U.S. Department of Transportation Federal Aviation Administration Advisory Circular Subject: Enhanced Flight Vision Systems Date: 3/2/17 AC No: 90-106A Initiated by: AFS-400 Change:
This advisory circular (AC) provides information about using an enhanced flight vision system (EFVS) in lieu of natural vision while conducting instrument approach operations. It addresses dispatching and releasing aircraft for EFVS operations and explains the requirements for conducting EFVS operations to 100 feet above the touchdown zone elevation (TDZE) and EFVS operations to touchdown and rollout. This AC also explains how to obtain an operations specification (OpSpec), management specification (MSpec), or letter of authorization (LOA) to conduct those EFVS operations that require an approval.
We have made every attempt to write EFVS regulations that are performance based and not limited to a specific sensor technology. The regulations accommodate future growth in real-time sensor technologies used in most EFVSs and maximize the benefits of rapidly evolving instrument approach procedures (IAP) and advanced flight deck technology to increase safety and access during low-visibility operations.
ORIGINAL SIGNED by /s/ John Barbagallo Deputy Director, Flight Standards Service
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CONTENTS Paragraph Page
1 Introduction1
1.1 Purpose1
1.2 Cancellation1
1.3 Applicability1
1.4 Scope1
1.5 Transition Period3
2 Regulatory Background, Definitions, and Types of EFVS Operations3
2.1 EFVS Regulatory Background3
2.2 Definition of an EFVS5
2.3 Purpose of an EFVS5
Figure 1. View During an Approach with EFVS (Left) and Without
EFVS (Right)6
2.4 Definition of an EFVS Operation6
2.5 Types of EFVS Operations6
Figure 2. Operational Concept for an EFVS Operation to Touchdown
and Rollout7
Figure 3. Operational Concept for an EFVS Operation to 100 Feet Above
the Touchdown Zone Elevation8
3 Flight Planning and Beginning or Continuing an Approach Under IFR Using
EFVS-Equipped Aircraft8
3.1 Flight Planning for Parts 91 and 91K Operators8
3.2 Flight Planning for Parts 121, 125, and 135 Operators8
4 EFVS Operational Concepts9
4.1 EFVS Operations to Touchdown and Rollout (§ 91.176(a))9
Table 1. Required Visual References15
4.2 EFVS Operations to 100 Feet Above the TDZE (§ 91.176(b))16
4.3 Considerations for EFVS Operations22
4.4 EFVS Operations Conducted by Public Aircraft Operators26
4.5 EFVS Operations Conducted for the Purpose of Research and Development
or Showing Compliance With Regulations26
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5 Pilot Training Requirements for EFVS Operations26
5.1 Regulatory Requirement for Training26
5.2 EFVS Ground Training27
5.3 EFVS Flight Training31
5.4 Supplementary EFVS Training33
5.5 EFVS Recurrent Training33
5.6 Other Requirements and Considerations Pertaining to EFVS Training33
5.7 Military Pilots and Former Military Pilots in the U.S. Armed Forces34
5.8 Public Aircraft Operators34
5.9 Credit for Previous Training and Transition Period for Complying With the
Training Requirements of § 61.6634
5.10 Exceptions to the EFVS Training Requirements in § 61.6635
5.11 Requirements for FFSs Used to Provide EFVS Training36
6 Recent Flight Experience, Proficiency Check, Competency Check, and Refresher
Training Requirements for EFVS Operations36
6.1 EFVS Recent Flight Experience and Refresher Training Requirements for
Part 91 Operators (Other Than Part 91K Operators)36
6.2 Proficiency Check and Competency Check Requirements for Operators
Conducting EFVS Operations Under Part 91K, 121, 125, or 13538
6.3 Using a Proficiency Check From the U.S. Armed Forces to Satisfy the Recent
Flight Experience Requirements of § 61.66(f)39
6.4 Public Aircraft Operators39
6.5 Transition Period for Complying With the Recent Flight Experience and
Refresher Training Requirements of § 61.6639
6.6 Use of an FFS to Meet the Recent Flight Experience Requirements of § 61.6640
7 Training for Dispatchers and Other Persons Authorized to Exercise Operational
Control for EFVS Operations40
7.1 Dispatch, Flight Release, and Flight Following Considerations40
7.2 Initial Training for Dispatchers and Other Persons Authorized to Exercise
Operational Control40
7.3 Recurrent and Differences Training for Dispatchers and Other Persons
Authorized to Exercise Operational Control42
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8 Aircraft Qualification and Maintenance Program Requirements42
8.1 General42
8.2 Applicability42
8.3 Aircraft Qualification Requirements43
8.4 Maintenance Requirements43
9 Maintenance Training for EFVS Operations45
9.1 Maintenance Training45
10 Operational Approval Process for EFVS Operations46
10.1 Approval Process Overview46
10.2 Authorizations to Conduct EFVS Operations46
10.3 Application to Conduct EFVS Operations47
10.4 Observing and Evaluating the Operator’s Ability to Perform EFVS
Operations49
10.5 Approval Process for EFVS Operations Conducted by Operators of
Foreign-Registered Aircraft under Part 12951
10.6 Waivers From § 91.17653
11 AC Feedback Form53
Appendix A. Acronyms and AbbreviationsA-1
Appendix B. DefinitionsB-1
Appendix C. Related Regulations and GuidanceC-1
1 1 INTRODUCTION.
1.1 Purpose. This advisory circular (AC) provides flight planning, operational, training, and recent flight experience guidance for enhanced flight vision system (EFVS) approach operations. For those operations that require a specific approval from the Federal Aviation Administration (FAA), it explains how to obtain an operations specification (OpSpec), management specification (MSpec), or letter of authorization (LOA) to conduct EFVS operations.
1.2 Cancellation. AC 90-106, Enhanced Flight Vision Systems, dated June 2, 2010, is canceled.
1.3 Applicability. This AC applies to all operators using EFVSs to conduct approach operations. This AC also applies to operators who dispatch or release a flight under Title 14 of the Code of Federal Regulations (14 CFR) part 121, release a flight under 14 CFR part 125, or take off under instrument flight rules (IFR) under 14 CFR part 135 for the purpose of conducting an EFVS operation. In addition, this AC applies to EFVS-equipped part 121, 125, or 135 operators who are permitted to begin or continue an approach for the purpose of conducting an EFVS operation when the destination airport weather is below the visibility minimums prescribed for the instrument approach procedure (IAP) to be flown.
Note: The International Civil Aviation Organization (ICAO) and other foreign Civil Aviation Authorities (CAA) 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 pilots use in lieu of natural vision to conduct certain specified operations. You should not confuse the term “EVS” in this context with an EVS that is not permitted to be used in lieu of natural vision to descend below decision altitude (DA)/decision height (DH) or minimum descent altitude (MDA) (see paragraph 1.4.4).
1.4 Scope.
1.4.1 This AC describes acceptable means, but not the only means, for an operator to obtain authorization to conduct EFVS operations. This AC does not alter regulatory requirements.
1.4.2 The paragraphs in this AC provide information on the following subject areas:
1. Regulatory background of EFVS operations;
2. Types of EFVS operations;
3. Concept of operation associated with each type of EFVS operation;
4. Equipment required by the operating rule to conduct EFVS operations;
5. Enhanced flight visibility, visual reference, and other operational requirements for conducting EFVS operations;
6. Training, recent flight experience, refresher training, proficiency check, and competency check requirements for EFVS operations;
7. Provisions that permit part 121, 125, or 135 operators using EFVS-equipped aircraft to dispatch, release a flight, or take off under IFR for the purpose of conducting an EFVS operation;
8. Parts 121, 125, and 135 requirements for initiating and continuing an approach for the purpose of conducting an EFVS operation when the visibility is less than the visibility minimums prescribed for the IAP to be flown;
9. Maintenance requirements;
10. Exceptions to certain EFVS operating requirements of 14 CFR part 91, § 91.176 and certain EFVS pilot requirements of 14 CFR part 61, § 61.66;
11. Compliance dates;
12. EFVS requirements pertaining to public aircraft operations; and
13. How to obtain an OpSpec/MSpec/LOA to conduct EFVS operations that require an approval.
1.4.3 For simplicity, because the EFVS training, qualification, and recency-of-experience requirements are contained in parts 61, 135, and appendices F and H to part 121, the terminology used in this AC is consistent with those regulations. Air carriers with an Advanced Qualification Program (AQP) should use the content of this AC in conjunction with AC 120-54, Advanced Qualification Program.
1.4.4 This AC does not address the use of an EVS which does not meet the requirements necessary to be considered an EFVS (see paragraph 4). 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 may present a sensor image on a head-down display (HDD), but it may not be able to present the sensor 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 operating requirements for EFVS under § 91.176; § 91.1039; part 121, § 121.651;
part 125, § 125.381; or part 135, § 135.225. Consequently, a pilot cannot use an EVS in lieu of natural vision to descend below DA/DH or MDA.
1.4.5 This AC does not address the use of Synthetic Vision Systems (SVS) or synthetic vision guidance systems (SVGS). Unlike an EFVS, an SVS does not provide a real-time sensor image of the outside scene and does not meet the requirements for EFVS operations.
A pilot, therefore, cannot use a synthetic vision image on an HDD or HUD in lieu of natural vision to descend below DA/DH or MDA.
1.4.6 An EFVS can be integrated with SVS, also known as a combined vision system (CVS).
Such a system can be used to conduct EFVS operations if all of the requirements for an EFVS are satisfied and the SVS image does not interfere with the pilot’s ability to see the external scene, to identify the required visual references, or to see the sensor image.
1.5 Transition Period. March 21, 2017 to March 13, 2018.
1.5.1 Prior to December 13, 2016, the regulations for EFVS operations to 100 feet above the touchdown zone elevation (TDZE) were located in § 91.175(l) and (m). The EFVS final rule published on December 13, 2016 revised these regulations and moved them to § 91.176(b). To provide an adequate transition period for operators to comply with the new requirements of § 91.176(b), § 91.175(n) permits operators conducting EFVS operations to 100 feet above the TDZE to comply with either § 91.175(l) and (m) or § 91.176(b) prior to March 13, 2018. The requirements of § 91.175(l) and (m) will expire on March 13, 2018. Beginning on this date, operators who conduct EFVS operations to 100 feet above the TDZE must comply with § 91.176(b) and the requirements of § 61.66.
Operators are encouraged to comply with § 91.176(b) and § 61.66 as soon as practicable within the transition period.
1.5.2 Operators who have an OpSpec, MSpec, or LOA to conduct EFVS operations under § 91.175(l) must be issued a new authorization under § 91.176(b) to continue operations beyond the transition period. Part 121, 125, or 135 operators who obtain a new authorization may request provisions for dispatch, flight release, or takeoff under IFR to be added to their authorizations. They may also request provisions to be added to their authorizations for beginning or continuing an approach when the reported visibility is less than the visibility minimums prescribed for the IAP to be flown. Paragraph 10.2 provides additional information on how to obtain this authorization.
1.5.3 The transition period also provides authorized training providers with adequate time to revise or develop training programs that meet the training requirements for EFVS operations. Paragraphs 5 and 6 contain additional information pertaining to training, recent flight experience, and proficiency requirements for EFVS operations.
2 REGULATORY BACKGROUND, DEFINITIONS, AND TYPES OF EFVS OPERATIONS.
2.1 EFVS Regulatory Background.
2.1.1 The requirements for operating below DA/DH or MDA under IFR 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 (refer to § 91.175(c)). On January 9, 2004, the FAA published a final rule in the Federal Register (FR), 69 FR 1620, Enhanced Flight Vision Systems. The rule permitted EFVSs to be used in lieu of natural vision to continue descending below DA/DH or MDA to 100 feet above the TDZE on an IAP that is flown using published straight-in landing
4 minimums other than Category (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 December 13, 2016, the FAA published a final rule in the FR, 81 FR 90126, Revisions to Operational Requirements for the Use of Enhanced Flight Vision Systems (EFVS) and to Pilot Compartment View Requirements for Vision Systems. The revised rule permits a pilot to use an EFVS in lieu of natural vision to continue descending below 100 feet to touchdown and rollout under certain conditions. This final rule also amended the visual reference requirements for both 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 a pilot to use EFVS in lieu of natural vision to descend below DA/DH to touchdown and rollout, the 2016 final rule contained other amendments that affect EFVS operations. The FAA amended the definition of EFVS in 14 CFR part 1, § 1.1 to more precisely describe an EFVS and added a definition for EFVS operation.
The FAA also addressed provisions that permit operators who conduct EFVS operations under part 121, 125, or 135 to use EFVS-equipped aircraft to dispatch, release, or take off under IFR. It also specified the conditions under which a part 121, 125, or 135 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 ground and flight training and establish recent flight experience and refresher training requirements. It also amended the proficiency check and competency check requirements of §§ 91.1065, 125.287, and 135.293, and appendix F to part 121 to include tasks appropriate to the EFVS operations the certificate holder is authorized to conduct. 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.
2.1.4 Finally, the 2016 final rule consolidated all of the EFVS requirements in part 91 into new § 91.176. The FAA moved and restructured the regulations for EFVS operations to 100 feet that were located in § 91.175(l) and (m) to § 91.176.
2.1.5 It is important to understand that the EFVS regulations contained in § 91.176 do not specify visibility limitations. Part 91 operators (other than part 91 subpart K (part 91K)) may conduct EFVS approach operations to 100 feet above the TDZE without any specific approval. For all other operations, the EFVS regulatory framework enables the FAA to approve and manage EFVS operations to an appropriate visibility based on the demonstrated capability of the EFVS equipment and an operator’s ability to perform the EFVS operations for which they seek specific approval. This regulatory framework permits the FAA to specify visibility and other operating conditions and limitations through an operator’s OpSpec/MSpec/LOA for EFVS operations.
2.2 Definition of an EFVS. Imaging-sensor technologies can offer significant advantages in both safety and capability for low-visibility flight operations. Section 1.1 defines an EFVS as “…an installed aircraft system which uses an electronic means to provide a display of the forward external scene topography (the 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, including but not limited to forward-looking infrared, millimeter wave radiometry, millimeter wave radar, or low-light level image intensification. 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 or equivalent display 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. 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, View During an Approach with EFVS (Left) and Without EFVS (Right)). Combining the flight information, navigation guidance, and sensor imagery on a HUD or equivalent display allows the pilot to continue looking forward along the flightpath 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.
Use of an EFVS may improve safety by enhancing situation and position awareness, providing visual cues to maintain a stabilized approach, and minimizing missed approaches. 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.
6 Figure 1. View During an Approach with EFVS (Left) and Without EFVS (Right)
(Images courtesy of the National Aeronautics and Space Administration (NASA) Langley Research Center.)
2.4 Definition of an EFVS Operation. Sections 91.175(c) and 91.176(a) and (b) specify 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) and (b). Section 1.1 of the regulations defines an EFVS operation as “an operation in which visibility conditions require an EFVS to be used in lieu of natural vision to perform an approach or landing, determine enhanced flight visibility, identify required visual references, or conduct a rollout.” This definition establishes the conditions under which an EFVS is required to conduct specific operations.
2.5 Types of EFVS Operations.
2.5.1 There Are Two Types of EFVS Approach Operations:
2.5.1.1 EFVS Operations to Touchdown and Rollout. An EFVS operation to touchdown and rollout 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 or DH to touchdown and rollout (see Figure 2, Operational Concept for EFVS Operation to Touchdown and Rollout). These operations may be conducted only on IAPs that have a DA or DH. You can find the regulations for EFVS operations to touchdown and rollout in § 91.176(a).
An operator’s OpSpec/MSpec/LOA to conduct EFVS operations to touchdown specifies a visibility minimum for the operation, based on the demonstrated performance of their system. This AC describes a method to demonstrate the ability to conduct EFVS operations to touchdown in visibilities down to Runway Visual Range (RVR) 1,000 feet. Operators may demonstrate improved performance and obtain authorization to conduct EFVS operations in even lower visibilities provided their airworthiness approval is appropriate for the EFVS operation to be conducted. Paragraph 4.1 contains
7 additional information about EFVS operations to touchdown and rollout and associated EFVS requirements.
Figure 2. Operational Concept for an EFVS Operation to Touchdown and Rollout
Photo obtained from Google Earth.
2.5.1.2 EFVS Operations to 100 feet Above the TDZE. An EFVS operation to 100 feet above the TDZE 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 (see Figure 3, Operational Concept for an EFVS Operation to 100 Feet Above the Touchdown Zone Elevation). Natural vision must be used to descend below 100 feet above the TDZE. These operations may be conducted on IAPs that have a DA/DH or MDA. You can find the regulations for EFVS operations to 100 feet above the TDZE in § 91.176(b). Paragraph 4.2 contains additional information about EFVS operations to 100 feet above the TDZE and associated EFVS requirements.
8 Figure 3. Operational Concept for an EFVS Operation to 100 Feet Above the Touchdown Zone Elevation
Photo obtained from Google Earth.
3 FLIGHT PLANNING AND BEGINNING OR CONTINUING AN APPROACH UNDER IFR USING EFVS-EQUIPPED AIRCRAFT.
3.1 Flight Planning for Parts 91 and 91K Operators. Flight planning for the purpose of conducting an EFVS operation is the same as flight planning for any other approach and must consider the forecast weather at the destination. The fuel requirements for flight in IFR conditions specified in § 91.167 apply to EFVS operations.
3.2 Flight Planning for Parts 121, 125, and 135 Operators. To minimize the potential of not being able to visually acquire the runway and complete an approach during poor visibility conditions, part 121, 125, and 135 operators are prohibited from beginning or continuing an approach procedure when the reported visibility is less than that prescribed for the instrument approach (refer to §§ 121.651, 125.325, 125.381, and 135.225).
To minimize the risk of diverting, these operators also can only dispatch a flight, release a flight or takeoff under IFR when the forecast weather is at or above the authorized minimums at the estimated time of arrival at the airport or airports to which the operator has been dispatched or released (refer to §§ 121.613, 125.361, and 135.219). This same operating principle applies to EFVS operations. A part 121, 125, or 135 operator may dispatch a flight, release a flight, or take off under IFR for the purpose of conducting an EFVS operation when the forecast weather is at or above the authorized EFVS operational minimums at the estimated time of arrival at the airport or airports to which the operator has been dispatched or released. Therefore, they can be reasonably assured