably good results. 

The terms “naturalistic” and “automatic decision-making” have been coined to describe this type of 

decision-making. The ability to make automatic decisions holds true for a range of experts from 

firefighters to chess players. It appears the expert’s ability hinges on the recognition of patterns and 

consistencies that clarify options in complex situations. Experts appear to make provisional sense of 

a situation, without actually reaching a decision, by launching experience-based actions that in turn 

trigger creative revisions. 

This is a reflexive type of decision-making anchored in training and experience and is most often 

used in times of emergencies when there is no time to practice analytical decision-making. 

Naturalistic or automatic decision-making improves with training and experience, and a pilot will 

find himself or herself using a combination of decision-making tools that correlate with individual 

experience and training. 

Operational Pitfalls 

Although more experienced pilots are likely to make more automatic decisions, there are 

tendencies or operational pitfalls that come with the development of pilot experience. These are 

classic behavioral traps into which pilots have been known to fall. More experienced pilots, as a 

rule, try to complete a flight as planned. The desire to meet these goals can have an adverse 

effect on safety and contribute to an unrealistic assessment of piloting skills. These dangerous 

tendencies or behavior patterns, which must be identified and eliminated, include the 

operational pitfalls shown in Figure 10-6. 
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Figure 10-6. Typical operational pitfalls requiring pilot awareness.

Stress Management 

Everyone is stressed to some degree almost all of the time. A certain amount of stress is good since 

it keeps a person alert and prevents complacency. Effects of stress are cumulative and, if the pilot 

does not cope with them in an appropriate way, they can eventually add up to an intolerable 

burden. Performance generally increases with the onset of stress, peaks, and then begins to fall off 

rapidly as stress levels exceed a person’s ability to cope. The ability to make effective decisions 

during flight can be impaired by stress. There are two categories of stress—acute and chronic. These 

are both explained in Chapter 9, “Physiological Factors (Including Drugs and Alcohol) Affecting Pilot 

Performance,” of this study guide.

There are several techniques to help manage the accumulation of life stresses and prevent stress 

overload. For example, to help reduce stress levels, set aside time for relaxation each day or 

maintain a program of physical fitness. To prevent stress overload, learn to manage time more 

effectively to avoid pressures imposed by getting behind schedule and not meeting deadlines. 
Chapter 10: Aeronautical Decision-Making and Judgment

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 63

Use of Resources 

To make informed decisions during flight operations, a pilot must also become aware of the 

available resources. Since useful tools and sources of information may not always be readily 

apparent, learning to recognize these resources is an essential part of ADM training. Resources must 

not only be identified, but a pilot must also develop the skills to evaluate whether there is time to 

use a particular resource and the impact its use will have upon the safety of flight.

Figure 10-7. System stressors. Environmental, physiological, and psychological stress are factors that affect decision-making skills. 

These stressors have a profound impact especially during periods of high workload.

Situational Awareness

Situational awareness is the accurate perception and understanding of all the factors and conditions 

within the five fundamental risk elements (flight, pilot, aircraft, environment, and type of operation 

that comprise any given aviation situation) that affect safety before, during, and after the flight. 

Maintaining situational awareness requires an understanding of the relative significance of all flight 

related factors and their future impact on the flight. When a pilot understands what is going on and 

has an overview of the total operation, he or she is not fixated on one perceived significant factor. Not 

only is it important for a pilot to know the aircraft’s geographical location, it is also important he or she 

understand what is happening.

Obstacles to Maintaining Situational Awareness 

Fatigue, stress, and work overload can cause a pilot to fixate on a single perceived important item 

and reduce an overall situational awareness of the flight. A contributing factor in many accidents is a 

distraction that diverts the pilot’s attention from monitoring the aircraft.

Workload Management 

Effective workload management ensures essential operations are accomplished by planning, 

prioritizing, and sequencing tasks to avoid work overload. As experience is gained, a pilot learns 

to recognize future workload requirements and can prepare for high workload periods during 

times of low workload.

In addition, a pilot should listen to ATIS, Automated Surface Observing System (ASOS), or 

Automated Weather Observing System (AWOS), if available, and then monitor the tower 

frequency or Common Traffic Advisory Frequency (CTAF) to get a good idea of what traffic 

conditions to expect.
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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 64

Recognizing a work overload situation is also an important component of managing workload. 

The first effect of high workload is that the pilot may be working harder but accomplishing less. 

As workload increases, attention cannot be devoted to several tasks at one time, and the pilot 

may begin to focus on one item. When a pilot becomes task saturated, there is no awareness of 

input from various sources, so decisions may be made on incomplete information and the 

possibility of error increases. 

When a work overload situation exists, a pilot needs to stop, think, slow down, and prioritize. It is 

important to understand how to decrease workload.
Remote Pilot – Small Unmanned Aircraft Systems Study Guide 65

Chapter 11: 

Airport Operations

Introduction

The definition for airports refers to any area of land or water used or intended for landing or takeoff of 

aircraft. This includes, within the five categories of airports listed below, special types of facilities 

including seaplane bases, heliports, and facilities to accommodate tilt rotor aircraft. An airport includes 

an area used or intended for airport buildings, facilities, as well as rights of way together with the 

buildings and facilities.

Types of Airports 

There are two types of airports—towered and non-towered. These types can be further subdivided to: 

• Civil Airports—airports that are open to the general public. 

• Military/Federal Government airports—airports operated by the military, National

Aeronautics and Space Administration (NASA), or other agencies of the Federal Government. 

• Private Airports—airports designated for private or restricted use only, not open to the

general public. 

Towered Airport 

A towered airport has an operating control tower. Air traffic control (ATC) is responsible for 

providing the safe, orderly, and expeditious flow of air traffic at airports where the type of 

operations and/or volume of traffic requires such a service.

Non-towered Airport 

A non-towered airport does not have an operating control tower. Two-way radio communications 

are not required, although it is a good operating practice for pilots to monitor other aircraft on the 

specified frequency for the benefit of other traffic in the area. The key to monitoring traffic at an 

airport without an operating control tower is selection of the correct common frequency. The 

acronym CTAF, which stands for Common Traffic Advisory Frequency, is synonymous with this 

program. A CTAF is a frequency designated for the purpose of carrying out airport advisory practices 

while operating to or from an airport without an operating control tower. The CTAF may be a 

Universal Integrated Community (UNICOM), MULTICOM, FSS, or tower frequency and is identified in 

appropriate aeronautical publications. UNICOM is a nongovernment air/ground radio 

communication station that may provide airport information at public use airports where there is no 

tower or FSS. 

Non-towered airport traffic patterns are always entered at pattern altitude. How you enter the 

pattern depends upon the direction of arrival. The preferred method for entering from the 

downwind side of the pattern is to approach the pattern on a course 45 degrees to the downwind 

leg and join the pattern at midfield.

Sources for Airport Data 

When a remote pilot operates in the vicinity of an airport, it is important to review the current data for 

that airport. This data provides the pilot with information, such as communication frequencies, 

services available, closed runways, or airport construction. Three common sources of information are: 

• Aeronautical Charts 
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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 66

• Chart Supplement U.S. (formerly Airport/Facility Directory) 

• Notices to Airmen (NOTAMs) 

• Automated Terminal Information Service (ATIS) 

Chart Supplement U.S. (formerly Airport/Facility Directory) 

The Chart Supplement U.S. (formerly Airport/Facility Directory) provides the most comprehensive 

information on a given airport. It contains information on airports, heliports, and seaplane bases 

that are open to the public. The Chart Supplement U.S. is published in seven books, which are 

organized by regions and are revised every 56 days. The Chart Supplement U.S. is also available 

digitally at www.faa.gov/air_traffic/flight_info/aeronav. Figure 11-1 contains an excerpt from a 

directory. For a complete listing of information provided in a Chart Supplement U.S. and how the 

information may be decoded, refer to the “Legend Sample” located in the front of each Chart 

Supplement U.S.

Figure 11-1. Chart Supplement U.S. (formerly Airport/Facility Directory excerpt.

Notices to Airmen (NOTAM) 

Time-critical aeronautical information, which is of a temporary nature or not sufficiently known in 

advance to permit publication, on aeronautical charts or in other operational publications, that 

receives immediate dissemination by the NOTAM system. The NOTAM information could affect your 
Chapter 11: Airport Operations

Remote Pilot – Small Unmanned Aircraft Systems Study Guide 67

decision to make the flight. Although NOTAMs contain information such as taxiway and runway 

closures, construction, communications, changes in status of navigational aids, and other 

information essential to planned en route, terminal, or landing operations, a remote pilot can use 

this information to help them make an informed decision about where and when to operate their 

small UA. Exercise good judgment and common sense by carefully regarding the information readily 

available in NOTAMs. 

Prior to any flight, pilots should check for any NOTAMs that could affect their intended flight. For 

more information on NOTAMs, refer back to Chapter 2, “Airspace Classification, Operating 

Requirements, and Flight Restrictions,” of this study guide. 

Automated Terminal Information Service (ATIS) 

The Automated Terminal Information Service (ATIS) is a recording of the local weather conditions 

and other pertinent non-control information broadcast on a local frequency in a looped format. It is 

normally updated once per hour but is updated more often when changing local conditions warrant. 

Important information is broadcast on ATIS including weather, runways in use, specific ATC 

procedures, and any airport construction activity that could affect taxi planning. 

When the ATIS is recorded, it is given a code. This code is changed with every ATIS update. For 

example, ATIS Alpha is replaced by ATIS Bravo. The next hour, ATIS Charlie is recorded, followed by 

ATIS Delta and progresses down the alphabet.

Aeronautical Charts 

An aeronautical chart is the road map for a pilot. The chart provides information that allows remote 

pilots to obtain information about the areas where they intend to operate. The two aeronautical 

charts used by VFR pilots are: 

• Sectional 

• VFR Terminal Area 

A free catalog listing aeronautical charts and related publications including prices and instructions 

for ordering is available at the Aeronautical Navigation Products website: www.aeronav.faa.gov. 

Sectional Charts 

Sectional charts are the most common charts used by pilots today. The charts have a scale of 

1:500,000 (1 inch = 6.86 nautical miles (NM) or approximately 8 statute miles (SM)), which allows 

for more detailed information to be included on the chart.

The charts provide an abundance of information, including airport data, navigational aids, airspace, 

and topography. Figure 11-2 is an excerpt from the legend of a sectional chart. By referring to the 

chart legend, a pilot can interpret most of the information on the chart. A pilot should also check 

the chart for other legend information, which includes air traffic control (ATC) frequencies and 

information on airspace. These charts are revised semiannually except for some areas outside the 

conterminous United States where they are revised annually.
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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 68

Figure 11-2. Sectional chart and legend.

Latitude and Longitude (Meridians and Parallels)

The equator is an imaginary circle equidistant from the 

poles of the Earth. Circles parallel to the equator (lines 

running east and west) are parallels of latitude. They are 

used to measure degrees of latitude north (N) or south 

(S) of the equator. The angular distance from the 

equator to the pole is one-fourth of a circle or 90°. The 

48 conterminous states of the United States are located 

between 25° and 49° N latitude. The arrows in 

Figure 11-3 labeled “Latitude” point to lines of latitude. 

Meridians of longitude are drawn from the North Pole to 

the South Pole and are at right angles to the Equator. 

The “Prime Meridian,” which passes through Greenwich, 

England, is used as the zero line from which 

measurements are made in degrees east (E) and west 

(W) to 180°. The 48 conterminous states of the United 

Figure 11-3. Meridians and parallels—the basis of 

measuring time, distance, and direction.
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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 69

States are between 67° and 125° W longitude. The arrows in Figure 11-3 labeled “Longitude” point to 

lines of longitude. 

Any specific geographical point can be located by reference to its longitude and latitude. Washington, 

D.C., for example, is approximately 39° N latitude, 77° W longitude. Chicago is approximately 42° N 

latitude, 88° W longitude.

Variation 

Variation is the angle between true north (TN) and 

magnetic north (MN). It is expressed as east 

variation or west variation depending upon 

whether MN is to the east or west of TN.

The north magnetic pole is located close to 71° N 

latitude, 96° W longitude and is about 1,300 miles 

from the geographic or true north pole, as 

indicated in Figure 11-4. If the Earth were 

uniformly magnetized, the compass needle would 

point toward the magnetic pole, in which case the 

variation between TN (as shown by the 

geographical meridians) and MN (as shown by the 

magnetic meridians) could be measured at any 

intersection of the meridians. 

Actually, the Earth is not uniformly magnetized. In 

the United States, the needle usually points in the 

general direction of the magnetic pole, but it may 

vary in certain geographical localities by many 

degrees. Consequently, the exact amount of 

variation at thousands of selected locations in the 

United States has been carefully determined. The 

amount and the direction of variation, which 

change slightly from time to time, are shown on 

most aeronautical charts as broken magenta lines 

called isogonic lines that connect points of equal 

magnetic variation. (The line connecting points at 

which there is no variation between TN and MN is 

the agonic line.) An isogonic chart is shown in 

Figure 11-5. Minor bends and turns in the isogonic 

and agonic lines are caused by unusual geological 

conditions affecting magnetic forces in these areas.

Antenna Towers

Extreme caution should be exercised when flying less 

than 2,000 feet AGL because of numerous skeletal 

structures, such as radio and television antenna 

towers, that exceed 1,000 feet AGL with some 

Figure 11-4. Magnetic meridians are in red while the lines of 

longitude and latitude are in blue. From these lines of variation 

(magnetic meridians), on can determine the effect of local 

magnetic variations on a magnetic compass.

Figure 11-5. Note the agonic line where magnetic variation is 

zero.
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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 70

extending higher than 2,000 feet AGL. Most skeletal structures are supported by guy wires which are 

very difficult to see in good weather and can be invisible at dusk or during periods of reduced visibility. 

These wires can extend about 1,500 feet horizontally from a structure; therefore, all skeletal structures 

should be avoided horizontally by at least 2,000 feet. 

Additionally, new towers may not be on your current chart because the information was not received 

prior to the printing of the chart.
Remote Pilot – Small Unmanned Aircraft Systems Study Guide 71

Chapter 12:

Maintenance and Preflight Inspection Procedures

Maintenance and Preflight Inspection Procedures can be found in chapter 7 of Advisory Circular 107-2. 
Remote Pilot – Small Unmanned Aircraft Systems Study Guide 72

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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 74

A

Appendix 1:

Study References

Reference Title

14 CFR part 47 Aircraft Registration

14 CFR part 48 Registration and Marking Requirements for Small Unmanned 

Aircraft Systems

14 CFR part 71 Designation of Class A, B, C, D and E Airspace Areas; Air Traffic 

Service Rotes; and Reporting Points

14 CFR part 107 Operation and Certification of Small Unmanned Aircraft Systems

AC 00-6 Aviation Weather for Pilots and Flight Operations Personnel

AC 150/5200-32 Reporting Wildlife Aircraft Strikes

AC 107-2 Small Unmanned Aircraft Systems (sUAS)

AIM Aeronautical Information Manual

FAA-CT-8080-2 Airman Knowledge Testing Supplement for Sport Pilot, 

Recreational Pilot, and Private Pilot

FAA-G-8082-20 Remote Pilot Knowledge Test Guide

FAA-H-8083-1 Weight & Balance Handbook

FAA-H-8083-2 Risk Management Handbook

FAA-H-8083-25 Pilot’s Handbook of Aeronautical Knowledge 

FAA-S-ACS-10 Remote Pilot – Small Unmanned Aircraft Systems Airman 

Certification Standards

SAFO 09013 Fighting Fires Caused By Lithium Type Batteries in Portable 

Electronic Devices

SAFO 10015 Flying in the wire environment

SAFO 10017 Risks in Transporting Lithium Batteries in Cargo by Aircraft

SAFO 15010 Carriage of Spare Lithium Batteries in Carry-on and Checked 

Baggage

Note Users should reference the current edition of the reference documents listed above. 
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Appendix 2:

Registration and Marking Requirements for Small Unmanned Aircraft

Applicants must be familiar with all of the information in 14 CFR part 48, Registration and Marking 

Requirements for Small Unmanned Aircraft, especially the sections listed in the following table:

Section Title

48.15 Requirement to register

48.20 Eligibility for registration

48.25 Applicants

48.100 Application

48.205 Display and location of unique identifier
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Appendix 3:

Abbreviations and Acronyms

The following abbreviations and acronyms are used in this study guide.

Abb./Acronym Definition

14 CFR Title 14 of the Code of Federal Regulations

AC Advisory Circular

ACS Airman Certification Standards

ADDS Aviation Digital Data Services

ADIZ Air Defense Identification Zone

ADM Aeronautical Decision-Making

AFM Airplane Flight Manual

AFS Flight Standards Service

AGL Above Ground Level

AIRMET Airman’s Meteorological Information

AOA Angle of Attack

ATC Air Traffic Control

ATD Aviation Training Device

CB Cumulonimbus

CFA Controlled Firing Areas

CFR Code of Federal Regulations

CG Center of Gravity

CP Center of Pressure

CRM Crew Resource Management

CTAF Common Traffic Advisory Frequency

CTP Certification Training Program

DPE Designated Pilot Examiner

DVFR Defense VFR

EMS Emergency Services

FAA Federal Aviation Administration

FADEC Full Authority Digital Engine Control

FDA Federal Drug Administration

FDC Flight Data Center
Remote Pilot – Small Unmanned Aircraft Systems Study Guide 79

Abb./Acronym Definition

FL Flight Level

FRZ Flight Restriction Zone

FS Flight Service

FSDO Flight Standards District Office

IAP Instrument Approach Procedures

ICAO International Civil Aviation Organization

IFR Instrument Flight Rules

IR Instrument Routes (sectional charts)

ISA International Standard Atmosphere

LAA Local Airport Advisory

MAP Missed Approach Point

MDA Minimum Descent Altitude

MEL Minimum Equipment List

MFD Multi-functional Displays

MOA Military Operation Areas

MSL Mean Sea Level

MTR Military Training Route

NACG National Aeronautical Charting Group

NASA National Aeronautics and Space Administration

NAS National Airspace System

NM Nautical Miles

NOAA National Oceanic and Atmospheric Administration

NOTAM Notice to Airmen

NSA National Security Area

OTC Over-the-Counter

PAVE PIC – Aircraft – environment – External pressures

POH Pilot’s Operating Handbook

SAO Special Area of Operation

SIGMET Significant Meteorological Information

SOP Standard Operating Procedures

TCU Towering Cumulus

TFR Temporary Flight Restrictions

TN True North

TRSA Terminal Radar Service Area
Remote Pilot – Small Unmanned Aircraft Systems Study Guide 80

Abb./Acronym Definition

TUC Time of Useful Consciousness

UNICOM Aeronautical Advisory Communications Stations

UTC Coordinated Universal Time

VFR Visual Flight Rules

VR Visual Routs (sectional charts)

VO Visual Observer

W&B Weight and Balance

WST Convective Significant Meteorological Information