U.S. Department

of Transportation

Federal Aviation

Administration

Advisory

Circular

Subject: Enhanced Flight Vision Systems Date:

Initiated by: AFS-400

AC No: 90-106A

On January 9, 2004, the FAA published an Enhanced Fight Vision System (EFVS) final rule to 

permit an EFVS to be used in lieu of natural vision to descend below decision altitude (DA), 

decision height (DH), or minimum descent altitude (MDA) down to 100 feet above the 

touchdown zone elevation (TDZE). On (insert date of final rule), the FAA published a final rule 

that permitted an EFVS to be used in lieu of natural vision to continue descending from 100 feet 

above the TDZE to the runway and land on certain straight-in instrument approach procedures

(IAP). This final rule also permitted certain operators using EFVS-equipped aircraft to dispatch, 

release, or takeoff under instrument flight rules and to initiate and continue an approach when the 

destination airport weather is below authorized visibility minimums for the runway of intended 

landing. Additionally, this final rule established pilot training, recent flight experience, and 

proficiency requirements for operators who conduct EFVS operations. As a part of this 

regulatory action, the FAA moved Title 14 of the Code of Federal Regulations Part 91, 

§ 91.175(l) and (m) to new § 91.176. This advisory circular provides information about the 

regulatory requirements for EFVS operations and explains how to obtain authorization to 

conduct EFVS operations.

We have made every attempt to write EFVS regulations that are performance-based and not 

limited to a specific sensor technology. Such an approach accommodates future growth in realtime sensor technologies used in most EFVS and maximizes the benefits of rapidly evolving IAP

and advanced flight deck technology to increase access and throughput during low-visibility

operations.

John M. Allen

Director, Flight Standards Service
07/26/13 AC 90-106A

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Table of Contents

Paragraph Page

1. INTRODUCTION. .............................................................................................................................................1

1.1. PURPOSE......................................................................................................................................................1

1.2. APPLICABILITY............................................................................................................................................1

1.3. SCOPE..........................................................................................................................................................1

1.4. APPLICABLE REGULATIONS.........................................................................................................................2

1.5. APPLICABLE ADVISORY CIRCULARS. ..........................................................................................................3

1.6. CANCELLATION...........................................................................................................................................3

2. REGULATORY BACKGROUND, DEFINITIONS, AND LEVELS OF EFVS OPERATIONS ...............4

2.1. EFVS REGULATORY BACKGROUND............................................................................................................4

2.2. DEFINITION OF AN EFVS.............................................................................................................................5

2.3. PURPOSE OF AN EFVS.................................................................................................................................5

2.4. DEFINITION OF AN EFVS OPERATION. ........................................................................................................6

2.5. LEVELS OF EFVS OPERATION.....................................................................................................................6

3. REQUIREMENTS FOR EFVS OPERATIONS..............................................................................................8

3.1. EFVS I OPERATIONS (§ 91.176(B)).............................................................................................................8

3.2. EFVS II OPERATIONS (§ 91.176(A))..........................................................................................................18

3.3. CONSIDERATIONS FOR EFVS I AND EFVS II OPERATIONS........................................................................30

4. EFVS OPERATIONS WHEN THE REPORTED OR FORECAST VISIBILITY AT THE 

DESTINATION AIRPORT IS BELOW AUTHORIZED MINIMUMS..............................................................35

4.1. DISPATCH, FLIGHT RELEASE, OR TAKEOFF UNDER IFR WHEN THE REPORTED OR FORECAST VISIBILITY 

AT THE DESTINATION AIRPORT IS BELOW AUTHORIZED MINIMUMS.........................................................35

4.2. INITIATING OR CONTINUING AN APPROACH WHEN THE DESTINATION AIRPORT VISIBILITY IS BELOW 

AUTHORIZED MINIMUMS. .........................................................................................................................36

5. PILOT TRAINING REQUIREMENTS FOR EFVS OPERATIONS .........................................................38

5.1. REGULATORY REQUIREMENT FOR TRAINING. ...........................................................................................38

5.2. INITIAL GROUND TRAINING. .....................................................................................................................38

5.3. INITIAL FLIGHT TRAINING.........................................................................................................................43

5.4. EXCEPTIONS TO THE INITIAL GROUND AND FLIGHT TRAINING REQUIREMENTS OF 14 CFR 61.31(L)(1)

AND (L)(3).................................................................................................................................................46

5.5. RECURRENT OR DIFFERENCES TRAINING. .................................................................................................48

5.6. AIRCRAFT OR FLIGHT SIMULATOR TRAINING............................................................................................49

5.7. APPROVED EFVS TRAINING PROGRAM. ...................................................................................................49

6. RECENT FLIGHT EXPERIENCE AND PROFICIENCY REQUIREMENTS FOR EFVS 

OPERATIONS...........................................................................................................................................................51

6.1. RECENT FLIGHT EXPERIENCE REQUIREMENTS FOR EFVS OPERATIONS. ..................................................51

6.2. PROFICIENCY CHECK REQUIREMENTS FOR EFVS OPERATIONS. ...............................................................51

7. TRAINING FOR DISPATCHERS AND OTHER PERSONS AUTHORIZED TO EXERCISE 

OPERATIONAL CONTROL FOR EFVS OPERATIONS...................................................................................53

7.1. DISPATCH, FLIGHT RELEASE AND FLIGHT FOLLOWING CONSIDERATIONS................................................53

7.2. INITIAL TRAINING FOR DISPATCHERS AND OTHER PERSONS AUTHORIZED TO EXERCISE OPERATIONAL 

CONTROL. .................................................................................................................................................54

7.3. RECURRENT AND DIFFERENCES TRAINING FOR DISPATCH AND FLIGHT RELEASE PERSONNEL.................56

8. AIRCRAFT QUALIFICATION AND MAINTENANCE PROGRAM REQUIREMENTS.....................57
07/26/13 AC 90-106A

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8.1. GENERAL...................................................................................................................................................57

8.2. APPLICABILITY..........................................................................................................................................57

8.3. AIRCRAFT QUALIFICATION REQUIREMENTS..............................................................................................57

8.4. MAINTENANCE PROGRAM.........................................................................................................................58

9. MAINTENANCE TRAINING FOR EFVS OPERATIONS.........................................................................60

9.1. GENERAL...................................................................................................................................................60

9.2. MAINTENANCE TRAINING .........................................................................................................................60

10. OPERATIONAL APPROVAL PROCESS FOR EFVS OPERATIONS ....................................................62

10.1. APPROVAL PROCESS OVERVIEW. ..............................................................................................................62

10.2. AUTHORIZATIONS TO CONDUCT EFVS OPERATIONS. ...............................................................................63

10.3. APPROVAL PROCESS FOR EFVS I OPERATIONS CONDUCTED UNDER PART 91 SUBPART K, 121, 125, OR 

135 AND EFVS II OPERATIONS CONDUCTED UNDER PART 91, 121, 125, OR 135. ....................................65

10.4. APPROVAL PROCESS FOR EFVS OPERATIONS CONDUCTED UNDER PART 129..........................................66

10.5. WAIVERS TO CONDUCT EFVS OPERATIONS .............................................................................................67

APPENDIX A. ACRONYMS AND ABBREVIATIONS .....................................................................................A-I

APPENDIX B. DEFINITIONS...............................................................................................................................B-I

APPENDIX C. RELATED PUBLICATIONS ......................................................................................................C-I

C-1. RELATED PUBLICATIONS. .............................................................................................................................. C-I

C-2. HOW TO GET PUBLICATIONS. .......................................................................................................................C-II

Table of Figures

Figure 1 View during an approach with EFVS (left) and without EFVS (right). (Images courtesy 

of NASA Langley Research Center)............................................................................................... 6

Figure 2 EFVS I Operational Concept............................................................................................ 9

Figure 3 Based on a 17oviewing angle from the cockpit and visibility limitations due to weather, 

a pilot might expect to see three or four sequenced flashers and approximately five rows of 

approach lights on an ALSF-2 or MALSR lighting system upon arrival at a 200-foot DA with a 

flight visibility of RVR 2400. ....................................................................................................... 14

Figure 4 Graphic depiction of what a pilot’s view might be of a MALSR upon arrival at a 200-

foot DA with a flight visibility of RVR 2400 feet on a 3° glideslope. ......................................... 14

Figure 5 EFVS II Operational Concept ........................................................................................ 20

Figure 6 Use of EFVS on a Precision Approach .......................................................................... 28

Figure 7 Use of EFVS on an Approach With Approved (Published) Vertical Guidance............. 28

Figure 8 Use of EFVS on a Nonprecision Approach.................................................................... 29

Table of Tables

Table 1 Required Visual References............................................................................................ 16
07/26/13 AC 90-106A

1

1. Introduction.

1.1. Purpose.

This advisory circular (AC) provides information about the operating rules pertaining to 

Enhanced Flight Vision System (EFVS) operations and explains how to obtain authorization to 

conduct EFVS operations.

1.2. Applicability.

This AC applies to all EFVS operations conducted to 100 feet above the touchdown zone 

elevation (TDZE) and all EFVS operations conducted to touchdown and rollout under §§ 91.176, 

91.189, 121.651, 125.381, and 135.225. This AC also applies to the EFVS provisions of 

§§ 121.613, 121.615, 125.361, 125.363, and 135.219 for dispatch, flight release, and takeoff 

under Instrument Flight Rules (IFR) when the reported or forecast visibility at the destination 

airport is below authorized minimums. In addition, this AC applies to the EFVS provisions of 

§§ 121.651, 125.325, 125.381, and 135.225 for initiating or continuing an approach when the 

destination airport weather is below authorized visibility minimums for the runway of intended 

landing.

Note: The European Aviation Safety Agency (EASA) and other foreign civil 

aviation authorities (CAAs) use the term “Enhanced Vision System (EVS)” rather 

than the term “Enhanced Flight Vision System (EFVS),” which is used by the 

FAA. Both terms refer to a vision system that aviation authorities permit pilots to 

use in lieu of natural vision for certain specified operations. You should not 

confuse use of the term “EVS” in this context with an EVS that the FAA does not 

permit pilots to use in lieu of natural vision to descend below DA/DH or MDA 

(see Section 1.3.4).

1.3. Scope.

1.3.1. This AC provides the methods, procedures, and practices acceptable to the FAA for 

complying with regulations. It is one means, but not the only means of obtaining 

authorization to conduct EFVS operations. This AC does not alter regulatory 

requirements.

1.3.2. The sections in this AC provide information on the following subject areas:

 Regulatory background of EFVS operations;

 Levels of EFVS operations which can be currently approved;

 The concept of operation associated with each level of EFVS operation;

 Regulatory requirements for conducting EFVS operations, including operating;

equipment, training, recent flight experience, proficiency, dispatch and flight release, 

and maintenance requirements; and

 How to obtain operational approval to conduct EFVS operations.

1.3.3. This AC does not address the use of EFVS for lower than standard takeoff minima. 

Section 91.175(f) prescribes civil airport takeoff minimums that are applicable to persons 
07/26/13 AC 90-106A

2

conducting operations under Part 121, 125, 129, or 135. Section 91.175(f) makes 

provision for the FAA to authorize takeoff minimums other than those specifically

prescribed in that section. Using this provision, lower than standard takeoff minimums 

can be authorized for EFVS through existing processes. The FAA, however, has not yet 

developed operational requirements or guidance material for this operation. .

1.3.4. This AC does not address the use of EFVS on Category (CAT) II or CAT III Instrument 

Approach Procedures (IAPs). While § 91.189 and existing operational approval processes 

for CAT II and CAT III operations permit an appropriately certified EFVS to be used as 

part of these operations, the FAA has not yet developed operational requirements or 

guidance material for using an EFVS for other than situation awareness on a CAT II or 

CAT III IAP.

1.3.5. This AC does not address the use of EVS. An EVS is an electronic means to provide the 

flightcrew with a sensor-derived or enhanced image of the external scene using 

millimeter wave radar, forward-looking infrared (FLIR), or other sensor technologies to 

provide a real-time image of the external scene. An EVS is not the same as an EFVS, 

however. Unlike an EFVS, an EVS may present a sensor image on a head-down display

(HDD), may not provide the additional flight information or symbology required by

§ 91.176, and may not be able to present the image and flight symbology in the same 

scale and alignment as the outside view. It is important to note that an EVS can also use a 

head-up display (HUD) as its display element, yet still not meet the regulatory

requirements for an EFVS. While an EVS that uses an HDD or HUD may provide 

situation awareness to the pilot, it does not meet the airworthiness standards of Part 23, 

25, 27, or 29 for an EFVS, nor does it meet the requirements for EFVS operations under 

§§ 91.176, 121.651, 125.381, or 135.225. Consequently, a pilot cannot use an EVS in lieu 

of natural vision to descend below DA/DH or MDA under these regulations.

1.3.6. This AC does not address the use of synthetic vision systems (SVS), which use a 

computer-generated image of the external scene topography from the perspective of the 

flight deck. The synthetic vision image is derived from aircraft attitude, a high-precision 

navigation solution, and a database of terrain, obstacles, and relevant cultural features. 

Unlike an EFVS, an SVS does not provide an independent, real-time source of forward 

scene information. A pilot cannot use a synthetic vision image on an HDD or HUD in 

lieu of natural vision to descend below DA/DH or MDA under the regulations.

1.4. Applicable Regulations.

 Part 1, § 1.1

 Part 23, § 23.773(c)

 Part 25, § 25.773(e)

 Part 27, § 27.773(c)

 Part 29, § 29.773(c)

 Part 61, §§ 61.31(l), 61.57(h) and (i)

 Part 91, §§ 91.175(d)(1), 91.175(e)(1), 91.176, 91.189(d) and (e), 91.905

 Part 121, §§ 121.613, 121.615(a), 121.651

 Part 125, §§ 125.325, 125.361, 125.363(a), 125.381
07/26/13 AC 90-106A

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 Part 135, §§ 135.219, 135.225

1.5. Applicable Advisory Circulars.

1.5.1. Certification criteria for EFVS equipment used to conduct EFVS operations under 

§ 91.176 is contained in AC 20-167A, Airworthiness Approval of Enhanced Vision 

System, Synthetic Vision System, Combined Vision System, and Enhanced Flight Vision 

System Equipment.

1.5.2. Certification criteria for HUDs is contained in AC 25-11A, Change 1, Electronic Flight 

Deck Displays.

1.5.3. You can find a list of related or supporting ACs and publications in Appendix 3.

1.5.4. You can order copies of FAA ACs from the United States Department of Transportation, 

Subsequent Distribution Office, M-30, Ardmore East Business Center, 3341 Q 75th 

Avenue, Landover, MD 20785. You can also obtain copies from the FAA Web site at 

www.airweb.faa.gov or www.faa.gov by clicking on the link “Regulatory and Guidance 

Library.”

1.6. Cancellation.

This AC cancels AC 90-106, Enhanced Flight Vision Systems, dated June 2, 2010.
07/26/13 AC 90-106A

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2. Regulatory Background, Definitions, and Levels of EFVS Operations

2.1. EFVS Regulatory Background.

2.1.1. The requirements for operating below DA/DH or MDA under instrument flight rules 

(IFRs) on instrument approaches to civil airports are contained in §§ 91.175 and 

§ 91.176. The FAA has modified these requirements over the years to enable aircraft 

operations during reduced visibility conditions while maintaining a high level of safety. 

For many years, descent below DA/DH or MDA could only be accomplished using 

natural vision (see § 91.175(c)). On January 9, 2004, the FAA published a final rule in 

the Federal Register, Enhanced Flight Vision Systems (69 FR 1620), that expanded 

operational capability by permitting EFVS to be used in lieu of natural vision to continue 

descending below DA/DH or MDA to 100 feet above the TDZE on a straight-in IAP 

other than CAT II or CAT III. At and below 100 feet, however, the lights or markings of 

the threshold or the lights or markings of the touchdown zone (TDZ) had to be distinctly

visible and identifiable to the pilot using natural vision. A pilot could not continue to 

descend below 100 feet by relying solely on the EFVS sensor imagery. The 2004 final 

rule also established equipment requirements for EFVS operations and introduced 

definitions for EFVS and enhanced flight visibility.

2.1.2. On (insert date of final rule), the FAA published a final rule in the Federal Register, 

Revisions to Operational Requirements for the Use of Enhanced Flight Vision Systems 

(EFVS) and to Pilot Compartment View Requirements for Vision Systems (__ FR ____), 

that further expanded operational capability for EFVS by permitting pilots to use it in lieu 

of natural vision to continue descending below 100 feet to touchdown and rollout on a 

straight-in precision IAP or an IAP with a published vertical path. This regulatory action 

effectively permitted a pilot to use an appropriately certified EFVS in lieu of natural 

vision to descend below DA/DH all the way to touchdown and rollout. This final rule 

also established equipment requirements for EFVS to touchdown operations and 

amended the visual reference requirements for EFVS operations conducted below 

DA/DH or MDA down to 100 feet and for EFVS operations conducted below DA/DH to 

touchdown and rollout.

2.1.3. In addition to permitting pilots to use EFVS in lieu of natural vision to descend below 

DA/DH to touchdown and rollout, the (insert year) final rule contained other amendments

that affect EFVS operations. The FAA amended the definition of EFVS in § 1.1 to more 

precisely describe an EFVS and added a definition for EFVS operation. The FAA also 

amended the regulations to specify conditions under which an aircraft equipped with 

EFVS could be dispatched, released, or permitted to take off under IFR. It also specified 

the conditions under which an operator of an EFVS-equipped aircraft may begin an 

approach when the weather is reported to be below authorized minimums for the 

approach to be flown. The FAA amended Part 61 to require initial training and establish 

recent flight experience and proficiency requirements for EFVS operators conducting 

approaches using EFVS to ensure that an appropriate level of safety is maintained for all 

EFVS operations. As part of this rulemaking action, the FAA also amended the 

regulations to permit operators to use an EFVS during CAT II and CAT III approaches.
07/26/13 AC 90-106A

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2.1.4. Finally, the (insert year) final rule consolidated all of the EFVS requirements in Part 91

into new § 91.176 for organizational and regulatory clarity. The FAA moved and 

restructured the regulations for EFVS to 100 feet operations that were located in 

§§ 91.175(l) and (m) to § 91.176. Section 91.176(a) contains the new regulations for 

EFVS operations to touchdown and rollout, and § 91.176(b) contains the regulations for 

EFVS operations that are conducted to 100 feet above the TDZE. Sections 91.176(a) and 

(b) are each organized into three main areas – equipment requirements, operating 

requirements, and visibility and visual reference requirements.

2.2. Definition of an EFVS.

2.2.1. Imaging-sensor technologies can offer significant advantages in both safety and 

capability for low-visibility flight operations. 14 CFR part 1, § 1.1 defines an EFVS as 

follows: “Enhanced Flight Vision System (EFVS) means an installed aircraft system 

which uses an electronic means to provide a display of the forward external scene 

topography (the applicable natural or manmade features of a place or region especially in 

a way to show their relative positions and elevation) through the use of imaging sensors, 

such as forward-looking infrared, millimeter wave radiometry, millimeter wave radar, or 

low-light level image intensification. The EFVS sensor imagery and required aircraft 

flight information and flight symbology is displayed on a head-up display, or an 

equivalent display, so that the imagery and symbology is clearly visible to the pilot flying 

in his or her normal position with the line of vision looking forward along the flight path. 

An EFVS includes the display element, sensors, computers and power supplies, 

indications, and controls.”

2.3. Purpose of an EFVS.

2.3.1. An EFVS uses a transparent HUD to combine flight information, flight symbology,

navigation guidance, and a real-time image of the external scene to the pilot on one 

display. Imaging sensors, which may be based on FLIR, millimeter wave radiometry, 

millimeter wave radar, low-level light intensification, or other real-time imaging 

technologies produce a real-time image of the outside scene. The EFVS aligns and scales 

the sensor image, along with the aircraft flight information and flight symbology on the 

HUD, with the external scene as viewed from the pilot’s perspective through the 

windscreen. Depending on atmospheric conditions and the strength of energy emitted 

and/or reflected from the outside scene, an EFVS can enable a pilot to see the approach 

lights, visual references associated with the runway environment, and other objects or 

features that might not be visible using natural vision alone.

2.3.2. During an instrument approach, the purpose of the EFVS image is to enhance the pilot’s 

ability to detect and identify the visual references for the runway of intended landing 

before they are visible naturally out the windscreen (See Figure 1). Combining the flight 

information, navigation guidance, and sensor imagery on a HUD allows the pilot to 

remain head up and to continue looking forward along the flight path throughout the 

entire approach, landing, and rollout. The overall purpose of an EFVS is to enable a pilot 

to use enhanced vision imagery in lieu of natural vision to descend below DA/DH or 

MDA, depending on the level of EFVS operation for which the equipment and operator 
07/26/13 AC 90-106A

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are approved. Use of an EFVS may improve safety by enhancing situation and position 

awareness, providing visual cues to maintain a stabilized approach, and minimizing 

missed approach situations.

2.3.3. In addition to using an EFVS to satisfy the requirements of § 91.176, an EFVS may allow 

the pilot to visually detect an obstruction on the runway, such as an aircraft or vehicle, 

earlier in the approach, and avoid potential runway incursions during ground operations 

in reduced-visibility conditions. Even in situations where the flight visibility under 

§ 91.175(c)(2) is sufficient for a pilot to use natural vision to descend below DA/DH or 

MDA, an EFVS may provide useful visual cues for enhanced situation awareness.

Figure 1 View during an approach with EFVS (left) and without EFVS (right). (Images courtesy of NASA 

Langley Research Center)

2.4. Definition of an EFVS Operation.

2.4.1. Section 1.1 defines an EFVS operation as “an operation in which an EFVS is required to 

be used to perform an approach or landing, determine enhanced flight visibility, identify

required visual references, or conduct the rollout.” This definition establishes the 

conditions under which an EFVS is required to conduct specific operations. While an 

EFVS can provide situation awareness in any phase of flight, such use would not 

constitute an EFVS operation unless an EFVS is required to be used to perform an 

approach or landing in lieu of natural vision, determine enhanced flight visibility, identify

required visual references, or conduct the rollout. A pilot who uses an EFVS to provide 

situation awareness on that portion of an IAP down to DA/DH or MDA is not conducting 

an EFVS operation. A pilot who uses an EFVS in lieu of natural vision to determine 

enhanced flight visibility and to identify the required visual references to descend below 

DA/DH or MDA, however, is conducting an EFVS operation. Similarly, a pilot who is 

required to use an EFVS for rollout is also conducting an EFVS operation.

2.5. Levels of EFVS Operation.

2.5.1. Although the terms “EFVS I” and “EFVS II” are not included in the regulations, the FAA 

uses these terms to facilitate the issuance of operational approvals. “EFVS I” refers to 

operations that are conducted under the provisions of § 91.176(b), and “EFVS II” refers 
07/26/13 AC 90-106A

7

to operations that are conducted under the provisions of § 91.176(a). Accordingly, the 

FAA categorizes EFVS operations into two levels as follows:

 EFVS I - The installed EFVS has been demonstrated to meet the criteria for 

AC 20-167A for EFVS I to be used for instrument approach operations from DA/DH 

or MDA down to 100 ft height above the touchdown zone elevation.

 EFVS II - The installed EFVS has been demonstrated to meet the criteria for 

AC 20-167A for EFVS II to be used for instrument approach and landing operations 

that rely on sufficient visibility conditions to enable unaided rollout and to mitigate 

for loss of EFVS function. An EFVS that meets the certification criteria for EFVS II 

also meets the certification criteria for EFVS I.

Flight Standards (AFS) currently authorizes operators to conduct EFVS II operations 

on a straight-in IAP from DA/DH to touchdown down to visibilities as low as a 

Runway Visual Range (RVR) of 1000 feet, depending on what an applicant

demonstrated for the EFVS equipment during certification flight test. 

2.5.2. It is important to understand that the EFVS regulations contained in § 91.176 do not 

specify visibility limitations. Rather, they provide a regulatory framework that enables 

the FAA to approve and manage EFVS operations to any visibility, including visibilities 

lower than RVR 1000, based on the demonstrated capability of the EFVS equipment and 

an operator’s ability to perform the EFVS operations for which they seek approval. This 

regulatory framework permits Flight Standards to specify visibility and other operating 

conditions and limitations through an operator’s Operations Specification (OpSpec), 

Management Specifications (MSpec), or Letter of Authorization (LOA) for EFVS 

operations. For certain future EFVS operations, § 91.176(a)(1)(ii) specifies that the 

Administrator may require the display of the EFVS sensor imagery, required aircraft 

flight information, and flight symbology to be provided to the pilot monitoring on a HUD

or other equivalent display appropriate to the operation being conducted. The FAA made 

this regulatory provision to provide a means to respond to future advancements in sensor 

or display technology that could operate in very low visibilities.
07/26/13 AC 90-106A

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3. Requirements for EFVS Operations

3.1. EFVS I Operations (§ 91.176(b))

3.1.1. Operational Concept for EFVS I Operations.

3.1.1.1. You can find the regulations pertaining to EFVS I operations in § 91.176(b). Under 

§ 91.175(c) and § 91.176(b), there are two means of operating visually below DA/DH 

or MDA in the visual segment of an IAP. One means is by using natural vision under 

§ 91.175(c), and the other is by using enhanced vision provided by an EFVS under 

§ 91.176(b). An EFVS I operation is an operation in which the pilot uses the enhanced 

vision imagery provided by an EFVS in lieu of natural vision to descend below DA/DH 

or MDA down to 100 feet above the TDZE on certain IAPs (see Figure 2). To use an 

EFVS to descend below DA/DH or MDA, the pilot must meet certain enhanced flight 

visibility, visual reference, and operating requirements. At 100 feet above the TDZE

and below, the pilot must transition from enhanced vision to natural vision and must be 

able to identify the required visual references using natural vision without reliance on 

the EFVS to continue to a landing. In other words, the pilot cannot continue to descend

below 100 feet by relying solely on the EFVS sensor image. The pilot must be able to 

identify the required visual references using natural vision or the pilot cannot continue 

to descend below 100 feet above the TDZE. The regulations do not require the pilot to 

turn off or stow the EFVS to descend below 100 feet above the TDZE, nor do they

require removing the sensor image from the EFVS display to continue to a landing 

without reliance on the sensor image. As long as the pilot can see the required visual 

references that he or she would normally see through the HUD with natural vision, the

pilot can meet the regulatory requirement. The pilot must base the decision to continue 

descending below 100 feet above the TDZE on seeing the required visual references 

through the EFVS display by means of natural vision.

3.1.1.2. Section 91.176(b) permits a pilot to use an EFVS to identify the required visual 

references and to determine that the enhanced flight visibility provided by the EFVS is 

not less than the visibility prescribed in an IAP. Both the visual reference and enhanced 

flight visibility requirements must be met before the pilot can descend below DA/DH or 

MDA down to 100 feet above the TDZE. This AC discusses enhanced flight visibility

and required visual references associated with EFVS I operations in detail in Sections 

3.1.4 and 3.1.5, respectively. In addition to the visual reference and enhanced flight 

visibility requirements, the regulations require that the aircraft be continuously in a 

position from which a pilot can descend to a landing on the intended runway at a normal 

rate of descent using normal maneuvers. The regulations also require that the descent 

rate allow touchdown to occur within the touchdown zone of the runway of intended 

landing for operations conducted under Part 121 or 135.

3.1.1.3. It is important to understand that using an EFVS does not result in obtaining lower

minima with respect to the visibility specified in the IAP, the DA/DH, or the MDA. An 

EFVS simply provides another means, other than that of natural vision, of operating in 

the visual segment of an IAP. For example, a pilot who is using an EFVS on a CAT I 

Instrument Landing System (ILS) approach that specifies a DA of 200 feet and a 
07/26/13 AC 90-106A

9

required visibility of 1⁄2 statute mile (SM) must comply with a 200-foot DA and an 

enhanced flight visibility of 1⁄2 SM, even though the pilot may not have 1⁄2 SM mile 

flight visibility using natural vision or 1⁄2 SM reported visibility. The fact that the pilot

can use an EFVS in lieu of natural vision to descend below the DA in this example

down to 100 feet above the TDZE does not lower the DA or visibility minima specified 

in the IAP. The DA is still at 200 feet, and the visibility requirement is still 1⁄2 SM. The 

difference is whether the pilot assesses the 1⁄2 SM visibility prescribed by the IAP using 

natural vision or whether the pilot assesses it using an EFVS. People often misinterpret

the benefit of EFVS by thinking it provides a lower decision altitude of 100 feet. This 

is not correct. The decision altitude is specified by the IAP the pilot is flying, and it 

does not change whether EFVS is used or not. The 100-ft altitude is simply an altitude

along the approach path where a different set of visual references must be seen to 

continue descending. In the case of an EFVS I operation, the 100-ft altitude is also 

where the pilot must transition to natural vision to identify the required visual 

references to continue descending. What EFVS does, is give the pilot another means, 

other than using natural vision, to operate below decision altitude. Specifically, it gives 

the pilot another means to distinctly see and identify the required visual references 

when he or she might not be able to do so using natural vision, and it gives the pilot a 

means to see forward along the flightpath the distance required by the IAP -- called 

enhanced flight visibility – when the pilot might not be able to do so using natural 

vision.

Figure 2 EFVS I Operational Concept
07/26/13 AC 90-106A

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3.1.2. Equipment Requirements for EFVS I Operations.

3.1.2.1. An EFVS installed on a U.S.-registered aircraft used to conduct an EFVS I operation 

must be operable and must be installed in accordance with an FAA type design approval 

(a type certificate (TC), amended type certificate (ATC), or supplemental type 

certificate (STC)). A field approval is not an acceptable means of EFVS installation for 

operations conducted under § 91.176(b). A foreign-registered aircraft used to conduct 

EFVS operations that does not have an FAA type design approval must be equipped 

with an operable EFVS that otherwise meets the requirements of the U.S. regulations.

3.1.2.2.An EFVS used to conduct EFVS I operations is an installed system that includes: 

 The display element, which is a HUD or an equivalent display, that presents the 

aircraft flight information, features, and characteristics required by the regulations 

such that they are clearly visible to the pilot flying in his or her normal position and 

line of vision looking forward along the flight path. A head-down display (HDD)

does not meet the regulatory requirement for the display element because it is not a 

head-up presentation that permits the pilot to see the EFVS sensor imagery and 

aircraft flight symbology while seated in his or her normal position and line of 

vision looking forward along the flight path. The regulations do make provision, 

however, for head-up presentations, other than a HUD, that the FAA might find

acceptable;

 Sensors that provide a real-time image of the forward external scene topography;

 Computers and power supplies;

 Indications; and 

 Controls.

3.1.2.3.At a minimum, the EFVS must display the following specific aircraft flight information: 

 Airspeed;

 Vertical speed;

 Aircraft attitude;

 Heading;

 Altitude;

 Command guidance as appropriate for the approach to be flown;

 Path deviation indications;

 Flight path vector (FPV) cue; and 

 Flight path angle reference cue (FPARC).
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3.1.2.4. The regulations also specify that the EFVS imagery, attitude symbology, FPV, FPARC, 

and other cues that are referenced to the imagery and external scene topography must be 

conformal. That is, they must be aligned with and scaled to the external view. In 

addition, the EFVS must display the FPARC with the pitch scale, and the pilot must be 

able to select the appropriate descent angle for the approach. The EFVS must display

the sensor imagery and aircraft flight symbology so that they do not adversely obscure 

the pilot’s outside view or field of view through the cockpit window. Finally, the 

display characteristics and dynamics must be suitable for manual control of the aircraft.

3.1.2.5. Many EFVS-equipped aircraft provide a display of the sensor imagery to the pilot 

monitoring. For EFVS I operations, the aircraft is not required to be equipped with a 

display that provides the pilot monitoring with EFVS sensor imagery. If the aircraft is 

equipped with a display of sensor imagery for the pilot monitoring, however, it can be 

an HDD, a dual EFVS installation, a head-mounted display, or other head up 

presentation.

3.1.2.6. A radio altimeter is not required under § 91.176(b) to conduct an EFVS I operation. The 

only exception to this would be an EFVS I operation that is conducted on a Special 

Authorization (SA) CAT I IAP, which specifies the use of a DH based on radio altitude. 

EFVS I operations conducted on a precision IAP or an approach with approved vertical 

guidance that utilizes a DA, or a nonprecision instrument approach that utilizes an 

MDA, are based on the use of a barometric altimeter.

3.1.2.7. An EFVS that has been certified only for EFVS I operations cannot be used to conduct 

EFVS II operations.

3.1.2.8. The Aircraft Flight Manual (AFM) or Aircraft Flight Manual Supplement (AFMS) that 

is approved for the aircraft must contain EFVS provisions appropriate to the EFVS 

operations to be conducted. An EFVS that the FAA certified after (insert date of final 

rule) will contain all of the following statements for EFVS I operations:

 “The installed EFVS has been demonstrated to meet the criteria specified in

AC 20-167A for EFVS I to be used for instrument approach operations from 

DA/DH or MDA down to 100 ft height above touchdown zone elevation.”

 “During certification flight test, the lowest visibility and the maximum final 

approach course offset angle at which the installed EFVS was demonstrated to be 

used in lieu of natural vision to descend below DA/DH or MDA and complete a 

landing in accordance with 14 CFR § 91.176(b) was<insert RVR value or SM 

value> and <insert angle in degrees>, respectively.”

3.1.2.9. The AFM/AFMS for an EFVS that was certified before (insert date of final rule) will

contain one of the following statements (or a similar statement) for EFVS I operations:

 “The installed <insert manufacturer’s name, make, and model> Enhanced Flight 

Vision System complies with AC 20-Vision System performance criteria for 

operational credit under 14 CFR § 91.175(l). The demonstrated lateral and vertical

displays meet the criteria for <types of approach>.” or
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 “EVS as installed meets the requirements of EFVS (Enhanced Flight Vision 

System) as defined in FAR 91.175.”

3.1.2.10.In addition to the statements described in Sections 3.1.2.8 and 3.1.2.9, an AFM/AFMS 

may contain additional operating conditions and limitations that are applicable to the 

installed EFVS equipment. 

3.1.3. Approaches Approved for EFVS I Operations.

3.1.3.1. A pilot may conduct an EFVS I operation on any standard or special IAP that is straightin and that uses published straight-in minima, provided all of the requirements of the 

regulations are met (§§ 91.176, 121.651, 125.381, and 135.225, as appropriate). This 

includes straight-in precision approaches such as ILS (CAT I, II, and III), microwave 

landing system (MLS), Precision Approach Radar (PAR), and ground based 

augmentation system [GBAS] landing system (GLS), straight-in approaches with 

published vertical guidance such as lateral approach procedures with vertical guidance 

(LPV), and lateral navigation/vertical navigation (LNAV/VNAV), and straight-in 

nonprecision approaches such as VHF omni-directional range station (VOR), 

nondirectional radio beacon (NDB), localizer (LOC), area navigation (RNAV), global 

positioning system (GPS), localizer-type directional aid (LDA), simplified directional 

facility (SDF), etc.

Note: While § 91.189 and existing operational approval processes for CAT II 

and CAT III operations permit an operator to use an appropriately certified 

EFVS as part of these operations, the FAA has not yet developed operational 

requirements or guidance material for using an EFVS for other than situation 

awareness on a CAT II or CAT III IAP.

3.1.3.2. An instrument approach with a circle-to-land maneuver or circle-to-land minimums 

does not meet the criteria for straight-in landing minimums. While the regulations do 

not prohibit a pilot from using EFVS during any phase of flight, they do prohibit a pilot 

from using it in lieu of natural vision to descend below DA/DH or MDA on anything 

but a straight-in IAP with straight-in landing minima. A pilot may only use EFVS 

during a circle-to-land maneuver provided the visual references required throughout the 

circling maneuver are distinctly visible using natural vision. An EFVS may not be used 

to satisfy the § 91.175(e)(2) requirement that an identifiable part of the airport be 

distinctly visible to the pilot during a circling maneuver at or above MDA or while 

descending below MDA from a circling maneuver. The pilot must accomplish this

using natural vision.

3.1.4. Enhanced Flight Visibility Requirements for EFVS I Operations.

3.1.4.1. For EFVS I operations conducted under §§ 91.176, 121.651, 125.381, and 135.225, the 

regulations state that no pilot may operate an aircraft at any airport below the authorized 

DA/DH or MDA and land unless the pilot determines that the enhanced flight visibility

observed by use of a certified EFVS is not less than the visibility prescribed in the IAP 

the pilot is using. The EFVS requirements for enhanced flight visibility under 
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§ 91.176(b) are analogous to the flight visibility requirements for natural vision under 

§ 91.175(c). To descend below DA/DH or MDA using natural vision under § 91.175(c), 

a pilot must make a determination that the flight visibility observed from the cockpit is 

not less than what is prescribed in the IAP being flown. The same is true for EFVS. 

Under § 91.176(b), a pilot must make a determination that the enhanced flight visibility

observed by using an EFVS is not less than what is prescribed in the IAP being flown 

before descending below DA/DH or MDA. Essentially, a pilot must accomplish the 

same basic tasks before descending below DA/DH or MDA using EFVS that he or she 

would using natural vision to conduct an approach under § 91.175(c) – assess that the 

“enhanced” flight visibility is not less than that specified in the IAP the pilot is flying, 

identify the required visual references for descent below DA/DH or MDA, assure the 

aircraft is continuously in a position to land on the intended runway at a normal rate of 

descent using normal maneuvers, and for operations conducted under Part 121 or 135, 

assure that the descent rate will allow touchdown to occur within the TDZ.

3.1.4.2. It is important to understand that, for a prescribed visibility value, the “sight picture” of 

the relevant visual references that the pilot can see looking forward along the flight path 

from the cockpit should be similar whether the pilot is using natural vision or an EFVS. 

An EFVS often produces the required enhanced flight visibility when actual reported 

visibility is much less. The point of this discussion is that even though actual visibility

may be less, as long as the EFVS provides the required enhanced flight visibility and a 

pilot meets all of the other requirements of the regulations, the pilot can continue 

descending below DA/DH or MDA using the EFVS. It is important that pilots receive 

training on how to assess enhanced flight visibility and what the “sight picture” should 

look like. How much of the forward scene, consisting of the approach lighting system

(ALS) or other elements, a pilot sees at DA/DH or MDA under prescribed visibility

conditions depends on individual instrument approach procedure construction 

(geometry, threshold crossing height, slant range distance from the cockpit to relevant 

visual references, etc.), cockpit cutoff angle, and other relevant factors. As visibility

conditions decrease, the ability of an EFVS to “see through” those conditions may also 

decrease. Under low or deteriorating visibility conditions, the ability to properly assess 

whether the required enhanced flight visibility exists to continue an approach becomes 

even more critical. The purpose of this discussion is not to suggest that a pilot should 

count approach lights to determine that the enhanced flight visibility is not less than 

what the IAP prescribes. Rather, it is to emphasize that through proper training, a pilot 

can learn to form a quick mental representation of what the visual scene should look 

like. In this example, the pilot should be able to see slightly further than the 1000-foot 

bar on the Medium-intensity Approach Lighting System with Runway Alignment 

Indicator Lights (MALSR). If the pilot sees less than this, the required enhanced flight 

visibility does not exist for this example approach and the pilot should execute a missed 

approach. It is important to remember that the sight picture will vary depending on what 

type of ALS is present. Figure 3 and Figure 4 show an example “sight picture” of what 

a pilot might expect to see upon arrival at a 200-foot DA with a flight visibility of RVR 

2400 feet on a 3-degree glideslope (GS).
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Figure 3 Based on a 17oviewing angle from the cockpit and visibility limitations due to weather, a pilot might 

expect to see three or four sequenced flashers and approximately five rows of approach lights on an ALSF-2 

or MALSR lighting system upon arrival at a 200-foot DA with a flight visibility of RVR 2400 feet.

Figure 4 Graphic depiction of what a pilot’s view might be of a MALSR upon arrival at a 200-foot DA with a 

flight visibility of RVR 2400 feet on a 3° GS.

3.1.4.3. For EFVS I operations, there are different visibility requirements in the part of the 

visual segment extending from DA/DH or MDA down to 100 feet above the TDZE than 

there are at and below 100 feet above the TDZE. From DA/DH or MDA down to 100 

feet, the enhanced flight visibility observed by use of a certified enhanced flight vision 

system cannot be less than the visibility prescribed in the instrument approach 

procedure being used (§ 91.176(b)(3)(i)). At and below 100 feet above the TDZE, 
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however, the enhanced flight visibility requirement no longer applies. At and below 100 

feet above the TDZE, a pilot cannot continue to rely on EFVS and must transition to 

natural vision to identify the required visual references. At and below 100 feet above 

the TDZE, the flight visibility only has to be sufficient for one of the required visual 

references specified in § 91.176(b)(3)(iii) to be distinctly visible and identifiable.

3.1.5. Visual Reference Requirements for EFVS I Operations.

3.1.5.1. To descend below DA/DH or MDA, the following visual references specified in 

§ 91.176(b)(3)(ii) for the runway of intended landing must be distinctly visible and 

identifiable to the pilot using the EFVS:

1. The approach light system (if installed); or 

2. The following visual references in both 2(a) AND 2(b) below:

a. The runway threshold, identified by at least one of the following: 

 The beginning of the runway landing surface;

 The threshold lights; or 

 The runway end identifier lights (REIL).

b. The touchdown zone, identified by at least one of the following: 

 The runway touchdown zone landing surface;

 The touchdown zone lights;

 The touchdown zone markings; or 

 The runway lights.

3.1.5.2. The main differences between the visual reference requirements for an approach using 

natural vision and one using EFVS are that, for EFVS operations, the visual glide slope 

indicator (VGSI) lights cannot be used as a visual reference, and specific visual 

references from both the threshold and TDZ must be distinctly visible and identifiable

to descend from DA/DH or MDA down to 100 feet above the TDZE. Under 

§ 91.175(c)(3) where natural vision is used to descend from DA/DH or MDA down to 

100 feet above the TDZE, however, only one of the specified visual references must be 

visible and identifiable.

3.1.5.3. At 100 feet above the TDZE of the runway of intended landing and below that altitude, 

the flight visibility using natural vision must be sufficient for one of the following 

visual references specified in § 91.176(b)(3)(iii) to be distinctly visible and identifiable 

to the pilot without reliance on the EFVS to continue to a landing:

1. The runway threshold; 

2. The lights or markings of the threshold; 

3. The runway touchdown zone landing surface; or 
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4. The lights or markings of the touchdown zone.

3.1.5.4. As stated in Section 3.1.1.1, above, a pilot cannot continue to descend below 100 feet 

by relying solely on the EFVS sensor image to identify the required visual references. 

The regulations do not require the pilot to turn off or stow the EFVS, nor do they

require the pilot to remove the sensor image from the EFVS display to continue to a 

landing without reliance on the sensor image. As long as the pilot can see the required 

visual references that he or she would normally see through the HUD with natural 

vision, the regulatory requirement can be met. This enables the pilot to continue to 

benefit from the HUD guidance and the additional situation and position awareness 

provided by the sensor image on the EFVS display. However, the pilot must base the 

decision to continue descending below 100 feet above the TDZE solely on seeing the 

required visual references through the EFVS display by means of natural vision. Table 1

contains a list of the visual references the FAA requires the pilot to see to descend 

below DA/DH or MDA and 100 feet above the TDZE using both natural vision and 

EFVS.

Table 1 Required Visual References

Required Visual References Using

Natural Vision

Required Visual References Using an 

Enhanced Flight Vision System

Descent below DA/DH or MDA under 14 

CFR § 91.175 (c) –

At least one of the following references using 

natural vision: 

Approach light system 

Threshold 

Threshold markings 

Threshold lights 

Runway end identifier lights 

Visual approach slope indicator 

Touchdown zone 

Touchdown zone markings 

Touchdown zone lights 

Runway 

Runway markings 

Runway lights

Descent below DA/DH or MDA under 14 CFR § 91.176 (a) 

or (b) –

The following references, using the EFVS: 

Approach light system 

OR

BOTH paragraphs A and B --

A. The runway threshold, identified by at least one of the 

following –

 -- beginning of the runway landing surface, 

 -- threshold lights, or 

 -- runway end identifier lights 

AND 

B. The touchdown zone, identified by at least one of the 

following –

 -- runway touchdown zone landing surface, 

 -- touchdown zone lights, 

 -- touchdown zone markings, or 

 -- runway lights.
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3.1.6. When to Go Around.

3.1.6.1. During an EFVS I operation, a pilot must initiate a missed approach at or below DA/DH

or MDA whenever:

1. The enhanced flight visibility from DA/DH or MDA down to 100 feet above the 

TDZE is less than the visibility minima prescribed for the IAP being used;

2. The required visual references for the runway of intended landing are no longer 

distinctly visible and identifiable to the pilot using the EFVS imagery;

3. The aircraft is not continuously in a position from which a pilot can make a descent 

to a landing on the intended runway, at a normal rate of descent, using normal 

maneuvers; 

4. The descent rate of the aircraft would not allow touchdown to occur within the TDZ 

of the runway of intended landing for operations conducted under Part 121 or 135;

5. Required equipment malfunctions or becomes inoperative; or

6. An aircraft equipment malfunction, other than required equipment, precludes the 

safe continuation of the EFVS I operation.

3.1.7. Other Operating Requirements for EFVS I Operations.

3.1.7.1. To conduct an EFVS I operation, the aircraft must be equipped with, and the pilot flying 

must use, an operable EFVS that meets the equipment requirements specified in 

§ 91.176(b)(1) and described in Section 3.1.2. While many EFVS-equipped aircraft 

provide a display of the sensor imagery to the pilot monitoring, U.S. regulations do not 

require it for EFVS I operations. When a display of the sensor imagery is not provided 

to the pilot monitoring during EFVS I operations, the FAA considers it sufficient to 

At and below 100 feet above the TDZE

under 14 CFR § 91.175 (c) –

At least one of the following visual references: 

Approach light system, as long as the red 

terminating bars or red side row bars are also 

distinctly visible and identifiable 

Threshold 

Threshold markings 

Threshold lights 

Runway end identifier lights 

Visual approach slope indicator 

Touchdown zone 

Touchdown zone markings 

Touchdown zone lights 

Runway 

Runway markings 

Runway lights

At and below 100 feet above the TDZE under 14 CFR §

91.176 (a) or (b) –

At least one of the following visual references using natural 

vision for EFVS I operations or using an EFVS for EFVS II 

operations:

The runway threshold,

The lights or markings of the threshold,

The runway touchdown zone landing surface, or

The lights or markings of the touchdown zone.
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conduct these operations using EFVS-specific procedures and callouts that support crew 

coordination and common situation awareness. At 100 feet above the TDZE, both pilots 

are relying on natural vision to identify the required visual references to descend to a 

landing. If the aircraft is equipped with a display of sensor imagery for the pilot 

monitoring, however, an operator should develop procedures for using the display and 

the pilot monitoring should receive training on how to use the display.

3.1.7.2. It is important that pilots possess the skills necessary to operate EFVS equipment, that 

they receive training, and that the training they receive supports the EFVS operation to 

be conducted. As a result, § 91.176(b)(2) specifies that each required pilot flight 

crewmember must have adequate knowledge of, and familiarity with, the aircraft, the 

EFVS, and the procedures to be used. Each required pilot flight crewmember also must 

meet the applicable training, recent flight experience, and proficiency requirements of 

§§ 61.31(l), 61.57(h), and 61.57(i) for EFVS operations. These requirements are

described in Sections 5 and 6. Parts 119 and 125 certificate holders must, in addition to 

the Part 61 requirements for EFVS operations, meet the applicable training, testing, and 

qualification provisions of Parts 121, 125, and 135, as applicable. For foreign persons 

conducting EFVS operations in the United States, each required pilot flight 

crewmember must meet the applicable training, recent flight experience, and 

proficiency requirements for EFVS operations of the civil aviation authority of the State 

of the Operator. Sections 5 and 6 address pilot training, recent flight experience, and 

proficiency requirements in more detail.

3.1.7.3. The FAA requires an authorization for persons conducting EFVS I operations under 

Part 91, subpart K, and Parts 121, 125, 129, and 135. A person who conducts these 

operations under Part 91, subpart K must do so in accordance with Management 

Specifications (MSpecs) authorizing the use of EFVS. Persons who conduct EFVS I 

operations under Part 121, 129, or 135 must do so in accordance with Operations 

Specifications (OpSpecs) authorizing the use of EFVS. A person who conducts EFVS I

operations under Part 125 must do so in accordance with OpSpecs authorizing the use 

of EFVS, or in the case of a Part 125 Letter of Deviation Authority (LODA) holder, an 

LOA for the use of EFVS. The FAA does not require Part 91 operators (other than Part 

91, subpart K operators) to obtain an LOA to conduct EFVS I operations. Section 10 

addresses authorization and operational approval requirements in more detail.

3.2. EFVS II Operations (§ 91.176(a)).

3.2.1. Operational Concept for EFVS II Operations.

3.2.1.1. You can find the regulations pertaining to EFVS II operations in § 91.176(a). Under 

§ 91.175(c) and § 91.176(a), there are two means of operating visually below DA/DH in 

the visual segment of an IAP. One means is by using natural vision under § 91.175(c), 

and the other is by using enhanced vision provided by an EFVS under § 91.176(a). An 

EFVS II operation is an operation in which the pilot uses the enhanced vision imagery 

provided by an EFVS in lieu of natural vision to descend below DA/DH to touchdown 

in reported visibility conditions as low as RVR 1000 feet on certain IAPs (see Figure 5). 
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To use an EFVS to descend below DA/DH, the pilot must meet certain enhanced flight 

visibility, visual reference, and operating requirements.

3.2.1.2. Section 91.176(a) permits a pilot to use an EFVS to identify the required visual 

references and to determine that the enhanced flight visibility provided by the EFVS is 

not less than the visibility prescribed in the IAP the pilot is flying. The pilot must meet 

both the visual reference and enhanced flight visibility requirements before the pilot can 

descend below DA/DH to touchdown. Sections 3.2.4 and 3.2.5 discuss enhanced flight 

visibility and required visual references, respectively, for EFVS II operations. In 

addition to the visual reference and enhanced flight visibility requirements, the 

regulations require that the aircraft be continuously in a position from which a pilot can

descend to a landing on the intended runway at a normal rate of descent using normal 

maneuvers. Additionally, for EFVS II operations conducted under Part 91, 121, 125, or 

135, the descent rate must allow touchdown to occur within the TDZ of the runway of 

intended landing. This differs from the regulatory requirement applicable to EFVS I 

operations. Only persons conducting EFVS I operations under Part 121 or 135 are 

required to touch down in the TDZ. The FAA considers it prudent to require all 

operators who conduct EFVS II operations to land within the TDZ to minimize any

potential for runway overrun in low-visibility conditions.

3.2.1.3. It is important to understand that using an EFVS does not result in obtaining lower 

minima with respect to the visibility specified in the IAP or the DA/DH. An EFVS 

simply provides another means, other than that of natural vision, of operating in the 

visual segment of an IAP. For example, a pilot conducting an EFVS II operation on a 

CAT I ILS approach that specifies a DA of 200 feet and a required visibility of 1⁄2 

statute mile (SM) must comply with a 200-foot DA and an enhanced flight visibility of 

1⁄2 SM, even though the pilot may not have 1⁄2 SM mile flight visibility using natural 

vision or 1⁄2 SM reported visibility. The fact that the pilot can use an EFVS in lieu of 

natural vision to descend below the DA to touchdown when the reported visibility is not 

less than RVR 1000 feet does not lower the DA or the visibility minima specified by

the IAP. The DA is still at 200 feet in this example, and the visibility requirement is still 

1⁄2 SM. The difference is whether the pilot assesses the 1⁄2 SM visibility prescribed by the 

IAP using natural vision or whether the pilot assesses it using an EFVS. People often 

misinterpret the benefit of EFVS by thinking it provides a lower decision altitude of 100 

feet. This is not correct. The decision altitude is specified by the IAP the pilot is flying, 

and it does not change whether EFVS is used or not. The 100-foot altitude is simply an

altitude along the approach path where a different set of visual references must be seen 

to continue descending to touchdown. What EFVS does, is give the pilot another means, 

other than using natural vision, to operate below decision altitude. Specifically, it gives 

the pilot another means to distinctly see and identify the required visual references 

when he or she might not be able to do so using natural vision, and it gives the pilot a 

means to see forward along the flightpath the distance required by the IAP -- called 

enhanced flight visibility – when the pilot might not be able to do so with natural vision. 

3.2.1.4. The FAA authorizes pilots to conduct EFVS II operations from DA/DH to touchdown 

down to a reported visibility of RVR 1000 feet. If RVR is not reported, then the lowest 

visibility at which a pilot can conduct an EFVS II operation is 1⁄4 SM, since a statute 
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mile visibility equivalent to RVR 1000 feet is not reported. The lowest specific 

visibility value reported through Automated Surface Observing System (ASOS), 

Automated Weather Sensor System (AWSS), or Automated Weather Observing System

(AWOS) is 1⁄4 SM. ASOS, AWSS, and AWOS report visibility values lower than 1⁄4 SM 

as “less than 1⁄4 SM,” except at certain locations where the service level provides 

additional visibility increments of 1/8, 1/16, and 0.

Figure 5 EFVS II Operational Concept

3.2.2. Equipment Requirements for EFVS II Operations.

3.2.2.1. An EFVS installed on a U.S.–registered aircraft that is used to conduct an EFVS II

operation must be operable and must be installed in accordance with an FAA-type 

design approval (a TC, ATC, or STC). A field approval is not an acceptable means of 

EFVS installation for operations conducted under § 91.176(a). A foreign-registered 

aircraft used to conduct EFVS operations that does not have an FAA-type design 

approval must be equipped with an operable EFVS that otherwise meets the 

requirements of the U.S. regulations.

3.2.2.2. An EFVS used to conduct EFVS II operations is an installed system that includes: 

 The display element, which is a HUD or an equivalent display, that presents the 

aircraft flight information, features, and characteristics required by the regulations 

such that they are clearly visible to the pilot flying in his or her normal position 

and line of vision looking forward along the flight path. An HDD does not meet 

the regulatory requirement for the display element because it is not a head-up 

presentation that permits the pilot to see the EFVS sensor imagery and aircraft 

flight symbology while seated in his or her normal position and line of vision 

looking forward along the flight path. The regulations do make provision, 

however, for head-up presentations, other than a HUD, that the FAA might find 

acceptable;

 Sensors that provide a real-time image of the forward external scene topography;

 Computers and power supplies;

 Indications; and 
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 Controls.

3.2.2.3. At a minimum, the EFVS must display the following specific aircraft flight information: 

 Airspeed;

 Vertical speed;

 Aircraft attitude;

 Heading;

 Altitude;

 Command guidance as appropriate for the approach to be flown;

 Path deviation indications;

 Flight path vector (FPV) cue;

 Flight path angle reference cue (FPARC);

 Height above ground level such as that provided by a radio altimeter or another 

device capable of providing equivalent performance. While the DA and 100-foot 

decision points on a precision IAP (other than those where a DH is specified) and 

an approach with approved vertical guidance are based upon barometric altitude, 

the supplementary information provided by a radio altimeter below 100 feet 

contributes to altitude awareness and can be used to help perform the flare and 

landing during EFVS II operations conducted to touchdown and rollout. While 

this is not a requirement for EFVS I operations, most aircraft used to conduct 

EFVS I operations have a radio altimeter; and

 Flare prompt or flare guidance, as appropriate, for achieving acceptable 

touchdown performance. Each applicant for type design approval would be 

required to demonstrate acceptable touchdown performance for their particular 

EFVS implementation using either flare prompt or flare guidance. This 

requirement is necessary to provide the pilot with additional information to 

conduct the flare maneuver during conditions of low visibility typically 

encountered during EFVS II operations to touchdown and rollout. Flare prompt 

or flare guidance is not required for EFVS I operations; however, an EFVS used 

to conduct EFVS I operations must be able to demonstrate acceptable touchdown 

performance.

3.2.2.4. When a minimum flightcrew of more than one pilot is required, the aircraft must be 

equipped with a display that provides the pilot monitoring with EFVS sensor imagery. 

The pilot monitoring display can be a HUD or an HDD. If it is a HUD, it can be a dualEFVS installation, a head mounted display, or other head up presentation the FAA 

might find acceptable. If it is an HDD, it must be located within the maximum primary

field of view of the pilot monitoring and any aircraft flight information or symbology

displayed must not adversely obscure the sensor imagery of the runway environment.

While this is a requirement for EFVS II operations, it is not a requirement for EFVS I 

operations. Many aircraft used for EFVS I operations, however, provide a display of the 

sensor imagery to the pilot monitoring.

3.2.2.5. The regulations also specify that the EFVS imagery, attitude symbology, FPV, FPARC, 

and other cues that are referenced to the imagery and external scene topography must be 
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conformal. That is, they must be aligned with and scaled to the external view. In 

addition, the EFVS must display the FPARC with the pitch scale, and the pilot must be 

able to select the appropriate descent angle for the approach. The EFVS must display

the sensor imagery and aircraft flight symbology such that they do not adversely

obscure the pilot’s outside view or field of view through the cockpit window. Finally, 

the display characteristics and dynamics must be suitable for manual control of the 

aircraft.

3.2.2.6. An EFVS that meets the certification criteria for EFVS II can also be used to conduct 

EFVS I operations.

3.2.2.7. The AFM or AFMS that the FAA approved for the aircraft must contain EFVS 

provisions appropriate to the EFVS operations to be conducted. An EFVS that the FAA

certified after (insert date of final rule) will contain all of the following statements for 

EFVS I operations:

 “The installed EFVS has been demonstrated to meet the criteria specified in AC 

20-167A for EFVS II to be used for instrument approach and landing operations 

that rely on sufficient visibility conditions to enable unaided rollout and to 

mitigate for loss of EFVS function. An EFVS that meets the certification criteria 

for EFVS II also meets the certification criteria for EFVS I.” and

 “During certification flight test, the lowest visibility and the maximum final 

approach course offset angle at which the installed EFVS was demonstrated to be 

used in lieu of natural vision to descend below DA/DH or MDA and complete a 

landing in accordance with 14 CFR § 91.176(b) was<insert RVR value or SM 

value> and <insert angle in degrees>, respectively.”
07/26/13 AC 90-106A

23

3.2.2.8. In addition to the statements described in Section 3.2.2.7, an AFM/AFMS may contain 

additional operating conditions and limitations that are applicable to the installed EFVS 

equipment.

3.2.3. Approaches Approved for EFVS II Operations.

3.2.3.1. A pilot may conduct an EFVS II operation on a straight-in precision IAP or an approach 

with approved vertical guidance, provided the pilot meets all of the requirements of the 

regulations (§§ 91.176, 121.651, 125.381, and 135.225, as appropriate). To ensure 

obstacle clearance and stabilized approach to touchdown, the approach must have 

published straight-in minima, a published vertical path, and a published DA, DH, or 

alert height (AH). This includes straight-in precision approaches such as ILS (CAT I, II, 

and III), MLS, PAR, and GLS, and straight-in approaches with published vertical 

guidance such as LPV and LNAV/VNAV. The FAA does not permit EFVS II 

operations on nonprecision approaches.

(Note: While § 91.189 and existing operational approval processes for CAT II 

and III operations could permit an appropriately certified EFVS to be used as 

part of these operations, criteria for using an EFVS for other than situation 

awareness on a CAT II or CAT III IAP has not yet been developed.)

3.2.3.2. An instrument approach with a circle-to-land maneuver or circle-to-land minimums 

does not meet the criteria for straight-in landing minimums. While the regulations do 

not prohibit a pilot from using EFVS during any phase of flight, they do prohibit a pilot 

from using it in lieu of natural vision to descend below DA/DH or MDA on anything 

but a straight-in IAP with straight-in landing minima. A pilot may only use EFVS 

during a circle-to-land maneuver provided the visual references required throughout the 

circling maneuver are distinctly visible using natural vision. An EFVS may not be used 

to satisfy the § 91.175(e)(2) requirement that an identifiable part of the airport be 

distinctly visible to the pilot during a circling maneuver at or above MDA or while 

descending below MDA from a circling maneuver. The pilot must accomplish this

using natural vision.

3.2.4. Enhanced Flight Visibility Requirements for EFVS II Operations.

3.2.4.1. For EFVS II operations conducted under §§ 91.176, 121.651, 125.381, and 135.225, the 

regulations state that no pilot may operate an aircraft at any airport below the authorized 

DA/DH and land unless the pilot determines that the enhanced flight visibility observed 

by use of a certified EFVS is not less than the visibility prescribed in the IAP being 

used. The EFVS requirements for enhanced flight visibility under § 91.176(a) are 

analogous to the flight visibility requirements for natural vision under § 91.175(c). To 

descend below DA/DH using natural vision under § 91.175(c), a pilot must make a 

determination that the flight visibility observed from the cockpit is not less than what is 

prescribed in the IAP the pilot is flying. The same is true for EFVS. Under § 91.176(a), 

a pilot must make a determination that the enhanced flight visibility observed by using 

an EFVS is not less than what is prescribed in the IAP the pilot is flying before 

descending below DA/DH to touchdown. Essentially, a pilot must accomplish the same
07/26/13 AC 90-106A

24

basic tasks before descending below DA/DH using EFVS that he or she would using 

natural vision to conduct an approach under § 91.175(c) – assess that the “enhanced”

flight visibility is not less than that specified in the IAP the pilot is flying, identify the 

required visual references for descent below DA/DH, assure the aircraft is continuously

in a position to land on the intended runway at a normal rate of descent using normal 

maneuvers, and for all operators, assure that the descent rate will allow touchdown to 

occur within the TDZ.

3.2.4.2. It is important to understand that, for a prescribed visibility value, the “sight picture” of 

the relevant visual references that the pilot can see looking forward along the flight path 

from the cockpit should be similar whether the pilot is using natural vision or an EFVS. 

An EFVS often produces the enhanced flight visibility prescribed by an IAP when 

actual reported visibility is much less. The point of this discussion is that even though 

actual visibility may be less, as long as the EFVS provides the required enhanced flight 

visibility and a pilot meets all of the other requirements of the regulations, the pilot can 

continue descending below DA/DH to touchdown and rollout using the EFVS. It is 

important that pilots receive training on how to assess enhanced flight visibility and 

what the “sight picture” should look like. How much of the forward scene, consisting of 

the ALS or other elements, a pilot sees at DA/DH under prescribed visibility conditions 

depends on individual IAP construction (geometry, threshold crossing height, slant 

range distance from the cockpit to relevant visual references, etc.), cockpit cutoff angle, 

and other relevant factors. As visibility conditions decrease, the ability of an EFVS to 

“see through” those conditions may also decrease. Under low or deteriorating visibility

conditions, the ability to properly assess whether the required enhanced flight visibility

exists to continue an approach becomes even more critical. The purpose of this 

discussion is not to suggest that a pilot should count approach lights to determine that 

the enhanced flight visibility is not less than what the IAP prescribes. Rather, it is to 

emphasize that through proper training, a pilot can learn to form a quick mental 

representation of what the visual scene should look like. In this example, the pilot 

should be able to see slightly further than the 1000-foot bar on the MALSR. If the pilot 

sees less than this, the required enhanced flight visibility does not exist for this example 

approach and the pilot should execute a missed approach. It is important to remember 

that the sight picture will vary depending on what type of approach lighting system is 

present, Figure 3 and Figure 4 show an example “sight picture” of what a pilot might 

expect to see upon arrival at a 200-foot DA with a flight visibility of RVR 2400 feet on 

a 3-degree GS.

3.2.5. Visual Reference Requirements for EFVS II Operations.

3.2.5.1. To descend below DA/DH, the following visual references specified in 

§ 91.176(a)(3)(ii) for the runway of intended landing must be distinctly visible and 

identifiable to the pilot using the EFVS:

1. The approach light system (if installed); or 

2. The following visual references in both 2(a) AND 2(b) below:
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25

a. The runway threshold, identified by at least one of the following: 

 The beginning of the runway landing surface;

 The threshold lights; or 

 The runway end identifier lights.

b. The touchdown zone, identified by at least one of the following: 

 The runway touchdown zone landing surface;

 The touchdown zone lights;

 The touchdown zone markings; or 

 The runway lights.

3.2.5.2. The main differences between the visual reference requirements for an approach using 

natural vision and one using EFVS are that, for EFVS operations, the VGSI lights 

cannot be used as a visual reference, and the pilot must be able to distinctly see and 

identify specific visual references from both the threshold and TDZ to descend from 

DA/DH or MDA down to 100 feet above the TDZE. Under § 91.175(c)(3) where 

natural vision is used to descend from DA/DH or MDA down to 100 feet above the 

TDZE, however, the pilot must be able to distinctly see and identify only one of the 

specified visual references.

3.2.5.3. At 100 feet above the TDZE of the runway of intended landing and below that altitude, 

the pilot using EFVS must be able to distinctly see and identify one of the following 

visual references specified in § 91.176(a)(3)(iii) –

1. The runway threshold; 

2. The lights or markings of the threshold; 

3. The runway touchdown zone landing surface; or 

4. The lights or markings of the touchdown zone.

3.2.5.4. A pilot who uses an EFVS that is certified for EFVS II operations can continue to 

descend below 100 feet relying solely on the EFVS sensor image to identify the 

required visual references provided the enhanced flight visibility requirements for 

descending below DA/DH to touchdown and rollout continue to be met and the other 

operating requirements of § 91.176(a) are met. In contrast to an EFVS I operation, no 

transition to natural vision is required at 100 feet above the TDZE. Table 1 contains a 

list of the visual references the pilot must see to descend below DA/DH and 100 feet 

above the TDZE using both natural vision and EFVS.

3.2.6. When to Go Around.

3.2.6.1. The regulatory requirements for when a pilot must execute a missed approach under 

§ 91.175(c), using natural vision, and § 91.176, using EFVS, are different. While these 

two sets of requirements provide a parallel decisionmaking process, the requirements 
07/26/13 AC 90-106A

26

for when a pilot must execute a missed approach differ. During an EFVS II operation, a 

pilot must initiate a missed approach at or below DA/DH whenever: 

1. The reported visibility is less than that specified in the operator’s OpSpec, MSpec, 

or LOA;

2. The enhanced flight visibility required to descend below DA/DH is less than the 

visibility minima prescribed for the IAP the pilot is flying;

3. The required visual references for the runway of intended landing are no longer 

distinctly visible and identifiable to the pilot using the EFVS imagery;

4. The aircraft is not continuously in a position from which a descent to a landing can 

be made on the intended runway, at a normal rate of descent, using normal 

maneuvers; 

5. The descent rate of the aircraft would not allow touchdown to occur within the TDZ

of the runway of intended landing;

6. Required equipment malfunctions or becomes inoperative; or

7. An aircraft equipment malfunction, other than required equipment, precludes the 

safe continuation of the EFVS II operation.

3.2.7. Other Operating Requirements for EFVS II Operations.

3.2.7.1. To conduct an EFVS II operation, the aircraft must be equipped with, and the pilot 

flying must use, an operable EFVS that meets the equipment requirements specified in 

§ 91.176(a)(1). When a minimum flightcrew of more than one pilot is required, 

§ 91.176(a)(2)(iii) requires the pilot monitoring to use a display that provides EFVS 

sensor imagery to monitor and assess the safe conduct of the approach, landing, and 

rollout. During EFVS operations where the pilot flying relies on EFVS from DA/DH 

through touchdown and rollout, one cannot assume that the monitoring pilot sees 

anything of the outside environment using natural vision. Providing the pilot monitoring 

with a display of EFVS sensor imagery supports that pilot’s view of the outside 

environment and provides common situation awareness. The pilot monitoring would 

carry out his or her normal approach monitoring tasks and use the display of EFVS 

sensor imagery to confirm the required visual references, verify visual acquisition of 

and alignment with the runway of intended landing, and assist in determining that the 

runway is clear of aircraft, vehicles, or other obstructions. Section 3.2.2.4 discusses the 

requirements applicable to the pilot monitoring display.

3.2.7.2. It is important that pilots possess the skills necessary to operate EFVS equipment, that 

they receive training, and that the training they receive supports the EFVS operation to 

be conducted. As a result, § 91.176(a)(2) specifies that each required pilot flight 

crewmember must have adequate knowledge of, and familiarity with, the aircraft, the 

EFVS, and the procedures to be used. Each required pilot flight crewmember also must 

meet the applicable training, recent flight experience, and proficiency requirements of 
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27

§§ 61.31(l), 61.57(h), and 61.57(i) for EFVS operations. Parts 119 and 125 certificate 

holders must, in addition to the part 61 requirements for EFVS operations, meet the 

applicable training, testing, and qualification provisions of parts 121, 125, and 135, as 

applicable. For foreign persons conducting EFVS operations in the United States, each 

required pilot flight crewmember must meet the applicable training, recent flight 

experience, and proficiency requirements for EFVS operations of the civil aviation 

authority of the State of the Operator. Sections 5 and 6 address training, recent flight 

experience, and proficiency requirements in more detail.

3.2.7.3. The FAA requires an authorization for all persons conducting EFVS II operations under 

Parts 91, 121, 125, 129, and 135. A person who conducts EFVS II operations under Part 

91 (other than Part 91, subpart K) must do so in accordance with an LOA for EFVS II 

operations. A person conducting EFVS II operations under Part 91, subpart K must 

conduct them in accordance with MSpecs authorizing the use of EFVS. Persons who 

conduct EFVS II operations under Parts 121, 129, or 135 must do so in accordance with 

OpSpecs authorizing the use of EFVS. A person who conducts EFVS II operations 

under Part 125 must do so in accordance with OpSpecs authorizing the use of EFVS, or 

in the case of a Part 125 LODA holder, an LOA for the use of EFVS. Section 10

addresses authorization and operational approval requirements in more detail.

3.2.8. Example Approaches using EFVS.

3.2.8.1. In the instrument segment of an IAP, which extends down to DA/DH or MDA, a pilot’s 

primary reference for maneuvering the aircraft is based on aircraft instruments, 

displays, and onboard navigation system. In the instrument segment, an EFVS provides 

supporting information and enhances a pilot’s situation awareness by providing a realtime image of the external scene. In the visual segment of an IAP, which extends from 

DA/DH or MDA down to the runway, a pilot’s primary reference for maneuvering the 

aircraft is based on what he or she sees using natural vision, or in the case of an EFVS 

operation, what he or she sees using the EFVS. In the visual segment, the aircraft 

instruments, displays, and onboard navigation system provide supporting information.

The visual information provided by an EFVS serves as independent verification of the 

position information provided by the aircraft’s displays and systems. The visual 

information provided by an EFVS also contributes to assessing the enhanced flight 

visibility, helps a pilot align the aircraft with the runway, and provides position, lateral 

roll, rate of closure, and distance remaining information.

3.2.8.2. Figure 6 provides an example of how a pilot might use an EFVS on a straight-in 

precision approach and includes distances from relevant points along the flight path. For 

a CAT I ILS approach, pilots should be aware that the CAT I GS signal is typically only 

flight inspected to 100 feet to support published minimums as low as 200 feet above the 

threshold. The localizer signal is only flight inspected for CAT I certification purposes 

to the missed approach point (MAP). Though many localizers provide acceptable 

guidance on the runway, the necessary localizer critical area to ensure signal integrity is 

not maintained for CAT I ILS operations. For ILS critical area limitations, pilots should 

refer to the Aeronautical Information Manual (AIM) paragraphs in Chapter 1, Section 1, 
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28

titled “Instrument Landing System (ILS),” and the paragraphs in Chapter 2, Section 3, 

titled “Mandatory Instruction Signs” and “Location Signs.”

Figure 6 Use of EFVS on a Precision Approach

3.2.8.3. Figure 7 provides an example of how a pilot might use an EFVS on a straight-in

approach with published vertical guidance and includes distances from relevant points 

along the flight path. The descent angle shown on the approach plate depicts a 

computed vertical path from the Final Approach Fix (FAF) to the runway threshold at 

the published threshold crossing height (TCH). By using this published vertical path, 

the pilot maintains a stabilized approach that ensures obstacle clearance.

Figure 7 Use of EFVS on an Approach With Approved (Published) Vertical Guidance
07/26/13 AC 90-106A

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3.2.8.4. Figure 8 provides an example of how a pilot might use an EFVS on a straight-in 

nonprecision approach and includes distances from relevant points along the flight path. 

When VNAV is not available, a pilot may use other methods for achieving a constant 

rate of descent, such as using a self-computed descent rate or using an FPARC and FPV 

cue to fly a vertical path that safely clears obstacles. On a nonprecision approach, it is 

the pilot’s responsibility to determine a safe path to the runway that clears obstacles. A 

pilot who conducts a straight-in nonprecision approach should also verify lateral 

alignment with the runway centerline before descending from the MDA because actual 

lateral course alignment can vary depending upon facility type, distance from the 

facility, or signal variations that can cause an offset from the intended course centerline.

Figure 8 Use of EFVS on a Nonprecision Approach
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3.3. Considerations for EFVS I and EFVS II Operations.

3.3.1. EFVS Sensor Performance.

3.3.1.1. During some reduced-visibility conditions, an EFVS can display imagery that may

significantly improve the pilot’s capability to detect approach lights and visual 

references of the runway environment and aircraft, vehicles, and animals encroaching 

on the landing runway that may not otherwise be visible using natural vision. Pilots 

using an EFVS should be careful not to conclude that the flight path is free of hazards 

merely because no hazards are visible in the image. In some situations, imaging sensor 

performance can be variable and unpredictable. Additionally, to assure a safe obstacle 

clearance margin, certain nonprecision instrument approaches may require a pilot to 

visually identify known obstacles near the normal approach path when maneuvering in 

the visual phase for landing.

3.3.2. Stabilized Approach.

3.3.2.1. Controlled Flight Into Terrain (CFIT) is one of the primary causes of aviation fatal 

accidents worldwide. Unstabilized approaches are a key contributor to CFIT events. 

Nonprecision approach design may require pilots to perform one or more “step-downs” 

during the final approach segment, necessitating multiple thrust, pitch, and altitude 

adjustments inside the FAF, thereby increasing pilot workload and the potential for 

error during a critical phase of flight. Additionally, on approaches designed without 

“step-down” fixes, pilots may descend to the MDA immediately after the FAF. This 

practice, commonly referred to as “dive and drive,” can result in extended level flight as 

low as 250 feet above the obstacle environment in instrument meteorological conditions 

(IMC). The concept of a stabilized approach has been widely promoted for air carrier 

operators as a means to help eliminate approach and landing accidents. The goal is to 

have the aircraft in the proper landing configuration, at the proper approach speed, and 

on the proper flight path before descending below the minimum stabilized approach 

height. AC 120-71 considers minimum stabilized approach height to be 1000 feet above 

the airport elevation or TDZ Elevation (TDZE) during IMC. 

3.3.3. Offset Approaches. 

3.3.3.1. Criteria contained in the U.S. Standard for Terminal Instrument Procedures (TERPS) 

permits IAPs to be offset by prescribed amounts and still be considered straight-in with 

straight-in minima. A non-RNAV nonprecision approach, for example, can be offset up 

to 30 degrees from the runway centerline, cross the final approach course up to 5200 

feet from the runway threshold, be considered straight-in, and have straight-in minima. 

A GPS or RNAV (GPS) approach with LNAV or LNAV/VNAV minimums can be 

offset as much as 15 degrees and still be considered straight in, and an ILS or LPV 

approach can be offset as much as 3 degrees. Pilots must be especially knowledgeable 

of the approach conditions and approach course alignment when considering whether to 

rely on EFVS during a nonprecision approach with an offset final approach course. 

Depending upon the combination of crosswind correction, approach course offset, and 

the lateral field of view provided by a particular EFVS, the required visual references 
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31

may or may not be within the pilot’s view looking through the EFVS display upon 

reaching the missed approach point (MAP).

3.3.4. Visual Segment Obstacle Clearance.

3.3.4.1. Precision approaches (e.g., ILS/ MLS) or approaches with computed vertical paths (e.g., 

LNAV/VNAV, LPV, etc.) provide the highest level of safety for both obstacle 

clearance and controlled rate of descent. If there is no published vertical guidance to a 

runway, the use of the HUD’s FPV and FPARC may assist the pilot in safely flying a 

vertical path to clear all obstacles. Since the aircraft is in the visual segment of the 

approach, it is incumbent on the pilot to select an appropriate vertical path that ensures 

obstacle clearance.

3.3.4.2. The presence of a charted vertical descent angle (VDA) does not guarantee obstacle 

protection in the visual segment and does not change any of the requirements for flying

a nonprecision approach. The published VDA is for information only, and is strictly

advisory in nature. There is no implicit additional obstacle protection below the MDA. 

3.3.4.3. Additional protection for the visual segment below the MDA is provided if a vertical 

descent point (VDP) is published and descent below the MDA is started at or after the 

VDP. VDPs provide pilots with a reference for the optimal location to begin descent 

from the MDA, based on the designed VDA for the approach procedure, assuming the 

required visual references are available. Approaches without VDPs have not been 

assessed for terrain or obstacle clearance below the MDA, and may not provide a clear 

vertical path to the runway at the normally expected descent angle. Therefore, pilots 

must be especially vigilant when descending below the MDA at locations without 

VDPs. This does not necessarily prevent flying the normal angle; it only means that 

obstacle clearance in the visual segment could be less and pilots should exercise greater 

care in looking for and avoiding obstacles in the visual segment. 

3.3.4.4. The use of a VGSI can help the pilot determine if the aircraft is in a position to make a 

descent from the MDA. However, when the visibility is close to minimums, the VGSI

may not be visible at the start descent point for a normal glide path due to its location 

down the runway. Obstacle protection is provided if a VGSI (e.g., VASI or PAPI) is 

installed and the aircraft remains on the VGSI glide path angle from the MDA. In some 

cases, the VDA and VGSI angles are not coincident and a chart note will indicate that 

they are not coincident. In addition, depending on the visibility and the distance the 

aircraft is from the VGSI, the color of the VGSI lights might not be seen through the 

EFVS or through the HUD (without EFVS) using natural vision. Operators should be 

aware that light color can generally be seen through an EFVS when it can be seen 

through a HUD with natural vision because the HUD is transparent. 

3.3.4.5. Pilots should carefully review approach procedures, prior to initiating an approach, to 

identify the optimum position(s), and any unacceptable positions, from which a descent 

to landing can be initiated. One can find additional information with respect to obstacle 

clearance, VDA, and VDP in the AIM and the Instrument Procedures Handbook.
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3.3.5. Missed Approach Obstacle Clearance.

3.3.5.1. The published missed approach procedure provides obstacle clearance only when the 

missed approach is conducted on the missed approach segment from or above the 

missed approach point, and assumes a climb rate of 200 ft/NM or higher, as published. 

If the aircraft initiates a missed approach at a point other than the missed approach 

point, from below MDA or DA/DH, obstacle clearance is not necessarily provided by 

following the published missed approach procedure, nor is separation assured from 

other air traffic in the vicinity. 

3.3.5.2. Prior to initiating an IAP, the pilot should assess the actions to be taken in the event of a 

balked (rejected) landing beyond the missed approach point or below the MDA or 

DA/DH considering the anticipated weather conditions and available aircraft 

performance. Section 91.175(e) authorizes the pilot to fly an appropriate missed 

approach procedure that ensures obstruction clearance, but it does not necessarily

consider separation from other air traffic. The pilot must consider other factors such as 

the aircraft’s geographical location with respect to the prescribed missed approach 

point, direction of flight, and/or minimum turning altitudes in the prescribed missed 

approach procedure. The pilot must also consider aircraft performance, visual climb 

restrictions, charted obstacles, published obstacle departure procedures, takeoff visual 

climb requirements as expressed by nonstandard takeoff minima, other traffic expected 

to be in the vicinity, and other factors not specifically addressed by the approach 

procedures.

3.3.6. Light Emitting Diode (LED) Lighting.

3.3.6.1. The FAA has replaced incandescent lights with LEDs on certain obstacles and at certain 

airport locations throughout the United States. LEDs may also appear in taxiway

centerline lights, taxiway edge lights, low-intensity runway edge lights, beacons, and 

obstruction lights. The FAA also has future plans to replace incandescent lamps with 

LEDs in MALSRs and green threshold lamps. It is important for pilots to be aware that 

certain IR-based EFVS cannot sense, nor do they image, LEDs. The use of LEDs may

diminish the benefits of these EFVS systems, but they do not completely eliminate 

them. While the ability to sense approach lights enables EFVS to be used over a wider 

range of low-visibility conditions, EFVS also images the runway environment and 

runway markings, which are also visual references permitted to be used to descend 

below DA/DH or MDA. Future EFVS systems may utilize other sensor technologies 

that are not dependent on sensing light output, such as millimeter wave radar, or that are 

capable of imaging LEDs by other means. The FAA and industry are working together 

to resolve the current issues associated with EFVS and LED interoperability. 

3.3.7. Low-Visibility Operations and Surface Movement Guidance and Control System 

(LVO/SMGCS) Operations.

3.3.7.1. FAA Order 8000.94, Procedures for Establishing Airport Low-Visibility Operations 

and Approval of Low-Visibility Operations/Surface Movement Guidance and Control 

System Operations, provides policy for Low-Visibility Operations/Surface Movement 
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Guidance and Control System (LVO/SMGCS) operations at Part 139 airports in the 

United States. For the purposes of FAA Order 8000.94, LVO means those airport 

operations conducted at visibilities of less than RVR 1200. Order 8000.94 provides for 

consistent low-visibility (less than RVR 1200) airport operations, establishes standards

for low-visibility airport equipment and enhancements, and implements uniform air 

traffic control practices and expectations. Because operating in low-visibility conditions 

can be difficult, increased control over aircraft and ground vehicle movement is 

essential to protecting the runway from incursions during high-speed LVO. Over the 

years, the LVO/SMGCS program has proven to be an effective means of improving 

safety by increasing control over aircraft and ground vehicle movement during periods 

of low visibility. 

3.3.7.2. FAA Order 8000.94 describes two levels of LVO/SMGCS operations. One level begins 

at less than RVR 1200 and extends down to RVR 500. The second level begins at less 

than RVR 500 and extends down to RVR 300. The 500 RVR value which defines the 

transition between the two levels of LVO/SMGCS operations was recently changed 

from RVR 600 to RVR 500 by Order 8000.94. As a result, airports are are in the 

process of transitioning from RVR 600 to RVR 500. While each airport’s 

LVO/SMGCS plan may be different, each airport’s plan will specify their criteria for 

entering and exiting LVO/SMGCS operations, the applicable authorized RVR for 

ground movement, and the criteria for determining when the airport reaches the lowest 

approved LVO/SMGCS level. Based on those criteria, the air traffic control tower or 

other appointed air traffic facility specified in the LVO/SMGCS plan will determine 

when the airport starts and stops LVO/SMGCS operations. 

3.3.7.3. Any use of EFVS and other emerging technologies as a suitable substitute for 

established LVO/SMGCS requirements will undergo a specific FAA Headquarters 

review and approval to determine whether the proposed technology meets an FAAdetermined equivalent level of safety. If the FAA approves a proposed technology as a 

suitable substitute and approves the technology for use at a specific airport, the airport

will incorporate specific provisions for using that technology into their individual 

airport LVO/SMGCS plan.

3.3.7.4. Authorizations to conduct EFVS operations will require operators to comply with the

LVO/SMGCS plan at the airports they operate to. An operator who wishes to conduct 

an EFVS operation at an airport that has an LVO/SMGCS plan should be aware that

some taxiways and runways may not be available when LVO/SMGCS operations are in 

effect if those taxiways and runways are not specified for use in the airport’s 

LVO/SMGCS plan. Operators should receive training on the levels of LVO/SMGCS 

operations, procedures associated with LVO/SMGCS operations, and the lighting, 

marking, and signage requirements associated with those levels. You can find additional 

information on LVO/SMGCS operations in FAA Order 8000.94 and AC 120-57, 

Surface Movement Guidance and Control System. You can find FAA Airports design 

standards, system descriptions, and criteria for Part 139 airports in 150-series ACs.

3.3.8. International Operations.
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3.3.8.1. Currently, most foreign civil aviation authorities (CAAs) require an authorization to 

conduct EFVS operations. As a result, a foreign CAA may require a U.S. operator who 

wishes to conduct EFVS operations in their country to submit their FAA EFVS 

authorization as a condition for the foreign CAA’s approval. The FAA strongly 

recommends that operators contact the CAA of each foreign country in which they plan 

to conduct EFVS operations to determine the equipment requirements, operational 

approval requirements, and requirements for conducting EFVS operations, since those 

requirements may be different from those of the United States. Operators of U.S.-

registered civil aircraft outside of the United States are reminded that they must comply

with § 91.703 and other applicable regulations pertaining to operations that are 

conducted outside the United States. This results in complying with the U.S. regulations 

and the regulations of the country in which operations are being conducted, whichever 

is more restrictive.
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4. EFVS Operations When the Reported or Forecast Visibility at the Destination 

Airport is Below Authorized Minimums

4.1. Dispatch, Flight Release, or Takeoff Under IFR When the Reported or Forecast 

Visibility at the Destination Airport is Below Authorized Minimums.

4.1.1. The enhanced flight visibility provided by an EFVS enables a pilot to conduct instrument 

approach operations safely in lower visibilities than would be possible using natural 

vision. Under §§ 121.613, 121.615, 125.361, 125.363, and 135.219, operators of EFVSequipped aircraft are permitted to dispatch or release a flight under Part 121, release a 

flight under Part 125, or takeoff under IFR under part 135 when weather reports and 

forecasts indicate that weather conditions will be below the minimums authorized for the 

approaches the pilot will fly at the estimated time of arrival at the airport or airports to 

which dispatched or released. This enables operators to take advantage of the operational 

capabilities provided by EFVS and thus improve access to runways, increase service 

reliability, and reduce the costs associated with operational delays without compromising 

safety. These EFVS provisions apply only to destination airports and do not apply to 

alternate airports.

4.1.2. Operators of EFVS-equipped aircraft are authorized to dispatch, flight release, or takeoff 

under IFR when the weather conditions at the destination airport are reported or forecast

to be below authorized minimums at the estimated time of arrival through an OpSpec for 

EFVS operations conducted under Part 121, 125, or 135, or for Part 125 Letter of 

Deviation Authority (LODA) holders, their Letter of Authorization (LOA) for EFVS 

operations. The authorization applies to both EFVS I operations conducted under 

§ 91.176(b) and EFVS II operations conducted under § 91.176(a). The Principal 

Operations Inspector (POI) will develop OpSpec or LOA conditions and limitations 

based on the EFVS capabilities that were demonstrated for the aircraft during 

certification flight test and documented in the AFM or AFMS, additional data the 

operator may have collected through an operational evaluation with respect to the EFVS 

sensor’s ability to perform in low-visibility conditions, other rationale the FAA might 

find acceptable, and the operator’s ability to perform EFVS operations during the 

operational use suitability demonstration (OUSD) period which is part of the operational 

approval process. Section 4.2 discusses this in more detail. The purpose of developing 

these conditions and limitations is to ensure that an increase in the rate of missed 

approaches at the destination airport does not occur during EFVS operations. Because 

EFVS performance can vary by sensor technology and design, meteorological conditions, 

and other factors, the POI may make adjustments to an operator’s EFVS authorization if

the POI observes an increase in the number of missed approaches during an operator’s 

EFVS operations. Managing an authorization in this manner ensures that the FAA is able 

to maintain an appropriate level of safety, enables the FAA to effectively respond to new 

technology developments, and provides a means to tailor an authorization to fit an 

operator’s particular EFVS capabilities.

4.1.3. Operators who plan to conduct these operations should establish operating procedures,

pilot training, and training for dispatchers and persons authorized to exercise operational 

control under these conditions. The procedures and training should consider the 
07/26/13 AC 90-106A

36

limitations of the EFVS the operator will use and the weather conditions that may exceed 

the sensor’s ability to provide the enhanced flight visibility required to complete the 

approach and landing. Section 7 contains recommended training for dispatchers and other 

persons authorized to exercise operational control. Section 5 contains training 

requirements and recommendations for pilots.

4.2. Initiating or Continuing an Approach When the Destination Airport Visibility is 

Below Authorized Minimums.

4.2.1. Years of EFVS operational experience show that, under certain reduced-visibility

conditions, an EFVS can increase the likelihood that a pilot can successfully complete an 

approach and landing. In cases where the visibility is marginal, such as during rapidly 

changing weather conditions, or when the reported visibility hovers at or near the 

minimum authorized, natural vision may be inadequate for a pilot to detect the required 

visual references necessary to complete the approach. EFVS can provide a significant 

operational advantage under these circumstances by reducing ground stops, holding 

delays, and diversions to an alternate airport.

4.2.2. Under §§ 121.651, 125.325, 125.381, and 135.225, persons conducting operations under 

Part 121, 125, or 135 are permitted to initiate or to continue an approach when the 

reported visibility is below the authorized minimum visibility prescribed in the IAP the 

pilot will be flying, provided the aircraft is equipped with, and a properly trained pilot 

uses, an EFVS in accordance with § 91.176. This provision, combined with the dispatch, 

flight release, and takeoff provisions discussed in Section 4.1 enables operators of 

appropriately equipped EFVS aircraft to take full advantage of the operational 

capabilities provided by EFVS without compromising safety.

4.2.3. Operators of EFVS-equipped aircraft are authorized to initiate or to continue an approach 

when the reported visibility is below the authorized visibility minimums prescribed in the 

IAP through an OpSpec for EFVS operations conducted under Part 121, 125, or 135, or 

for Part 125 LODA holders, through their LOA for EFVS operations. The authorization 

applies to both EFVS I operations conducted under § 91.176(b) and EFVS II operations 

conducted under § 91.176(a).

4.2.4. Operators who plan to conduct EFVS operations should establish pilot procedures and 

training for initiating or continuing an approach when the reported visibility is below the 

authorized visibility minimums for the approach to be flown. Operators should also 

develop procedures and training for dispatchers or persons authorized to exercise 

operational control that address initiating or continuing an approach under the EFVS 

provisions of §§ 121.651, 125.325, 125.381, and 135.225. These procedures should

consider the limitations of the EFVS the operator will use and the weather conditions that 

exceed the sensor’s ability to provide the enhanced flight visibility required to complete 

the approach and landing. Section 7 contains recommended training for dispatchers and 

persons authorized to exercise operational control, and Section 5 contains required and 

recommended training for pilots.
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37

4.2.5. An operator’s POI will also develop OpSpec conditions and limitations for part 121, 125 

or 135 operators or LOA conditions and limitations for part 125 LODA holders for 

initiating or continuing an approach when the reported visibility is below the authorized 

minimum visibility prescribed in the IAP the pilot will fly. The POI will develop these 

conditions and limitations based on the EFVS capabilities that were demonstrated for the 

aircraft during certification flight test and documented in the AFM or AFMS, additional 

data the operator may have collected through an operational evaluation with respect to 

the EFVS sensor’s ability to perform in low-visibility conditions, other rationale the FAA 

might find acceptable, and the operator’s ability to perform EFVS operations during the 

OUSD period which is part of the operational approval process. The purpose of 

developing these conditions and limitations is to ensure that an increase in the rate of 

missed approaches at the destination airport does not occur during EFVS operations. 

Because EFVS performance can vary by sensor technology and design, meteorological 

conditions, and other factors, the POI may make adjustments to an operator’s EFVS

authorization if the POI observes an increase in the number of missed approaches during 

an operator’s EFVS operations. As discussed in Section 4.1, managing the authorization 

in this manner ensures that the FAA is able to maintain an appropriate level of safety, 

enables the FAA to effectively respond to new technology developments, and provides a 

means to tailor an authorization to fit an operator’s particular EFVS capabilities.

4.2.6. The operational goal of the EFVS provisions discussed in Sections 4.1 and 4.2 is to 

ensure that no more than 5 percent of the approaches conducted using EFVS during a

Part 121, 125, or 135 operation terminates in a missed approach due to the EFVS sensor’s 

inability to provide the enhanced flight visibility required to conduct the EFVS operation.

The OUSD will address these and other aspects of an operator’s EFVS operation and 

should be conducted over a combination of visibility conditions down to, and including, 

the lowest visibility for which the operator is seeking authorization. Inability to achieve 

this operational goal during the OUSD period may require an extended OUSD period 

while the POI and the operator work together to adjust the authorization so that it 

achieves this operational goal. The POI may also apply similar adjustments to an 

operator’s authorization for dispatch, flight release, or takeoff under IFR.

4.2.7. Pilots should be aware that some foreign Civil Aviation Authorities (CAAs) permit 

operators to deduct 1/3 of the visibility required by an IAP to initiate or continue an 

approach using an EFVS when the visibility is reported to be below minimums for the 

approach to be flown. For example, if the authorized minimum visibility for an IAP is 

RVR 2400 feet, a person operating an EFVS-equipped aircraft could reduce the minimum 

visibility required for an approach by 1/3, resulting in an adjusted required minimum 

visibility of RVR 1600 feet for the approach. Years of EFVS operations have shown this 

to be a valid approach that accommodates most EFVSs currently in use. The FAA 

strongly recommends that operators contact the CAA of each foreign country in which 

they plan to conduct EFVS operations to determine the requirements for conducting 

EFVS operations, since those requirements may be different from those of the United 

States.
07/26/13 AC 90-106A

38

5. Pilot Training Requirements for EFVS Operations

5.1. Regulatory Requirement for Training.

5.1.1. A pilot typically conducts EFVS operations in lower than standard visibility conditions. 

Over the years, EFVS operations have expanded, increasing the number and mix of 

aircraft and operators conducting low-visibility operations at airports throughout the 

national airspace system (NAS). Because of the conditions under which a pilot conducts 

EFVS operations, it is important that pilots possess the skills necessary to safely and 

effectively operate EFVS equipment and that the training they receive supports the EFVS 

operation they are conducting.

5.1.2. 14 CFR §§ 91.176(a)(2) and (b)(2) specify that no person may conduct an EFVS 

operation in an aircraft, except a military aircraft of the United States, at any airport 

below the authorized DA/DH or MDA for EFVS I operations or below DA/DH for EFVS 

II operations unless each required pilot flight crewmember has adequate knowledge of, 

and familiarity with, the aircraft, the EFVS, and the procedures the pilot will use. The 

regulations further state that each required pilot flight crewmember must also meet the 

applicable training, recent flight experience and proficiency requirements of §§ 61.31(l), 

61.57(h), and 61.57(i) for EFVS operations. In addition to the Part 61 requirements for 

EFVS operations, Part 119 and 125 certificate holders must meet the training, testing, and 

qualification provisions of Parts 121, 125, and 135, as applicable.

5.1.3. Pilot training shall be comprised of both ground and flight training that meets the 

requirements of § 61.31(l). In addition to the training guidance provided in this AC, 

operators and training providers should refer to the Flight Standardization Board (FSB)

report for the EFVS-equipped aircraft they will be flying, if such a report is available. 

The FAA Aircraft Evaluation Group (AEG) has conducted operational suitability

evaluations of EFVS equipment installed on certain aircraft and has documented through 

FSB reports areas for special emphasis in addition to the training, checking, and currency

tasks necessary to safely operate EFVS equipment. You can find FSB reports at

http://fsims.faa.gov/PICResults.aspx?mode=Publication&doctype=FSB%20Reports.

5.2. Initial Ground Training.

5.2.1. Sections 61.31(l)(1) and (2) contain the ground training requirements for EFVS I and 

EFVS II operations. Under § 61.31(l)(1), any person manipulating the controls of an 

aircraft or acting as pilot in command (PIC) of an aircraft during an EFVS operation must 

receive ground training from an authorized instructor under a training program approved

by the Administrator. The pilot must obtain a logbook or other endorsement from the

authorized instructor who certifies that he or she satisfactorily completed the ground 

training. These ground-training requirements apply to both EFVS I and EFVS II 

operations. You can find the definition of an “authorized instructor” in § 61.1(b)(2), and 

Section 5.7.1 of this AC explains what a “training program approved by the 

Administrator” means.
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39

5.2.2. The regulations also require any person who serves as a required pilot flight crewmember 

during an EFVS II operation, but who does not manipulate the controls or serve as PIC of 

that aircraft, to obtain ground training. An authorized instructor must conduct the ground 

training, and the ground training must be a training program that is approved by the 

Administrator. The required pilot flight crewmember must obtain a logbook or other 

endorsement from an authorized instructor who certifies that he or she satisfactorily 

completed the ground training.

5.2.3. 14 CFR § 61.31(l)(7) contains certain exceptions to the § 61.31(l)(1) ground training 

required to conduct EFVS operations. Section 5.4 explains these exceptions.

5.2.4. Under § 61.31(l), a person who serves as a required pilot flight crewmember during an 

EFVS I operation, but who does not manipulate the controls or serve as PIC of that 

aircraft, is not required to receive EFVS ground training. Pilots should be aware, 

however, that § 61.55 requires any person serving as second-in-command to be familiar 

with the operational procedures applicable to an aircraft’s powerplant; equipment and 

systems; performance specifications and limitations; normal, abnormal, and emergency

procedures; and flight manual, placards and markings. Part 61 contains the minimum 

training requirements for EFVS operations. In addition to the Part 61 requirements, pilots 

must also comply with the training provisions of the part under which they conduct flight 

operations. Part 121, for example, requires ground and flight training appropriate to the 

particular assignment of the pilot flight crewmember.

5.2.5. Ground training must, at a minimum, consist of the following subjects in accordance with 

§ 61.31(l)(2):

1. Applicable portions of 14 CFR that relate to EFVS flight operations and limitations, 

including AFM limitations;

2. EFVS display, controls, modes, features, symbology, annunciations, and associated 

systems and components;

3. EFVS sensor performance, sensor limitations, scene interpretation, visual anomalies, 

and other visual effects;

4. Preflight planning and operational considerations associated with using EFVS during 

taxi, takeoff, climb, cruise, descent, and landing phases of flight, including the use of 

EFVS for instrument approaches, operating below DA/DH or MDA, executing 

missed approaches, landing, rollout, and balked landings;

5. Weather associated with low-visibility conditions and its effect on EFVS 

performance;

6. Normal, abnormal, emergency, and crew coordination procedures when using EFVS;

and

7. Interpretation of approach and runway lighting systems and their display 

characteristics when using an EFVS.
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40

5.2.6. For certain ground training requirements listed in Section 5.2.5, the FAA recommends 

that the ground training cover the following additional subject areas:

1. Applicable portions of 14 CFR that relate to EFVS flight operations and limitations, 

including AFM limitations:

a. Regulatory requirements pertinent to the operation being conducted (e.g., 

§§ 61.31(l), 61.57(h) and (i), 91.175(d)(1), 91.175(e)(1), 91.176, 91.189(d), 

121.613, 121.615(a), 121.651, 125.325, 125.361, 125.363(a), 125.381, 135.219, 

and 135.225). With respect to § 91.189(d), pilots should note that criteria for 

using EFVS on CAT II or CAT III approaches has not yet been developed;

b. Enhanced flight visibility requirements (§ 91.176);

c. Visual reference requirements (§ 91.176); and

d. AFM or AFMS limitations.

2. EFVS display, controls, modes, features, symbology, annunciations, and associated 

systems and components accompanied by a review of the AFM or AFMS sections 

that relate to EFVS, including system description, operating procedures and 

limitations:

a. Use of on/off switch “clear” mode;

b. Warm-up requirements, system alignment, display adjustments for brightness and 

contrast, contrast differences between daytime and nighttime approach conditions 

and display field of view;

c. Understanding and interpreting HUD symbology during EFVS operations;

d. Importance of cross-checking the HUD instrumentation presentations against the 

EFVS sensor image:

- Recognition of malfunctions of the navigation equipment;

- Recognition of improper presentation of elements in the visual scene during 

the approach;

e. EFVS system limitations, including specific differences between the pilot flying’s

(PF’s) EFVS display and the pilot monitoring’s (PM’s) display, if a PM display is 

installed;

f. Proper use of aircraft flight directors and autopilots:

- Autopilot minimum use height considerations;

- Altitude alerting systems during EFVS operations;

g. Use of barometric and/or radio altitude at low heights, including temperature 

correction if applicable;

h. Use of the FPV cue and FPARC; and

i. Use and limitations of supplementary or advisory vertical information for 

situation awareness below DA/DH or MDA.

3. EFVS sensor performance, sensor limitations, scene interpretation, visual anomalies, 

and other visual effects:

a. The specific sensor technology, sensor performance in varying weather 

conditions, the sensor’s ability to detect or not detect obstacles in the 
07/26/13 AC 90-106A

41

environment, and limitations where sensor performance can be variable and 

unpredictable;

b. Effect of crosswinds on EFVS field of view, including the use of caged and 

uncaged modes (if applicable) in crosswind conditions;

c. Visual anomalies such as “noise,” “blooming,” parallax, thermal crossover, and 

other visual effects; and

d. EFVS sensor limitations associated with specific types of lighting such as 

incandescent lamps and LEDs.

4. Preflight planning and operational considerations associated with using EFVS during 

taxi, takeoff, climb, cruise, descent, and landing phases of flight, including the use of 

EFVS for instrument approaches, operating below DA/DH or MDA, executing

missed approaches, landing, rollout, and balked landings:

a. IAP considerations:

- Use of EFVS on precision approaches, approaches with approved vertical 

guidance, and nonprecision approaches;

- Effects of various approach types on aircraft alignment with the runway at 

DA/DH or MDA during EFVS operations;

- Understanding of published VDAs, published VDPs, operator-calculated 

points for descent below MDA, VGSI angles, and the significance of VDA 

and VGSI angles that are not coincident; and

- Obstacle clearance awareness, including the potential for close-in obstacles on 

nonprecision approaches with no published VDP.

b. Transition from EFVS imagery to natural vision for detecting required visual 

references;

c. Normal and rejected landings, including loss of visual cues from the runway, 

TDZ, and rollout area;

d. Detecting runway incursions;

e. Missed approach considerations below DA/DH or MDA and after passing the 

MAP, including obstacle clearance awareness;

f. Crew briefings, procedures, callouts, and coordination items for EFVS operations, 

including annunciation of published minima and operation below the DA/DH or 

MDA:

- Duties of the PF and the PM during EFVS operations, as applicable;

- Flight planning, dispatch, or flight release considerations applicable to the 

operator’s EFVS authorization when flying into very low or below minimum 

conditions;

- Flight considerations for continuing past the FAF when below minimum 

conditions are reported.

5. Interpretation of approach and runway lighting systems and their display 

characteristics when using an EFVS:

a. Approach lighting systems;

b. Runway lighting systems;

c. Taxiway lighting systems; and
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42

d. LVO/SMGCS-specific lighting systems.
07/26/13 AC 90-106A

43

5.3. Initial Flight Training.

5.3.1. 14 CFR §§ 61.31(l)(3) and (4) contain the flight training requirements for EFVS I and 

EFVS II operations. Under § 61.31(l)(3), any person manipulating the controls of an 

aircraft or acting as PIC of an aircraft during an EFVS operation must receive flight 

training from an authorized instructor under a training program approved by the 

Administrator. In addition, the pilot must obtain a logbook or other endorsement from the

authorized instructor who certifies that he or she satisfactorily completed the flight 

training and is proficient in the use of EFVS. To provide the endorsement, the authorized 

instructor must also meet the requirements of § 61.31(l). These flight training

requirements apply to both EFVS I and EFVS II operations. Section 61.31(l)(7) contains 

certain exceptions to the § 61.31(l)(3) flight training required to conduct EFVS 

operations. Section 5.4 explains these exceptions. The definition of an “authorized 

instructor” can be found in § 61.1(b)(2), and section 5.7 of this AC explains what a 

“training program approved by the Administrator” means.

5.3.2. Under § 61.31(l), a person who serves as a required pilot flight crewmember during an 

EFVS I or EFVS II operation, but who does not manipulate the controls or serve as PIC 

of that aircraft, is not required to receive EFVS flight training. As discussed in Section

5.2.4, pilots should be aware that § 61.55 requires any person serving as second-incommand to be familiar with the operational procedures applicable to an aircraft’s 

powerplant; equipment and systems; performance specifications and limitations; its 

normal, abnormal, and emergency procedures; and flight manual, placards and markings. 

Part 61 contains the minimum training requirements for EFVS operations. In addition to 

the Part 61 requirements, pilots must also comply with the training provisions of the part 

under which they conduct flight operations. Part 121, for example, requires ground and 

flight training appropriate to the particular assignment of the pilot flight crewmember.

Error! Reference source not found.

5.3.3. Flight training must, at a minimum, consist of the following subjects in accordance with 

§ 61.31(l)(4):

1. Preflight and inflight preparation of EFVS equipment for EFVS operations, including 

EFVS setup and use of display, controls, modes, and associated systems, including 

adjustments for brightness and contrast under day and night conditions;

2. Proper piloting techniques associated with using EFVS during taxi, takeoff, climb, 

cruise, descent, landing, and rollout, to include missed approaches and balked 

landings;

3. Proper piloting techniques for the use of EFVS during instrument approaches, to 

include operations below DA/DH or MDA in accordance with § 91.176, as 

applicable, under both day and night conditions;

4. Determining enhanced flight visibility;

5. Identifying required visual references appropriate to EFVS operations;
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44

6. Transitioning from EFVS sensor imagery to natural vision acquisition of required 

visual references and the runway environment;

7. Using EFVS sensor imagery to touchdown and rollout, if EFVS operations as 

specified in § 91.176(a) are to be conducted; and

8. Normal, abnormal, emergency, and crew coordination procedures when using an 

EFVS, including crew procedures for using the pilot monitoring (PM) display.

5.3.4. For certain flight training requirements listed in Section 5.3.3, the FAA recommends that 

flight training address the following additional subject areas:

1. Preflight and inflight preparation of EFVS equipment for EFVS operations, including 

EFVS setup and use of display, controls, modes, and associated systems, including 

adjustments for brightness and contrast under day and night conditions:

a. Importance of the “design eye position” in acquiring the proper EFVS image;

b. Crew briefings, procedures, callouts, and coordination items for preflight and 

inflight preparation of EFVS equipment.

2. Proper piloting techniques associated with using EFVS during taxi, takeoff, climb, 

cruise, descent, landing, and rollout, to include missed approaches and balked 

landings:

a. Crew briefings, procedures, callouts, and coordination items for EFVS operations, 

including annunciation of published minima and operation below the DA/DH or 

MDA;

b. Missed approach procedures – all engines and engine inoperative; and

c. Use of on/off switch “clear” mode.

3. Proper piloting techniques for the use of EFVS during instrument approaches, to 

include operations below DA/DH or MDA in accordance with § 91.176, as 

applicable, under both day and night conditions:

a. Training items should be consistent with the operator’s authorization to conduct

EFVS operations. For example, training to conduct EFVS operations on

nonprecision approaches is not required if the operator does not conduct them and 

their authorization does not permit them. Other conditions and/or limitations may 

affect an operator’s training curriculum content;

b. Straight-in precision approaches, approaches with approved vertical guidance, and 

nonprecision instrument approaches: 

- In day and night Visual Flight Rules (VFR) and IFR conditions;

- Under various ceiling and low-visibility conditions;

- Using the FPV cue and FPARC during IFR approaches;

- Using different approach lighting configurations;

- Under various crosswind conditions;
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45

- To the extent practicable, approach to airports where there is a lack of on/off 

airport visual cues, no runway centerline lights, and no TDZ lights using the 

FPV cue and FPARC to simulate a “black hole” approach;

- IAPs flown to flare, touchdown, and rollout consistent with the operator’s 

authorization to conduct EFVS I or EFVS II operations;

- Maximum offset angles associated with the various types of straight-in 

instrument approach procedures the FAA has authorized an operator to 

conduct, consistent with the operator’s authorization or the equipment 

limitations of the AFM(S);

- Use of caged and uncaged modes in crosswind conditions; and

- Use of the EFVS repeater display (if installed).

4. Determining enhanced flight visibility:

a. Determining enhanced flight visibility over a range of actual or simulated lowvisibility conditions.
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46

5. In addition to normal, abnormal, emergency, and crew coordination procedures when 

using an EFVS, fight training should include crew procedures for using the pilot 

monitoring (PM) display if such a display is installed in the operator’s aircraft.

5.3.5. The FAA recognizes that an operator may choose to limit their EFVS operations in 

specific ways. For example, an operator may choose to conduct EFVS I operations only

on precision approaches and approaches with published vertical guidance, but not on 

nonprecision approaches. Another operator may choose to tailor its EFVS operation in 

other specific ways. In the example given, training to conduct EFVS I operations on 

nonprecision approaches would not be required. The FAA can tailor an operator’s 

authorization and training to the type of EFVS operation to be conducted and any

applicable operating limitations would be specified in the operator’s OpSpec, MSpec, or 

LOA. In the example given, the operator’s OpSpec, MSpec, or LOA would authorize 

them to conduct EFVS I operations only on precision approaches and approaches with 

published vertical guidance. The FAA would not authorize nonprecision approaches for 

that operator’s EFVS I operations.

5.3.6. The FAA assumes that an operator who conducts EFVS II operations will also train their

pilots to conduct EFVS I operations; specifically, the operator must train on the transition 

from enhanced vision to natural vision at 100 feet above the TDZE. Under certain 

circumstances, an operator authorized to conduct EFVS II operations might find it 

necessary to conduct an EFVS I operation. One example could be when equipment, such 

as the PM display, is inoperative. A PM display is required for an EFVS II operation 

when a minimum of more than one pilot flightcrew member is required. It is not required 

for an EFVS I operation, however. In this example, the flightcrew cannot conduct an 

EFVS II operation because the PM display is inoperative, but they can conduct an EFVS 

I operation provided they meet all of the other regulatory requirements for EFVS 

operations.

5.3.7. The FAA considers it essential that pilots be trained and checked on the various types of 

IAPs the FAA authorizes them to conduct. If an operator conducts EFVS I operations on 

straight-in nonprecision approaches, they should conduct EFVS training on a range of 

offset angles over a range of standard and lower-than-standard visibilities. A non-RNAV 

nonprecision approach, for example, can be offset by as much as 30 degrees and be 

considered straight-in. If an operator conducts EFVS I or EFVS II operations on straightin precision approaches and approaches with approved vertical guidance (i.e., published 

vertical guidance), they should conduct training on the range of offset angles associated 

with those IAPs and at various standard and lower-than-standard visibilities. Section 

3.3.3., Offset Approaches, addresses offset angles associated with specific IAPs.

5.4. Exceptions to the Initial Ground and Flight Training Requirements of 14 CFR 

61.31(l)(1) and (l)(3).

5.4.1. The ground training requirements of § 61.31(l)(1) and the flight training requirements of 

§ 61.31 (l)(3) do not apply if a person has satisfactorily completed the following:
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47

 A pilot proficiency check on EFVS I or EFVS II operations as specified in 

§ 91.176(a) or (b); or

 A training program, proficiency check, or other course of instruction applicable to 

EFVS I operations conducted under § 91.176(b) that is found to be acceptable to the

Administrator and was completed before [INSERT DATE TWO YEARS AFTER 

THE EFFECTIVE DATE OF THE FINAL RULE]. 

5.4.2. A pilot who is excepted from the initial ground and flight training requirements of 

§§ 61.31(l)(1) and (l)(3), based on having satisfactorily completed a pilot proficiency

check on EFVS I or EFVS II operations as specified in § 91.176(a) or (b), must have a 

logbook endorsement stating that the pilot has satisfactorily completed the check. In 

addition, the proficiency check must be applicable to the specific type of EFVS operation

the pilot will conduct – EFVS I and/or EFVS II. For example, a proficiency check 

conducted for EFVS I operations would not meet the requirement for a proficiency check 

for EFVS II operations. An EFVS I operation requires a transition from sensor imagery to 

natural vision at 100 feet above the touchdown zone elevation, whereas, an EFVS II 

operation relies on the sensor image to touchdown. Additionally, a proficiency check for 

EFVS II operations may not meet all of the requirements for a proficiency check for 

EFVS I operations because it may not include nonprecision approaches. A proficiency

check for EFVS II operations could be combined with a proficiency check for EFVS I

operations that addresses the conduct of nonprecision approaches, however. The purpose 

of this exception is to give credit for EFVS ground and flight training a pilot may have 

received other than through a Part 141 pilot school or a Part 142 training center or to 

provide a means of demonstrating EFVS proficiency that may have been obtained by

other means. Under this provision, the pilot proficiency check must be conducted by:

 An FAA inspector or designated examiner;

 A person authorized by the U.S. Armed Forces to administer EFVS proficiency

checks, provided the person receiving the check was a member of the U.S. Armed 

Forces at the time the check was administered; 

 An authorized instructor employed by a Federal, State, county, or municipal agency 

to administer an EFVS proficiency check, provided the person receiving the check 

was employed by that agency at the time the check was administered; or

 A check airman under Part 121, 125, or 135, or a program manager check pilot under 

check pilot under Part 91, subpart K.

5.4.3. The ground and flight training requirements of §§ 61.31(l)(1) and (l)(3) also do not apply

if a person has satisfactorily completed a training program, proficiency check, or other 

course of instruction applicable to EFVS I operations conducted under § 91.176(b) that is 

acceptable to the Administrator before [INSERT DATE 24 MONTHS AFTER THE 

EFFECTIVE DATE OF THE FINAL RULE]. The purpose of this exception is to provide 

pilots who were conducting EFVS I operations prior to the establishment of EFVS 

training requirements in § 61.31 a reasonable means of demonstrating compliance with 

the additional ground and flight training requirements of §§ 61.31(l)(1) and (l)(3). The 

training program, proficiency check, or other course of instruction could have been 

completed prior to the establishment of EFVS training requirements in § 61.31, but not 
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48

later than [INSERT DATE 24 MONTHS AFTER THE EFFECTIVE DATE OF THE 

FINAL RULE]. To qualify for this exception, a pilot must be able to show a logbook 

endorsement or other training record that indicates he or she satisfactorily completed a

training program, proficiency check, or other course of instruction applicable to EFVS I 

operations that the FAA finds acceptable. Training the FAA finds acceptable under this 

provision could be training conducted under Part 61, Part 141, Part 142, training 

conducted by an air carrier, the military, a Federal, State, county, or municipal agency, a 

corporate flight department, or another course of instruction the FAA might find 

acceptable. The training need not be a training program that is approved by the FAA, but 

to be acceptable, the course of instruction should cover the subjects required by

§ 61.31(l). If a proficiency check is used to establish the basis for this exception, the 

proficiency check must be performed by:

 An FAA Inspector or designated examiner who is qualified to perform EFVS 

operations in that same aircraft category;

 A person who is authorized by the U.S. Armed Forces to perform EFVS proficiency

checks, provided the person being administered the check is also a member of the 

U.S. Armed Forces;

 A company check pilot who is authorized to perform EFVS proficiency checks under 

part 121, 125, 135, or subpart K of part 91 of 14 CFR, provided that both the check 

pilot and the pilot being tested are employees of that operator or fractional ownership 

program manager, as applicable;

 An authorized instructor who meets the additional training requirements for EFVS 

operations specified in § 61.31(l); or

 A person approved by the FAA to perform EFVS proficiency checks.

5.5. Recurrent or Differences Training.

5.5.1. Recurrent and differences training for EFVS I and EFVS II operations should consist of 

the same subject areas covered by initial training. Differences training for a new EFVS 

system should also include special conditions or considerations associated with 

conducting EFVS operations using the new system.

5.5.2. An operator may conduct less than the full range of EFVS operations permitted by the 

regulations as a result of equipment limitations, operator choice, or other operating

considerations and limitations. For example, an operator’s aircraft may currently be 

certified to only conduct EFVS I operations, and its pilots are only trained to conduct 

those operations. That operator may later decide to certify its aircraft for EFVS II 

operations. Because the operator’s pilots would have already completed initial EFVS I 

ground and flight training, the FAA would only require them to complete differences

training applicable to EFVS II operations. In this case, the operator would be required to 

complete ground and flight training that addresses the differences between the two types 

of EFVS operations and amend their OpSpec, MSpec, or LOA authorization, as 

applicable. Another example of when differences training is appropriate would be when 

an operator who is authorized to conduct EFVS I operations only on precision approaches 

applies for approval to also conduct them on approaches with approved vertical guidance 

and on nonprecision approaches. As discussed in Sections 5.3.5 through 5.3.7, ground 
07/26/13 AC 90-106A

49

and flight training that addresses the additional considerations applicable to the additional 

approach procedures is required. Yet another example is an operator who conducts

operations under Part 135 whose OpSpec to conduct EFVS operations does not currently 

authorize them to take off under IFR or begin an IAP when the weather at the destination 

airport is reported to be below the authorized landing minimums for that airport. To

takeoff under IFR or to begin the IAP, the operator in this example would have to amend 

their OpSpec authorization and complete differences training applicable to the new 

operations the operator will conduct. 

5.5.3. Successful completion of recurrent and differences training must be documented by a

logbook or other endorsement from an authorized instructor. In lieu of completing 

recurrent or differences training, a pilot could complete a proficiency check on the 

additional EFVS operations administered by an FAA inspector, designated examiner, a 

check airman under Part 121, 125, or 135, or a program manager check pilot under Part 

91, subpart K. 

5.6. Aircraft or Flight Simulator Training.

5.6.1. Flight training for EFVS must be accomplished in the actual aircraft or in a simulator that 

meets the requirements of § 61.31(l)(5). A flight simulator used to meet the flight training 

requirements specified in § 61.31(l)(3) must be equipped with an EFVS and must be a 

level 'C' simulator with a daylight visual display, or a level 'D' simulator. The National 

Simulator Program must qualify each simulator for EFVS. You can find additional 

information about the FAA National Simulator Program (NSP) at 

http://www.faa.gov/safety/programs_initiatives/aircraft_aviation/nsp/. 

5.6.2. In FSB Reports, the FAA recommends that each pilot who manipulates the controls 

during an EFVS operation should receive at least a minimum of 4 hours of initial ground 

training followed by a minimum of 2 hours of flight training using an EFVS in an EFVSequipped aircraft or in an EFVS-equipped and qualified flight simulator. This assumes 

the pilot is already trained and proficient in the use of the HUD installed on the aircraft. If 

the pilot is not trained and proficient in the use of the HUD, the pilot may require more 

training time. The pilot may accomplish HUD training concurrently with EFVS training.

Additional training time may also be required depending on the EFVS operations the 

operator expects to conduct. 

5.6.3. The simulator’s out-the-window visibility and EFVS enhanced flight visibility should be 

adjustable and should be set to realistic values during training.

5.7. Approved EFVS Training Program.

5.7.1. The regulations require a pilot to receive training from an authorized instructor under a

training program approved by the Administrator. A training program approved by the

Administrator could include EFVS training received through a training program approved 

under Part 121, 125 or 135, a Part 141 pilot school, a Part 142 training center, or FAAapproved training given under Part 61. The FAA approves EFVS training conducted 

under Part 121, 125, 135, 141, or 142 using existing processes. An operator or training 
07/26/13 AC 90-106A

50

provider who wishes to obtain approval to provide EFVS training under Part 61 should 

submit the ground and/or flight training curriculum for EFVS to the Flight Standards 

District Office with geographic responsibility for the operator or for the training provider, 

as appropriate. At a minimum, the training program must contain the subject areas 

specified in § 61.31(l).
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51

6. Recent Flight Experience and Proficiency Requirements for EFVS Operations

6.1. Recent Flight Experience Requirements for EFVS Operations.

6.1.1. EFVS operations are complex operations involving the use of a HUD with a sensor image 

that a pilot typically conducts in low-visibility conditions. Because the occurrence of 

low-visibility conditions is infrequent, and because the skills necessary to operate EFVS 

equipment under these conditions are perishable, recent EFVS flight experience is 

necessary to prevent the loss of skill. The purpose of requiring recent EFVS flight 

experience is to ensure that a pilot remains proficient in the use of all EFVS components 

and operating procedures and to ensure that the pilot conducts EFVS operations safely. 

As EFVS equipment evolves to permit operations in lower visibility environments than 

are currently permitted, and as the scope and number of EFVS operations increases over 

time, the need for pilots to maintain recent flight experience becomes even more critical.

6.1.2. 14 CFR § 61.57(h) specifies that a person who manipulates the controls of an aircraft 

during an EFVS operation or who acts as PIC of an aircraft during an EFVS operation, 

can do so only if, within 6 calendar months preceding the month of the flight, that person 

performs and logs six instrument approaches as the sole manipulator of the controls using 

an EFVS. The recent flight experience requirements specified in § 61.57(h) apply to both 

EFVS I and EFVS II operations. Unlike the instrument experience requirements specified 

in § 61.57(c), these approaches need not be conducted in actual weather conditions or 

under simulated conditions using a view-limiting device. Since the EFVS can present a 

sensor image to the pilot in both IFR and VFR weather conditions, the pilot may conduct

these approaches under any weather conditions. One approach must terminate in a full 

stop landing. Pilots who conduct EFVS II operations must conduct the full stop landing 

using the EFVS.

6.1.3. In accordance with the provisions of § 61.57(e)(2), the recent flight experience 

requirements specified in § 61.57(h) do not apply to a PIC who is employed by an air 

carrier certificated to conduct operations under Part 121 or 135. The pilot, however, must 

be engaged in a flight operation under Part 91, 121, or 135 for that air carrier and in 

compliance with §§121.437 and 121.439, or §§135.243 and 135.247, as appropriate. 

Additionally, § 91.176 requires each pilot flight crewmember to meet the applicable 

training, testing, and qualification provisions of Part 121 or 135, as appropriate.

6.1.4. The recent flight experience requirements of § 61.57(h) can be met in an aircraft or in a 

simulator equipped with an EFVS. If an EFVS-equipped simulator is used, it must be a 

level “C” simulator, with a daylight visual display, or a level “D” simulator that the FAA 

National Simulator Program (NSP) has qualified for EFVS. 

6.2. Proficiency Check Requirements for EFVS Operations.

6.2.1. Under § 61.57(i), a person acting as PIC or a person who is manipulating the controls of 

an aircraft in an EFVS operation must either meet the recent flight experience 

requirements of § 61.57(h) or pass an EFVS proficiency check. The proficiency check 

must consist of the training tasks specified in § 61.31(l) and must be performed in the 
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52

category of aircraft for which the person is seeking the EFVS privilege or in a flight 

simulator that is representative of that category of aircraft. If the pilot uses a flight 

simulator to accomplish the proficiency check, it must be equipped with an EFVS and 

must be a level “C” simulator, with a daylight visual display, or a level “D” simulator that 

the FAA NSP has qualified for EFVS.

6.2.2. An EFVS proficiency check must be performed by:

 An FAA Inspector or designated examiner who is qualified to perform EFVS 

operations in that same aircraft category;

 A person who is authorized by the U.S. Armed Forces to perform EFVS proficiency

checks, provided the person being administered the check is also a member of the 

U.S. Armed Forces;

 A company check pilot who is authorized to perform EFVS proficiency checks under 

Part 121, 125, or 135 or subpart K of Part 91 of 14 CFR, and provided that both the 

check pilot and the pilot being tested are employees of that operator or fractional 

ownership program manager, as applicable;

 An authorized instructor who meets the additional training requirements for EFVS 

operations specified in § 61.31(l) and when conducting a proficiency check in an 

aircraft the recent flight experience specified in § 61.57(h) or (i); or

 A person the FAA has approved to perform EFVS proficiency checks.
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53

7. Training for Dispatchers and Other Persons Authorized to Exercise Operational 

Control for EFVS Operations

7.1. Dispatch, Flight Release and Flight Following Considerations.

7.1.1. The regulatory requirements pertaining to dispatch, flight release, and takeoff under IFR 

for operators conducting EFVS operations under Part 121, 125, or 135 when the 

destination airport visibility is below authorized minimums are discussed in detail in 

Section 4.1. Section 4.2 addresses the regulatory requirements pertaining to initiating or 

continuing an approach using EFVS when the reported visibility is below the minimum 

authorized visibility for the approach to be flown for operations conducted under Part 

121, 125, or 135. This section addresses training for dispatchers and other persons 

authorized to exercise operational control for EFVS operations.

7.1.2. With careful flight planning, detailed weather analysis, and proper training, EFVS 

equipment can greatly enhance operational safety and access to airports. To ensure that 

an approach and landing can be successfully completed using EFVS, it is essential that 

dispatchers and other persons authorized to exercise operational control fully understand 

the capabilities and limitations of the specific EFVS equipment installed in the operator’s 

aircraft. Unique weather conditions that cause variability in how an EFVS sensor 

performs, or weather conditions that exceed the sensor’s ability to provide the enhanced 

flight visibility required to complete the approach and landing, should be understood and 

accounted for when dispatching an aircraft, releasing an aircraft, or taking off under IFR 

for the purpose of conducting EFVS operations. Operators who do not have dispatch or 

flight release personnel, such as an operation conducted under Part 135, should be 

especially aware of weather and operational factors that could affect EFVS performance 

when they are considering takeoff under IFR, or when conditions at their destination 

airport are forecasted or reported to be below visibility minimums for the approach to be 

flown. Operational planning and continuous monitoring of weather conditions at the 

destination airport are especially important under these circumstances.

7.1.3. It is also important to understand that air traffic flow at many airports is constrained by 

weather conditions other than wind. Dispatching or releasing an aircraft to an airport 

where the pilot must conduct an EFVS operation due to low visibility should consider air 

traffic flow to that airport. During some CAT II or III approach conditions, a pilot who 

wishes to conduct an approach using EFVS to a different runway than is being used for 

CAT II or III operations may not be cleared by air traffic control to conduct an approach

to that runway due to traffic flow or other conditions, irrespective of the provisions of the 

EFVS regulations or the aircraft’s capability to conduct EFVS operations. As a result, 

increased fuel for holding could be required due to limited runway capacity.

7.1.4. Airports certificated under Part 139 will have restrictions affecting surface movement 

operations when RVR values are reported to be approaching or are less than RVR 1200 

feet. Each airport approved for operations below RVR 1200 feet develops LVO/SMGCS 

taxi routes, surface movement restrictions, and air traffic coordination procedures. The 

FAA-approved LVO/SMGCS plan can limit availability of runways for takeoff and 

landing. Taxiways not included in the LVO/SMGCS plan may not be available to an 
07/26/13 AC 90-106A

54

operator, even though EFVS may provide significant visual benefits during ground 

movement. Operators, dispatchers, and other persons authorized to exercise operational 

control should check with the airport operator for specific airport procedures. FAA Order 

8000.94, Procedures for Establishing Airport Low-Visibility Operations and Approval of 

Low-Visibility Operations/Surface Movement Guidance and Control System Operations,

and AC 120-57, Surface Movement Guidance and Control System, provides standards 

and guidance for LVO/SMGCS operations. 

7.2. Initial Training for Dispatchers and Other Persons Authorized to Exercise 

Operational Control.

7.2.1. Initial training for dispatchers and other persons authorized to exercise operational 

control should consist of the following:

1. Regulatory requirements applicable to the EFVS operation(s) the operator will 

conduct (e.g., EFVS I or EFVS II):

a. Operational concept for EFVS I and EFVS II operations;

b. Regulatory requirements for EFVS operations contained in §§ 91.175(d)(1), 

91.175(e)(1), 91.176, and 91.189(d) and (e);

c. Regulatory requirements for pilot training, recent flight experience, and 

proficiency contained in §§ 61.31(l) and 61.57(h) and (i);

d. Regulatory requirements contained in §§ 121.613, 121.615(a), 125.361, 

125.363(a), and 135.219, as applicable, for dispatch, flight release, or takeoff 

under IFR using an EFVS-equipped aircraft when the reported or forecast 

visibility at the destination airport is below authorized minimums ;

e. Regulatory requirements contained in §§ 121.651, 125.325, 125.381, and 

135.225, as applicable, for initiating or continuing an approach when the 

destination airport visibility is below authorized minimums;

f. IAPs approved and not approved for EFVS I and EFVS II operations;

g. Enhanced flight visibility requirements contained in §§ 91.176(a) and (b);

h. Visual reference requirements contained in §§ 91.176(a) and (b), including a

comparison of visual references required by § 91.175(c) using natural vision and 

§§ 91.176(a) and (b) using EFVS;

i. OpSpec or LOA requirements pertinent to the EFVS operation the pilot will 

conduct; and

j. Exemptions or deviations from the regulations that pertain to the use of EFVS, if 

any.

2. AFM/AFMS material pertinent to EFVS operations:

a. Type of EFVS operation the FAA has certified the operator’s aircraft to conduct;

b. EFVS system description and operating limitations; and

c. Normal, abnormal, and emergency procedures pertaining to the operator’s EFVS, 

including an understanding of pilot flying and pilot monitoring duties, and 

decision points throughout the EFVS operation.
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55

3. Sensor technology, performance, and limitations:

a. Understanding the specific EFVS sensor technology or technologies installed on 

the operator’s aircraft;

b. EFVS sensor performance in varying weather conditions;

c. EFVS sensor limitations, including variable, unpredictable, or unusual 

performance characteristics;

d. Weather conditions that exceed the EFVS sensor’s ability to provide the enhanced 

flight visibility required to complete the approach and landing;

e. The EFVS sensor’s ability to detect or not detect obstacles in the environment; 

and

f. EFVS sensor performance and limitations associated with specific types of 

lighting such as incandescent lamps and LEDs.

4. EFVS dispatch or flight release requirements for destination airports and for initiating 

and continuing an approach using EFVS when the destination airport visibility is 

below authorized minimums;

5. Considerations for diverting to alternate airports;

6. Procedures for redispatch en route with respect to EFVS operations;

7. MEL/CDL dispatch/flight release requirements and considerations;

8. Use of barometric and/or radio altitude at low heights, including temperature 

correction if applicable;

9. Use and limitations of supplementary or advisory vertical information for situation 

awareness below DA/DH or MDA;

10. Effect of crosswinds on EFVS field of view for approaches aligned with the runway

centerline and for straight-in approaches that are offset from the runway centerline;

11. Runway, taxiway, and approach lighting system configurations; and

12. Capabilities and limitations of EFVS for low-visibility taxi, including operating 

considerations when LVO/SMGCS plans are in effect.

7.2.2. During initial training, the FAA encourages dispatchers or other persons authorized to 

exercise operational control to experience a training event in a flight simulator or an

actual airplane that allows them to observe a flight crew conducting an EFVS I or EFVS 

II operation. If a flight simulator is used, it should be equipped with an EFVS, and should

be a level 'C' simulator with a daylight visual display, or a level 'D' simulator that has 

been qualified by the NSP for EFVS. The purpose of this training event is to provide an 

opportunity for dispatchers and other persons authorized to exercise operational control 

to understand what an EFVS operation is, what the enhanced flight visibility and visual 

reference requirements for the operation are, the challenges that variable sensor 

performance present to the flight crew, and how critical the dispatch, flight release, or
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56

flight following functions are. If a training event in a flight simulator or airplane is not 

possible, training material that addresses these elements during the conduct of an EFVS I 

or EFVS II operation may be developed and shown to the person being trained. For 

persons conducting operations under Part 121, the simulator training event could fulfill 

the annual operating familiarization required by § 121.463. 

7.3. Recurrent and Differences Training for Dispatch and Flight Release Personnel.

7.3.1. Recurrent and differences training for dispatchers and other persons authorized to 

exercise operational control should consist of the same subject areas covered by initial 

training. Differences training for a new EFVS system should also include special 

conditions or considerations associated with conducting EFVS operations using the new 

system.
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57

8. Aircraft Qualification and Maintenance Program Requirements

8.1. General.

8.1.1. This section contains guidance on aircraft qualification and maintenance program 

requirements associated with EFVS I and EFVS II operations. Operators should address 

these requirements in applications submitted to the FAA for authorization to conduct 

EFVS operations. Section 10 contains additional information about the application 

process.

8.2. Applicability.

8.2.1. Aircraft qualification and maintenance requirements apply to EFVS I and EFVS II 

operations that are conducted under Parts 91, 91 subpart K, 121, 125, 129, and 135. All 

operators must submit an application for approval to conduct EFVS I operations, except 

for Part 91 operators (other than Part 91, subpart K operators) who wish to conduct only

EFVS I operations. Operators other than a Part 91 operator who wish to conduct only

EFVS I operations must submit an application that addresses the qualification and 

maintenance requirements, as applicable, that are specified in this section. All operators, 

including Part 91 operators, who wish to conduct EFVS II operations must submit an 

application that addresses the qualification and maintenance requirements as applicable, 

that are specified in this section.

8.2.2. Part 91 operators who wish to conduct only EFVS I operations should be aware that their 

aircraft must still be qualified to conduct EFVS I operations. That is, their U.S.-registered 

aircraft must comply with the equipment requirements of 91.176(b)(1) and must have a 

TC, STC, or ATC to conduct EFVS I operations. Accordingly, a Part 91 operator of a 

U.S.-registered aircraft must maintain the aircraft in accordance with the maintenance, 

preventive maintenance, and alterations requirements specified in Parts 91 and 43.

8.3. Aircraft Qualification Requirements.

8.3.1. An EFVS installed on a U.S.-registered aircraft that is used to conduct EFVS I and EFVS 

II operations must be operable and must be installed in accordance with an FAA type 

design approval (a TC, ATC, or STC). A field approval is not an acceptable means of 

EFVS installation for operations conducted under § 91.176(a) or (b). A foreign-registered 

aircraft used to conduct EFVS operations that does not have an FAA type design 

approval must be equipped with an operable EFVS that otherwise meets the requirements 

of the U.S. regulations.

8.3.2. Applications for authorization to conduct EFVS I or EFVS II operations should contain 

the following documentation and information to establish that the aircraft qualifies for 

EFVS operations:

1. Applicable EFVS airworthiness documentation that indicates the EFVS was installed 

pursuant to an FAA type design approval or for foreign-registered aircraft, that the 

EFVS otherwise meets the requirements of the U.S. regulations
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58

2. EFVS manufacturer’s Instructions for Continued Airworthiness (ICA) as accepted by 

the FAA, and

3. Proposed Minimum Equipment List (MEL) revisions, if applicable, listing any

limitations associated with EFVS I or EFVS II operations.

8.4. Maintenance Program.

8.4.1. Applications for authorization to conduct EFVS I or EFVS II operations should include

the operator’s maintenance program and should address specific policy and procedures 

that apply to continuing airworthiness of the EFVS. 

8.4.2. Except for operators conducting EFVS I operations under Part 91, applications for 

authorization to conduct EFVS operations under Parts 91 subpart K, 121, 125, 129, and 

135 should include the following:

1. The General Maintenance Manual (GMM) must incorporate the EFVS 

manufacturer’s ICA, as accepted by the FAA, and identify any special techniques, 

maintenance/inspection frequencies, and test equipment required to support the 

continued airworthiness of the system;

2. Indicate whether the EFVS maintenance program is integrated into an existing 

approved maintenance program (e.g., lower landing minima program) or a separate 

program;

3. Identify the GMM revision and update procedures, if not previously approved by the 

FAA;

4. Identify how maintenance personnel will be trained and qualified on the EFVS and 

the method to record and maintain their qualifications;

5. Procedures for EFVS software installation, updating, evaluation, testing and control;

6. Procedures used to make modifications, additions, and changes to the EFVS;

7. Procedures for EFVS discrepancy reporting and recording;

8. Procedures for MEL and logbook pertaining to upgrade/downgrade/deferral of the 

EFVS;

9. Procedures for MEL (remarks section, limitations, upgrade/downgrade) that ensure 

the EFVS status is placarded properly and clearly documented in the aircraft log 

book;

10. Procedures for notification between maintenance control, engineering, flight 

operations, and dispatch, or equivalent, when an aircraft’s EFVS status changes;
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59

11. Procedures to ensure the downgrade of an aircraft’s EFVS status, if applicable, when 

maintenance was performed on the EFVS by nonqualified persons;

12. Procedures to monitor and identify aircraft with chronic EFVS discrepancies and 

restrict the aircraft from EFVS operations until appropriate corrective action and tests 

have been performed;

13. Procedures for return to service (RTS) of an EFVS following routine/nonroutine 

maintenance or completion of corrective action on an aircraft flagged for chronic 

discrepancies, including:

a. Required tests for RTS

b. Functional flight test requirements

c. Component mount or rack removal/installation

d. Structural damage or modification affecting EFVS optical alignment or system 

performance, and

e. Interchange of EFVS I or EFVS II component allowances/restrictions.

14. Integration of EFVS program into Quality Control and Analysis (QA) Program;

15. Procedures for periodic performance sampling;

16. Procedures to ensure appropriate EFVS I and EFVS II parts handling, if applicable:

a. Identification/segregation

b. Component tracking and control procedures, and

c. Component modification tracking procedures resulting from Airworthiness 

Directives, engineering orders, etc.).

17. Required Inspection Item (RII) components, systems, and software (if applicable).

8.4.3. Maintenance personnel should be familiar with the operator’s approved program, their 

individual responsibilities with respect to that program, and the availability of any 

resources within or outside of the maintenance organization necessary to ensure program 

effectiveness.
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60

9. Maintenance Training for EFVS Operations

9.1. General.

9.1.1. This section contains guidance on maintenance personnel training requirements 

associated with EFVS I and EFVS II operations. Operators should address these 

requirements in proposals submitted to the FAA for authorization to conduct EFVS 

operations. Section 10 contains additional information about the application process.

9.2. Maintenance Training

9.2.1. Maintenance personnel should be knowledgeable of the guidance contained in this AC

and applicable regulations. Operator and contract maintenance personnel, including 

mechanics, maintenance controllers, avionics technicians, and inspection/quality

assurance personnel should receive initial and recurrent training to establish and maintain

an effective EFVS maintenance program. 

9.2.1.1. Applications submitted for authorization to conduct EFVS I or EFVS II operations 

should address the following maintenance training items: 

1. Identify the person(s) responsible for ensuring EFVS maintenance and inspection 

personnel are properly trained, knowledgeable, and current in accordance with the 

GMM

2. Identify how the EFVS training will be conducted (i.e., in-house or outside training 

provider)

3. Include policy and procedures that address the qualification requirements of EFVS 

maintenance and inspection personnel

4. Identify the methods and techniques used to conduct initial and recurrent training 

(e.g., instructor led, computer-based, OJT, etc) 

5. Identify the procedures used to record and maintain the training required for initial 

and recurrent EFVS qualifications

6. Include the EFVS maintenance and inspection training curriculum that addresses the 

following topics:

a. Operational overview

b. EFVS system overview

c. EFVS maintenance and inspection procedures

d. EFVS personnel training qualification requirements for EFVS I and EFVS II

e. EFVS I and EFVS II upgrade/downgrade procedures, including applicable 

status change notifications

f. MEL procedures 

g. Test equipment and use

h. Return to service tests and procedures, and 
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i. EFVS parts handling procedures, including handling of outside vendor parts.
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10. Operational Approval Process for EFVS Operations

10.1. Approval Process Overview.

10.1.1. The approval process is an orderly method used by FAA Flight Standards inspectors to 

ensure operators meet regulatory standards and provide for safe operating practices. The 

process consists of five distinct, yet related, phases and can result in approving or not 

approving an operator’s proposal. The process consists of the following five phases:

10.1.1.1. Phase One – Pre-Application. Phase One of the approval process begins when an 

operator requests authorization from the FAA to conduct EFVS operations. The FAA 

Certificate-Holding District Office (CHDO) or Flight Standards District Office 

(FSDO) responsible for that operator and the operator must reach a common 

understanding of what the operator must do, what role the FAA will have, and what 

form, content, and documents are required for submission.

10.1.1.2. Phase Two – Formal Application. Phase Two begins when the operator submits a 

proposal to the FAA for formal evaluation. During this phase, the FAA reviews the 

operator’s submission to ensure that the operator has clearly defined the proposal and 

provides the documentation specified in Phase One. The required information must be 

complete and detailed enough to permit a thorough evaluation of the operator’s 

capability and competence to satisfy fully the applicable regulations, national policy, 

and safe operating practices. The POI facilitates coordination with the appropriate 

Aircraft Evaluation Group (AEG) and Aircraft Certification Office (ACO), and the 

Regional Flight Standards Division (RFSD), as necessary.

10.1.1.3. Phase Three – Document Compliance. Phase Three begins when the FAA starts its 

indepth review and analysis of the operator’s proposal. In this phase, the FAA 

evaluates the proposal to determine that it is not contrary to applicable FAA 

regulations, FAA guidance, or other safety-related documents, and provides for safe 

operating practices. Planning for Phase Four also begins as the FAA starts to 

formulate plans to observe and evaluate the operator’s ability to perform.

10.1.1.4. Phase Four – Demonstration and Inspection. Phase Four is the major validation 

phase of the process referred to as the Operational Use Suitability Demonstration 

(OUSD). It is an operational evaluation of the operator’s ability to function in 

accordance with the proposal evaluated in Phase Three. The purpose of an OUSD is to 

demonstrate and validate the ability of the operator to:

 Maintain and operate its EFVS equipment;

 Achieve an acceptable level of EFVS equipment reliability; and

 Perform EFVS operations during line operations in a manner consistent with the 

concepts specified in this AC.

OUSD requirements may include criteria and special emphasis items from FSB reports 

applicable to the EFVS/aircraft installation, previous operator service experience, 

experience other operators may have with a specific EFVS/aircraft installation, 
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63

experience the operator’s crews have with EFVS, and other factors the FAA deems 

appropriate. In this phase, the FAA finalizes plans to observe and evaluate the 

operator’s demonstration of its ability to perform in accordance with the procedures, 

guidelines, and parameters described in the formal proposal. Phase Four concludes 

when the operator provides sufficient proof to satisfy the FAA’s requirements for 

meeting all the plan objectives or when the operator is unable to complete them 

satisfactorily. 

10.1.1.5. Phase Five – Approval. In Phase Five, the FAA approves the operator’s proposal. If 

the FAA does not approve the proposal, they notify the operator in Phase Three or 

Four. The operations inspector with oversight responsibility for the operator grants 

approval for the operational use of the EFVS through the issuance of OpSpecs, 

MSpecs, or an LOA.

10.2. Authorizations to Conduct EFVS Operations.

10.2.1. The FAA requires an authorization for persons conducting EFVS I operations under Parts

91, subpart K, 121, 125, 129, and 135 as follows:

 A person who conducts EFVS I operations under Part 91, subpart K must do so in 

accordance with MSpecs authorizing the use of EFVS;

 Persons who conduct EFVS I operations under Part 121, 129, or 135 must do so in 

accordance with OpSpecs authorizing the use of EFVS;

 A person who conducts EFVS I operations under Part 125 must do so in accordance 

with OpSpecs authorizing the use of EFVS, or in the case of a Part 125 LODA holder, 

an LOA for the use of EFVS; and

 Part 91 operators (other than Part 91, subpart K operators) are not required to obtain 

an LOA to conduct EFVS I operations.

10.2.2. The FAA requires an authorization for all persons conducting EFVS II operations under 

Parts 91, 121, 125, 129, and 135 as follows:

 A person who conducts EFVS II operations under Part 91 (other than Part 91, subpart 

K) must do so in accordance with an LOA for EFVS II operations;

 A person conducting EFVS II operations under Part 91, subpart K must conduct them 

in accordance with MSpecs authorizing the use of EFVS;

 Persons who conduct EFVS II operations under Part 121, 129, or 135 must do so in 

accordance with OpSpecs authorizing the use of EFVS; and

 A person who conducts EFVS II operations under Part 125 must do so in accordance 

with OpSpecs authorizing the use of EFVS, or in the case of a Part 125 LODA holder, 

an LOA for the use of EFVS.

10.2.3. The FAA authorizes EFVS operations through a specific OpSpec, MSpec, or LOA, 

depending on the level of EFVS operation the operator will conduct and whether the 

operator plans to dispatch, release a flight, or takeoff under IFR or to initiate and continue 

an approach when the destination airport weather is below authorized visibility
07/26/13 AC 90-106A

64

minimums for the runway of intended landing. Following are the specific OpSpec, 

MSpec, or LOA designations and authorizations:

 The FAA issues OpSpec C048, MSpec MC048, or LOA C048 to an operator who is 

conducting an EFVS I operation, but who is not requesting authorization to dispatch, 

release a flight, or takeoff under IFR or to initiate and continue an approach when the 

destination airport weather is below authorized visibility minimums for the runway of 

intended landing;

 The FAA issues OpSpec C348, MSpec MC348, or LOA C348 to an operator who is 

conducting an EFVS I operation and who is also requesting authorization to dispatch, 

release a flight, or takeoff under IFR or to initiate and continue an approach when the 

destination airport weather is below authorized visibility minimums for the runway of 

intended landing; and

 The FAA also issues OpSpec C348, MSpec MC348, or LOA C348 to an operator 

who is conducting EFVS II operations whether or not they are also requesting 

authorization to dispatch, release a flight, or takeoff under IFR or to initiate and 

continue an approach when the destination airport weather is below authorized 

visibility minimums for the runway of intended landing.
07/26/13 AC 90-106A

65

10.3. Approval Process for EFVS I Operations Conducted Under Part 91 subpart K, 121, 

125, or 135 and EFVS II Operations Conducted Under Part 91, 121, 125, or 135.

10.3.1. Application Process. After meeting with the CHDO or FSDO, as applicable, operators 

should submit a request for authorization to use an EFVS, along with supporting 

information and documentation, to the FAA POI identified during the initial Phase One 

meeting. The major components of an EFVS application should include the following 

required documents:

1. Application letter describing the level of EFVS operation to be conducted (i.e., EFVS 

I, EFVS II, or both), including whether the operator is requesting authorization to 

dispatch, release a flight, or takeoff under IFR or to initiate and continue an approach 

when the destination airport weather is below authorized visibility minimums for the 

runway of intended landing;

2. Description of aircraft and equipment the operator proposes to use for EFVS 

operations;

3. Applicable EFVS airworthiness documentation that indicates the EFVS was installed 

pursuant to an FAA type design approval or for foreign-registered aircraft, that the 

EFVS otherwise meets the requirements of the U.S. regulations;

4. Evidence that the applicant has reviewed and addressed the recommendations 

specified in the applicable FSB report;

5. EFVS provisions contained in the AFM/AFMS, Airplane Operations Manual (AOM), 

Flight Operations Manual (FOM), Pilot’s Operating Handbook (POH), 

QuickReference Handbook (QRH), as applicable;

6. MEL for EFVS operations and any proposed changes, if the operator seeks MEL

relief for EFVS;

7. EFVS operating procedures -- checklists, crew coordination and monitoring 

procedures, callouts, crew briefings, nonnormal operations and procedures related to 

EFVS, and special environmental considerations for EFVS, if any;

8. Proposed flightcrew training program -- PIC, Second in Command, ground, 

simulator, actual aircraft, initial, recurrent, upgrade, differences, and any other type of 

training the flightcrew will conduct;

9. Procedures and training program, as applicable, for dispatchers and other persons 

authorized to exercise operational control for EFVS operations;

10. Maintenance program, policies, procedures, and training, as applicable, for EFVS 

operations; and

11. OpSpec/MSpec/LOA sought by the operator and any proposed amendments.
07/26/13 AC 90-106A

66

10.4. Approval Process for EFVS Operations Conducted Under Part 129.

10.4.1. Foreign Air Carrier Operations in the United States. 

10.4.1.1. A foreign-registered aircraft used to conduct EFVS operations that does not have an 

FAA-type design approval must be equipped with an operable EFVS that otherwise 

meets the requirements of the U.S. regulations. That is, it must comply with all of the 

EFVS equipment requirements of the U.S. regulations, be equipped with an EFVS that 

meets § 1.1, and have the characteristics set forth in § 91.176 for the level of EFVS 

operation to be conducted (i.e., EFVS I or EFVS II).

10.4.1.2. The appropriate International Field Office (IFO) or International Field Unit (IFU) is 

responsible for authorizing Part 129 foreign air carriers for EFVS operations. This 

authorization is based primarily on an EFVS authorization from the State of the 

Operator. The major components of a foreign air carrier’s application to conduct 

EFVS operations in the United States should include: 

1. Application letter;

2. Description of aircraft and equipment proposed to be used for EFVS operations;

3. Airworthiness documentation;

4. AFM provisions for EFVS. Foreign-registered aircraft used by a foreign air 

carrier for EFVS operations within the United States must have AFM provisions 

reflecting an appropriate level of EFVS capability that meets the display, features, 

and characteristics of § 91.176;

5. MEL approval, including any EFVS provisions. (FAA-approved MEL required 

for U.S.-registered aircraft.) In accordance with § 129.14(b), no foreign air carrier 

or foreign person may operate a U.S.-registered aircraft with inoperable 

instruments or equipment unless a Master Minimum Equipment List (MMEL) 

exists for the aircraft type, and the foreign operator submits for review and 

approval its aircraft MEL, based on the MMEL, to the FAA. For EFVS 

operations, the foreign operator should take the EFVS system and components 

into consideration during MEL submission, review, and approval, if the foreign 

operator is seeking MEL relief for EFVS;

6. EFVS operational approval issued by the CAA of the State of the operator;

7. EFVS training program approval issued by the CAA of the State of the operator;

8. Maintenance program approval, including EFVS provisions. (FAA-approved 

maintenance program required for U.S.-registered aircraft.) In accordance with 

§ 129.14, “each foreign air carrier and each foreign person operating a U.S.-

registered aircraft within or outside the United States in common carriage, will 

ensure that each aircraft is maintained in accordance with a program approved by 

the Administrator.” This maintenance program must contain maintenance 
07/26/13 AC 90-106A

67

provisions for EFVS equipment; and

9. OpSpecs and any proposed amendments the operator is seeking.

10.4.1.3. U.S. and foreign regulations with respect to EFVS operations may differ. Foreign air 

carriers operating aircraft under Part 129 in the United States should be familiar with 

the equipment and operating requirements of the U.S. regulations. Additionally, 

foreign operators that expect to conduct all of the approach operations authorized by 

§ 91.176 must provide training appropriate to the approach operations to be conducted 

and must be authorized by their CAA to conduct those operations.

10.4.2. Operations of U.S.-Registered Aircraft Solely Outside the United States. EFVS 

operations conducted under Part 129 in U.S.-registered aircraft solely outside the United 

States in common carriage by a foreign person or a foreign air carrier do not require 

operational approval; however, those operations must comply with those sections of Part 

129 specified in § 129.1(b).

10.5. Waivers to Conduct EFVS Operations

10.5.1. 14 CFR §§ 91.176(a)(1)(i), 91.176(a)(2)(ii), 91.176(b)(1)(i) and (ii), and 91.176(b)(2)(ii) 

specify that no person may conduct an EFVS operation in an aircraft, except a military

aircraft of the United States, at any airport below the authorized DA/DH or MDA under 

IFR unless the aircraft is equipped with an operable EFVS that has either an FAA type 

design approval certified for EFVS operations to touchdown and rollout or an FAA type 

design approval certified for EFVS operations down to 100 feet above the TDZE. An 

operator who is conducting EFVS operations for research, development, or certification

purposes whose EFVS does not have an FAA type design approval may not descend 

below DA/DH or MDA under IFR while relying on the EFVS unless they obtain a 

certificate of waiver from the FAA to do so. 

10.5.2. 14 CFR Section § 91.903 specifies that the Administrator may issue a certificate of 

waiver authorizing the operation of aircraft in deviation from any rule listed in that 

subpart if the Administrator finds that the proposed operation can be safely conducted 

under the terms of the certificate of waiver. Section 91.905 contains a list of rules subject 

to waiver, and § 91.176, Operation below DA/DH or MDA using an enhanced flight 

vision system (EFVS) under IFR, is one of many rules listed. Operators should note that a 

certificate of waiver may not be issued for any operation conducted under 121, 125, 129, 

or 135.

10.5.3. Operators who seek a certificate of waiver must complete FAA Form 7711-2, Application 

for a Certificate of Waiver or Authorization, and submit it to the FSDO having 

jurisdiction over the area where the operator’s principal business office is located. The 

application should be submitted a minimum of 30 days before the EFVS research, 

development, or certification activity is scheduled to occur. In addition to Form 7711-2, 

the FSDO may request supporting documentation consisting of the flight test plan, test 

cards, hazard analysis and proposed mitigations, safety review board documents, 
07/26/13 AC 90-106A

68

experimental operating limitations, or other documentation necessary to process the 

application.
07/26/13 AC 90-106A

Appendix A

A-I

Appendix A. Acronyms and Abbreviations

Acronym Definition

14 CFR Title 14 of the Code of Federal Regulations

AC Advisory Circular

ACO Aircraft Certification Office

AEG Aircraft Evaluation Group

AFM Aircraft Flight Manual

AFMS Airplane Flight Manual Supplement

AFS Flight Standards Service

AIM Aeronautical Information Manual

ALS Approach Lighting System

AOM Airplane Operations Manual

ATC Amended Type Certificate

CAA Civil Aviation Authority

CAT I Category I

CAT II Category II

CAT III Category III

CFIT Controlled Flight into Terrain

CFR Code of Federal Regulations

CHDO Certificate-Holding District Office

CMU Certificate Management Unit

DA Decision Altitude

DH Decision Height

EASA European Aviation Safety Agency

EFVS Enhanced Flight Vision System

EVS Enhanced Vision System

FAA Federal Aviation Administration

FAF Final Approach Fix

FLIR Forward-Looking Infrared

FPARC Flight Path Angle Reference Cue

FPV Flight Path Vector

FOM Flight Operations Manual

FPARC Flight Path Angle Reference Cue

FPV Flight Path Vector

FSB Flight Standardization Board

FSDO Flight Standards District Office

GLS Ground Based Augmentation System [GBAS] Landing System

GMM General Maintenance Manual

GPS Global Positioning System
07/26/13 AC 90-106A

Appendix A

A-II

Acronym Definition

GS Glideslope

HAT Height Above Touchdown

HDD Head-Down Display

HUD Head-Up Display

IAP Instrument Approach Procedure

IFO International Field Office

IFR Instrument Flight Rules

IFU International Field Unit

ILS Instrument Landing System

IMC Instrument Meteorological Conditions

LDA Localizer-Type Directional Aid

LED Light-Emitting Diode

LNAV Lateral Navigation

LOA Letter of Authorization

LODA Letter of Deviation Authority

LP Localizer Performance

LPV Localizer Performance with Vertical Guidance

LVO Low Visibility Operations

MALSR Medium Intensity Approach Lighting System With Runway Alignment 

Indicator Lights

MAP Missed Approach Point

MASPS Minimum Aviation System Performance Standards

MDA Minimum Descent Altitude

MEL Minimum Equipment List

MLS Microwave Landing System

MMEL Master Minimum Equipment List

MSpec Management Specification

NAS National Airspace System

NDB Non-Directional Radio Beacon

NSP National Simulator Program

OpSpec Operations Specification

OUSD Operational Use Suitability Demonstration

PAR Precision Approach Radar

PF Pilot Flying

PIC Pilot in Command

PM Pilot Monitoring

POH Pilot’s Operating Handbook

POI Principal Operations Inspector
07/26/13 AC 90-106A

Appendix A

A-III

Acronym Definition

QRH Quick Reference Handbook

REIL Runway End Identifier Lights

RFSD Regional Flight Standards Division

RII Required Inspection Item

RNAV Area Navigation

RTS Return to Service

RVR Runway Visual Range

SCO Special Certification Office

SDF Simplified Directional Facility

SIAP Standard Instrument Approach Procedure

SIC Second in Command

SM Statute Mile

SMGCS Surface Movement Guidance and Control System

STC Supplemental Type Certificate

SVS Synthetic Vision System

TC Type Certificate

TCH Threshold Crossing Height

TDZ Touchdown Zone

TDZE Touchdown Zone Elevation

TERPS U.S. Standard for Terminal Instrument Procedures

TSO Technical Standard Order

VOR Very High Frequency Omni-Directional Range Station

VDA Vertical Descent Angle

VDP Vertical Descent Point

VFR Visual Flight Rules

VGSI Visual Glide Slope Indicator

VHF Very High Frequency

VNAV Vertical Navigation
07/26/13 AC 90-106A

Appendix B

B-I

Appendix B. Definitions

For the purpose of operations under this AC, appendix B provides the following definitions: 

1. Aircraft Certification Office (ACO). The aircraft certification directorate’s engineering 

operational element. This office administers and secures compliance with agency

regulations, programs, standards, and procedures governing the type design of aircraft, 

aircraft engines, and propellers. The office offers certification expertise on investigating and 

reporting aircraft accidents, incidents, and service difficulties. The term “ACO” refers to an 

Engine Certification Office (ECO), the Rotorcraft Certification Office (RCO), the Special 

Certification Office (SCO), the Aircraft Certification Office (ACO), and all other ACOs.

2. Aircraft Evaluation Group (AEG). A Flight Standards Service (AFS) field element that 

helps support the certification and operational suitability determinations of new and 

modified type-certificated products. AEGs are the primary AFS liaison between Flight 

Standards elements and the accountable aircraft certification directorate and/or the 

manufacturers. AEGs may be colocated with an accountable directorate or one of its 

elements.

3. Amended Type Certificate (ATC). An ATC is issued when the holder of the type 

certificate receives FAA approval to modify an aircraft design from its original design. An 

amended type certificate approves not only the modification, but also how that modification 

affects the original design.

4. Certificate-Holding District Office (CHDO). A Federal Aviation Administration (FAA) 

Flight Standards District Office (FSDO), certificate management office (CMO), 

International Field Office (IFO), or Certificate Management Unit (CMU) assigned by the 

FAA to have oversight responsibility for a particular certificate holder.

5. Enhanced Flight Vision System (EFVS). An installed aircraft system that uses an 

electronic means to provide a display of the forward external scene topography (the 

applicable natural or manmade features of a place or region especially in a way to show their 

relative positions and elevation) through the use of imaging sensors, such as FLIR, 

millimeter wave radiometry, millimeter wave radar, or low-light level image intensification.

The EFVS sensor imagery and required aircraft flight information and flight symbology is 

displayed on a HUD, or an equivalent display, on which the imagery and symbology is 

clearly visible to the PF in his or her normal position with the line of vision looking forward 

along the flight path. An EFVS includes the display element, sensors, computers and power 

supplies, indications, and controls.

6. Enhanced Flight Visibility. The average forward horizontal distance from the cockpit of an 

aircraft in flight at which a pilot using an EFVS may clearly distinguish and identify

prominent topographical objects by day or night.

7. Enhanced Flight Vision System I. The installed EFVS has been demonstrated to meet the 

criteria for AC 20-167A for EFVS I to be used for instrument approach operations from 

DA/DH or MDA down to 100 ft height above TDZ elevation.
07/26/13 AC 90-106A

Appendix B

B-II

8. Enhanced Flight Vision System II. The installed EFVS has been demonstrated to meet the 

criteria for AC 20-167A for EFVS II to be used for instrument approach and landing 

operations that rely on sufficient visibility conditions to enable unaided rollout and to 

mitigate for loss of EFVS function. An EFVS that meets the certification criteria for EFVS 

II also meets the certification criteria for EFVS I. 

9. Enhanced Vision System (EVS). An electronic means to provide the flightcrew with a 

sensor-derived or -enhanced image of the external scene (e.g., millimeter wave radar or

FLIR).

10. Flight Standardization Board (FSB). A designated group of operations inspectors who 

determine type rating, certification, and training requirements for new or modified aircraft.

11. Head-Up Display (HUD). An aircraft system that provides head-up guidance to the pilot 

during flight. It includes the display element, sensors, computers, power supplies, 

indications, and controls. It may receive inputs from an airborne navigation system or flight 

guidance system. This system allows the pilot to look for the outside visual references in the 

same location as they appear in the EFVS image.

12. Head-Down Display (HDD). A display or suite of displays that provide control, 

performance, and navigation information that is presented to the pilot on conventional headdown instrumentation, or integrated electronic flight displays. 

13. Glide Slope. Vertical guidance for an aircraft during approach and landing.

14. Master Minimum Equipment List (MMEL). A list of equipment that the FAA has 

determined may be inoperative under certain operational conditions and still provide an 

acceptable level of safety. The MMEL contains the conditions, limitations, and procedures 

required for operating the aircraft with these items inoperative. The MMEL is used as a 

starting point in the development and review of an individual operator’s minimum 

equipment list (MEL). 

15. Minimum Equipment List (MEL). The MEL is a list derived from the MMEL for a 

particular make and model of aircraft by an individual operator. The operator’s MEL takes 

into consideration the operator’s particular aircraft configurations, operating procedures, and 

conditions with certain inoperative equipment. 

16. Natural Vision. The means by which a pilot observes objects without benefit of any visionenhancing technology (except personal corrective lenses). 

17. Nonprecision Approach Procedure. A standard instrument approach procedure (IAP) for

which no electronic glideslope (GS) information is provided. 

18. Precision Approach Procedure. A standard instrument approach procedure (SIAP) for 

which an electronic GS information is provided, such as instrument landing system (ILS) 

and precision approach radar (PAR). 
07/26/13 AC 90-106A

Appendix B

B-III

19. Special Instrument Approach Procedure. An IAP authorized for use only by an air carrier 

or some other segment of the aviation industry that is not published in the Federal Register 

and identified as a “Special Procedure.” Special Procedures may be developed for public or 

private use based on aircraft performance, aircraft equipment, or crew training, and may

require the use of landing aids, communications, or weather services not available for public 

use. 

20. Standard Instrument Approach Procedure (SIAP). An IAP promulgated under Title 14 

of the Code of Federal Regulations (14 CFR) part 97. 

21. Straight-In Nonprecision Approach. An approved IAP in which the final approach course 

alignment and descent gradient permits authorization of straight-in landing minima. The 

angle of convergence of the final approach course and the extended runway centerline will 

not exceed 30 degrees (15 degrees for Area Navigation (RNAV)/global positioning system 

(GPS)) and the point of intersection will normally be within 5,200 feet outward from the 

runway threshold. The maximum descent gradient is 400 ft/NM. 

22. Straight-In Precision Approach. An approved IAP in which the final approach course 

alignment does not exceed 3 degrees of the extended runway centerline. 

23. Supplemental Type Certificate (STC). An STC is issued for a major design change to a 

type certificate (TC) when the change is not so extensive as to require application for a new 

TC, except that the holder of a TC for a product may apply for amendment of the original 

TC. 

24. Synthetic Vision. A computer-generated image of the external scene topography from the 

perspective of the flightdeck that is derived from aircraft attitude, high-precision navigation 

solution, database of terrain, obstacles, and relevant cultural features. 

25. Synthetic Vision System (SVS). An electronic means to display a synthetic vision image of 

the external scene topography to the flight crew. An SVS display does not provide an 

independent, real-time source of forward scene information.

26. Type Certificate (TC). A design approval that certifies that an applicant’s design for a new 

(or new model) aircraft, engine, or propeller meets the minimum FAA requirements. It 

includes the type design, the operating limitations, the type certificate data sheet, the 

applicable regulations the type design was certified to, and any other conditions or 

limitations required in 14 CFR, Subchapter C.

27. Touchdown Zone (TDZ) Elevation (TDZE). The highest elevation in the first 3,000 feet of 

the landing surface. TDZE is indicated on the IAP chart when straight-in landing minimums 

are authorized. 
C-I

Appendix C. Related Publications

C-1. Related Publications. 

a. Federal Aviation Administration Documents:

1. AC 20-167, Airworthiness Approval of Enhanced Vision System, Synthetic Vision 

System, Combined Vision System, and Enhanced Flight Vision System Equipment

2. AC 25-11A, Electronic Flight Deck Displays

3. AC 91-16, Category II Operations General Aviation Airplanes

4. AC 120-28, Criteria for Approval of CAT III Weather Minima for Takeoff, Landing, 

and Rollout

5. AC 120-29, Criteria for Approval of Category I and Category II Weather Minima for 

Approach

6. AC 120-57, Surface Movement Guidance and Control System

7. AC 120-71, Standard Operating Procedures for Flight Deck Crewmembers

8. AC 120-76, Guidelines for the Certification, Airworthiness, and Operational 

Approval of Electronic Flight Bag Computing Devices

9. FAA Order 8000.94, Procedures for Establishing Airport Low-Visibility Operations 

and Approval of Low-Visibility Operations/Surface Movement Guidance and Control 

System Operations

10. FAA Order 8900.1, Flight Standards Information Management System (FSIMS)

11. Flight Standardization Board (FSB) reports: 

http://fsims.faa.gov/PICResults.aspx?mode=Publication&doctype=FSB%20Reports.

12. National Simulator Program (NSP) information: 

http://www.faa.gov/about/initiatives/nsp/.

NOTE: You may obtain ACs and Policy Memorandums by clicking on the 

link “Regulatory and Guidance Library” on the FAA public Web site: 

http://www.faa.gov/.

b. RTCA, Inc. Documents

1. DO-315, Minimum Aviation System Performance Standards (MASPS) for Enhanced 

Vision Systems, Synthetic Vision Systems, Combined Vision Systems, and Enhanced 

Flight Vision Systems.
07/07/13 AC 90-106A

Appendix F

C-II

2. DO-341, Minimum Aviation System Performance Standards (MASPS) for an 

Enhanced Flight Vision System to Enable All-Weather Approach, Landing and RollOut to a Safe Taxi Speed

c. Society of Automotive Engineers (SAE) International.

1. AS 5703, Minimum Performance Standard for Enhanced Vision System.

2. AS 8055, Minimum Performance Standard for Airborne Head Up Display (HUD).

C-2. How to Get Publications.

a. Order copies of 14 CFR, parts from the Superintendent of Documents, Government 

Printing Office, P.O. 979050, St. Louis, MO 63197. For general information, telephone (202) 

512-1800 or fax (202) 512-2250. You can order copies online at www.access.gpo.gov. Select 

“Access” then “Online Bookstore.” Select “Aviation,” then “Code of Federal Regulations.”

b. Order copies of FAA advisory circulars from the U.S. Department of Transportation, 

Subsequent Distribution Office, M-30, Ardmore East Business Center, 3341 Q 75th Avenue, 

Landover, MD 20785. You can also get copies from our FAA website at www.airweb.faa.gov or 

www.faa.gov.

c. You can find a current list of technical standard orders on the FAA Internet website 

Regulatory and Guidance Library at www.airweb.faa.gov/rgl. You will also find the Technical 

Standard Order (TSO) Index of Articles at the same site.

d. Order copies of RTCA documents from RTCA, Inc., 1828 L St., NW, Suite 805, 

Washington, DC 20036, telephone (202) 833-9339, Fax (202) 833-9434, or website:

www.rtca.org.

e. Order copies of SAE documents from SAE World Headquarters, 400 Commonwealth 

Drive, Warrendale, PA 15096-0001, USA, telephone: (877) 606-7323, or website:

http://www.sae.org.