Advisory Circular Subject: Enhanced Flight Vision Systems Date: DD/MM/YY Initiated by: AFS-400 AC No: 90-EFVS 1. PURPOSE. This advisory circular (AC) provides information to an applicant pursuing airworthiness certification and operational approval of an enhanced flight vision system (EFVS). It is an acceptable, but not the only means, of obtaining airworthiness certification and operational approval. 2. APPLICABILITY. This AC applies to persons operating aircraft under Title 14 of the Code of Federal Regulations 14 (CFR) parts 91, 121, 125, and 135. A pilot may use an EFVS for Category I straight-in approach operations below decision height (DH) or minimum descent altitude (DA) under 91.175(l) and (m). 3. RELATED REFERENCES. a. Title 14 CFR References. This AC applies to: (1) Part 21. (2) Part 23. (3) Part 25, 25.562, 25.773, 25.777, 25.1301, 25.1303, 25.1309, 25.1316, 25.1321, 25.1333, 25.1381, 25.1541, 25.1542. (4) Part 91, 91.175(l) and (m) and subpart K. (5) Part 119, subpart C. (6) Part 121, 121.651. (7) Part 125, 125.31 35, 125.381. (8) Part 129, 129.11. (9) Part 135, 135.225. b. Related Reading Materials (current editions).
AC 90-EFVS DRAFT DATE (1) AC 23.1311-1, Installation of Electronic Displays in Part 23 Airplanes. (2) AC 25-11, Transport Category Airplane Electronic Display Systems. (3) AC 25.773-1, Pilot Compartment View Design Considerations. (4) AC 25.1309-1, System Design and Analysis. (5) AC 120-28, Criteria for Approval of CAT III Weather Minima for Takeoff, Landing, and Rollout, Appendix 2, Airworthiness Approval of Airborne Systems Used during a Takeoff in Low Visibility Weather Conditions. (6) AC 120-29, Criteria for Approval of Category I and Category II Weather Minima for Approach. (7) AC 120-71, Standard Operating Procedures for Flight Deck Crewmembers. NOTE: ACs and Policy Statements may be obtained by clicking on the link Regulatory and Guidance Library on the FAA public Web site: http:// www.faa.gov/avr/arm. (8) FAA Policy Memorandum PS-ANM100-1992-00057, Airspeed Displays for Electronic Flight Instruments Systems (EFIS), 25 February 1992. (9) PS-ANM100-1996-00056, Low and High Speed Awareness Cues for Linear Tape Airspeed Displays, 12 September 1996. (10) Society of Automotive Engineers (SAE) Aerospace Standard 8055, Minimum Performance Standard for Airborne Head up Display, March 1999. (11) SAE Aerospace Recommended Practice (ARP) 5288, Transport Category Airplane Head-up Display, May 2001. (12) SAE Aerospace Recommended Practice (ARP) 4256A, Design Objectives for Liquid Crystal Displays for Part 25 (Transport) Aircraft. (13) RTCA DO-178B, Software Considerations in Airborne Systems and Equipment Certifications. 4. BACKGROUND. a. For many years 91.175 prescribed flight visibility requirements using the pilot s natural vision to identify the approach lights and the runway environment when operating an aircraft under instrument flight rules (IFR). Until Amendment 91-281 (69 FR 1620, January 9, 2004) [Docket Number FAA-2003-14449], 91.175 did not allow descents and landings if the pilot could not see certain required visual references with his/her natural vision. Page 2 Par 3
DATE DRAFT AC 90-EFVS Par 3 Page 3
b. Amendment 91-281 revised 91.175 to allow a pilot to fly a straight-in landing, Standard Instrument Approach Procedure (SIAP) using a FAA-certificated EFVS. An EFVS uses imaging-sensor technologies to provide a real-time enhanced image of the external topography to the pilot. This revision of the regulations allows a pilot to use an EFVS to identify the required visual references to verify proper runway alignment, and to descend from the decision altitude/height, or minimum descent altitude (MDA), to 100 feet above the touchdown zone (TDZ) elevation of the runway of intended landing, when the runway environment is not visible using the pilot s natural vision. To descend below 100 feet above the TDZ elevation of the runway of intended landing, however, the pilot must be able to see the visual references required by 91.175 with his/her natural vision. 5. AIRWORTHINESS CERTIFICATION OF EFVS. a. FR Amendment 91-281 focused on the requirements for operational approval of EFVS. All EFVS equipment installations must also meet the airworthiness certification requirements in parts 21, 23, 25, 27, and 29 (as applicable). An FAA approval of an EFVS consists of both an airworthiness approval and an operational approval before the pilot may use EFVS under the revised 91.175. b. In 2001 the FAA issued Special Condition No. 25-180-SC (66 FR 32717, June 18, 2001) for the airworthiness certification of an EFVS on the Gulfstream Model G-V airplane. Under the authority of 21.16, the FAA Administrator made the finding that the regulations applicable to pilot compartment view do not contain adequate or appropriate safety standards for the airworthiness certification of EFVS. The airworthiness certification regulation addressed in that special condition was 25.773; however, similar regulations are found at 14 CFR 23.773, 27.773, and 29.773. c. Section 25.773 establishes requirements for the pilot compartment view that may conflict with the display of EFVS imagery. Amendment 91-281 did not terminate the need for both the applicant and the FAA to address the FAA s 2001 21.16 finding with respect to 25.773. Therefore, the FAA must issue special conditions that provide for an equivalent level of safety to 25.773 for each aircraft model with an EFVS installed. The applicant for airworthiness certification approval must have their proposed EFVS equipment and installation evaluated under airworthiness criteria similar in scope to that contained in Special Condition No. 25-180-SC. The FAA will issue appropriate special conditions for each aircraft model that will require the combination of what the pilot sees in, through, and around the EFVS image to be as safe and effective for all pilot tasks requiring the outside view, as they would be if the EFVS image were not displayed at all. d. Until the FAA undertakes general rulemaking to revise 25.773 to provide appropriate Airworthiness Certification Standards for EFVS, an applicant must receive from the FAA their own special conditions for their EFVS installation on a particular model aircraft and expect the FAA to publish a special condition based on their EFVS application.
DATE DRAFT AC 90-EFVS e. Appendices 3 and 4 to this AC contain guidance on the airworthiness certification issues that may be raised by the FAA during the airworthiness certification of an applicant s EFVS. These appendices are based on the special conditions issued for the Gulfstream Model G-V airplane and FAA experience in the issuance of that supplemental type certificate. The appendices are general in nature and an applicant s special conditions may necessitate additional or other requirements depending on the complexities of each aircraft model and EFVS installation. The applicant should use the information in this AC in preparing for their meetings with the FAA in pursuing their own Supplemental Type Certificate (STC) for EFVS. 6. OPERATIONAL USE of EFVS UNDER REVISED 91.175. a. Section 91.175(l) and (m) provides the regulatory authorization for operators conducting straight-in IAPs other than Category II or Category III to operate below the DH and MDA when using a FAA certified EFVS to obtain a real-time image of the external topography. b. The EFVS provides a means for the pilot to achieve enhanced flight visibility, positively identify visual references for Category I approach operations, and to continue a standard instrument approach procedure below the DH or MDA down to 100 feet above the TDZ elevation of the runway of intended landing. At that point and below, the lights or markings of the runway threshold or the lights or markings of the TDZ would have to be visible to the pilot without using the EFVS in order for the aircraft to proceed to a landing. c. During some reduced visibility conditions, an EFVS can display imagery that may significantly improve the pilot s capability to detect objects, such as approach lights and visual references of the runway environment, aircraft, vehicles, and animals encroaching on the runway in use that may not otherwise be visible using natural vision. Pilots using an EFVS should be careful not to conclude that the flightpath is free of hazards merely because none are visible in the image. In some situations, imaging sensor performance can be variable and unpredictable. d. Approach Minima. Using an EFVS for approach to straight-in landing operations below DH or MDA is authorized under 91.175 (l) and (m), which addresses Category I operations only. The use of an EFVS does not alter the minima for ceiling and flight visibility required for a SIAP. For Category II and Category III operations, the operator must comply with the aircraft equipment and training requirements set forth for Category II and Category III operations which require more precise path performance and integrity to mitigate the low visibility conditions. For Category II or Category III operations conducted under parts 91 subpart K, 121, 125, 129, and 135, the letter of authorization (LOA), or management specifications (MSpecs), or operations specifications (OpSpecs) must state that the use of EFVS imagery is authorized. Par 6 Page 5
AC 90-EFVS DRAFT DATE e. Takeoff. Takeoff at minima lower than that prescribed by the regulations must be approved on a case-by-case basis. For questions regarding takeoff at lower than prescribed minima, contact AFS-400, Flight Technologies and Procedures Division. f. Situation Awareness. Use of an EFVS with a head-up display (HUD) may improve the level of safety by improving situation and position awareness, providing visual cues to maintain a stabilized approach, and minimizing missed approach situations. In addition to using an EFVS to satisfy requirements of 91.175(l), 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 observe potential runway incursions during ground operations in reduced visibility conditions. Even in situations where required flight visibility under 91.175(c)(2) exists at the DH or MDA, an EFVS may provide useful visual cues for enhanced situation awareness. 7. CATEGORY I OPERATING PROCEDURES. a. Basic Strategy Using EFVS. At the MDA or DH, lacking visual acquisition of the runway environment by natural vision (see 91.175(c)), the pilot may use the EFVS to continue the approach to 100 feet above the TDZ elevation, if certain conditions exist. (1) Continuing an Approach Below MDA or DH Using EFVS. If the pilot determines that the enhanced flight visibility is not less than the minimum visibility prescribed in the IAP being flown, and the pilot acquires the required visual imagery references prescribed in 91.175(l)(3), then the pilot can continue the approach to 100 feet above the TDZ. To continue the approach, the pilot uses the EFVS imaging to visually acquire the runway environment (the approach light system, if installed, or both the runway threshold and the TDZ), confirm lateral alignment, maneuver to the extended runway centerline earlier (higher and farther out from the runway) than would otherwise be possible, and continue a normal descent from the MDA or DH to 100 feet above the TDZ. (2) Maintaining the Vertical Path Below MDA or DH Using EFVS. The flightpath angle (FPA) reference cue and the flight path vector (FPV) with the EFVS imagery of the TDZ provide the primary vertical path reference for the pilot when vertical guidance provided by navigation aids such as an instrument landing system (ILS), microwave landing system (MLS), or lateral navigation/vertical navigation (LNAV/VNAV) is not available. b. When to Go-Around. The pilot should execute a missed approach procedure under the conditions described below. (1) Commencing the Approach. Any pilot operating an aircraft with an EFVS installed should be aware that the missed approach requirements of 91.175(c), using natural vision, and 91.175(l), using EFVS to achieve enhanced flight visibility, are different. A pilot would, therefore, first have to determine whether an approach will be Page 6 Par 6
DATE DRAFT AC 90-EFVS commenced using natural vision in accordance with 91.175(c) or using EFVS in accordance with 91.175(l). Once that decision is made, different requirements determine when a missed approach must be executed. If a pilot chooses to conduct an approach without an EFVS using natural vision under 91.175(c), that pilot would follow the decisionmaking process specified in 91.175(c) for operating below DH or MDA. If the pilot cannot meet those requirements, a missed approach must be executed. If a pilot chooses to conduct an approach using an EFVS under 91.175(l), that pilot would follow the decisionmaking process specified in 91.175(l) for operating below DH or MDA. If the pilot cannot meet those requirements, a missed approach must be executed. The missed approach procedure published on the approach charts would remain the same whether an approach is conducted using natural vision or conducted using an EFVS, but the requirements of 91.175(c)(1) through (3) are not the same as those of 91.175(l)(1) through (4). Consequently, while these two sets of requirements provide a parallel decisionmaking process, the requirements for when a missed approach must be executed differ. (2) At or Below MDA or DH. The pilot must initiate a missed approach whenever he or she determines that: (a) The flight, or enhanced flight visibility is less than the visibility minima prescribed in the IAP being used; (b) The minimum required visual references for the runway of intended landing are no longer distinctly visible and identifiable to the pilot using either natural vision ( 91.175(c)(3)) or EFVS imagery ( 91.175(l)(3)); or (c) The aircraft is not in a position to land safely. For an operation conducted under part 121 or part 135, an appropriate missed approach procedure would have to be executed immediately if the pilot were unable to control the descent rate of the aircraft to allow touchdown to occur within the TDZ of the intended landing. (3) At or less than 100 Feet Above TDZ Elevation. At or less than 100 feet above the TDZ elevation, the rule does not require the EFVS to be turned off in order to continue to a landing without reliance on the EFVS sensor image. A pilot may continue the approach using the EFVS as long as the required visual references can be seen through the HUD using natural vision. Otherwise, a missed approach must be initiated. The pilot must initiate a missed approach when he or she determines that: (a) The flight visibility is no longer sufficient to identify the visual references listed in 91.175(l)(4) which state the lights or markings of the threshold or the TDZ must be distinctly visible and identifiable to the pilot without reliance on the enhanced flight vision system; or Par 6 Page 7
AC 90-EFVS DRAFT DATE (b) The aircraft is not in a position to execute a safe landing. For an operation conducted under part 121 or part 135, an appropriate missed approach procedure would have to be immediately executed if the pilot were unable to control the descent rate of the aircraft to allow touchdown to occur within the TDZ of the intended landing runway. Page 8 Par 6
c. Visual References Required When Using EFVS. The minimum visual references specified in 91.175(l)(3) for operation below the authorized MDA or DH are the approach light system (if installed) or at least one out of several visual references that identify the runway threshold and the TDZ respectively. (1) The visual references that must be used to identify the runway threshold are: (a) The beginning of the runway landing surface. (b) The threshold lights. (c) The runway end identifier lights. (2) The visual references that must be used to identify the TDZ: (a) The runway TDZ landing surface. (b) The TDZ lights. (c) The TDZ markings. (d) The runway lights. (3) These visual reference requirements comprise a more stringent standard than the visual reference requirements prescribed under 91.175(c)(3) when using natural vision. The more stringent standard is needed because these EFVS devices might not display the color of the lights used to identify specific portions of the runway or might not be able to consistently display the runway markings. d. Stabilized Approaches. The FAA supports the worldwide safety initiative to implement a stabilized approach as standard operating procedure for all approaches involving all categories of airplanes. (See AC 120-71A, Appendix 2, Stabilized Approach: Concepts and Terms.) e. Precision Approaches. The pilot tracks the localizer and glideslope until visual acquisition of the runway environment is attained using natural vision and/or EFVS imagery, as necessary. Although EFVS can provide lateral and vertical guidance below DH, the available precision approach aid guidance display should be used and the EFVS crosschecked to aid in the landing transition. The typical EFVS flightpath for precision approaches is shown in Figure 1 below. FIGURE 1. EFVS FLIGHT PATH TECHNIQUES PRECISION APPROACH
AC 90-EFVS DRAFT DATE f. Nonprecision Approaches Using Vertical Guidance. The preferred method for conducting nonprecision approaches is to fly the aircraft on the descent angle shown on the approach plate using VNAV with deviation indications and guidance displayed on the HUD. The descent angle shown on the approach plate depicts a computed vertical path from the final approach fix (FAF) and altitude to the runway threshold at the published threshold crossing height (TCH). An example of this computed path is included in Figure 2. By using VNAV to track this path, the pilot maintains a stabilized approach and assures that the aircraft remains clear of terrain and obstacles until visual acquisition and landing. FIGURE 2. EFVS FLIGHT PATH TECHNIQUES APPROACH WITH VERTICAL PATH Page 10 Par 6
DATE DRAFT AC 90-EFVS Par 6 Page 11
g. Nonprecision Approaches, no VNAV. To prevent controlled flight into terrain (CFIT), the FAA recommends a stabilized descent for nonprecision approaches for transport category airplanes. A constant rate of descent method is preferred using VNAV, if available, or a selfcomputed descent rate if VNAV is unavailable. (1) A constant-angle, constant-rate descent profile is the safest profile in all but special cases. On approaches for which no vertical guidance is available to the pilot, the flightcrew should plan, execute, and monitor the approach with special care, considering wind conditions when choosing a target descent rate after the FAF. For two pilot aircraft, to assure vertical clearance from terrain and obstacles and to promote situation awareness, the pilot monitoring (PM) the approach (the pilot-not-flying) should announce crossing altitudes as published fixes and other points selected by the flightcrew are passed. The pilot flying (PF) should promptly adjust descent rate as appropriate. (2) For nonprecision approaches with no vertical guidance, the FPA reference cue, and FPV may be used to position the aircraft on an appropriate glidepath to the TDZ. An example of the FPV and FPA reference cue is shown in Figure 4. An example of the vertical path changes required for nonprecision approaches with no vertical guidance is shown in Figure 3. For these approaches, EFVS is used as follows: FIGURE 3. EFVS FLIGHT PATH TECHNIQUES NONPRECISION APPROACHES WITH NO VERTICAL PATH (a) When visual acquisition is attained by natural vision, the pilot should continue landing using normal techniques.
DATE DRAFT AC 90-EFVS (b) When visual acquisition is attained by EFVS alone, the pilot may continue the approach below MDA to 100 feet above the TDZ elevation and should use the following techniques: 1. Preset the FPA reference cue to an angle consistent with the published instrument approach procedure, the visual approach slope indicator/precision approach path indicator (VASI/PAPI) angle, or at least three degrees. 2. Continue at the MDA until the FPA reference angle cue is positioned over the desired touchdown point in the touchdown zone of the EFVS runway image. 3. Adjust the descent rate of the aircraft until both the FPA reference cue is positioned over the desired touchdown point and the FPV is positioned over the FPA reference cue. FIGURE 4. FLIGHT PATH ANGLE REFERENCE ANGLE CUE h. Obstacle Clearance. Par 6 Page 13
AC 90-EFVS DRAFT DATE (1) Flight visibility determined by natural vision continues to be an important element of any IAP. The new EFVS rule requires the enhanced flight visibility to be equal to or greater than the prescribed visibility minima for the IAP for the pilot to continue the approach below the MDA or DH. The pilot must then determine at 100 feet above the TDZ elevation and below that altitude whether there is sufficient flight visibility to continue the approach to a landing. The regulation requires that at this altitude and below, the flight visibility must be sufficient for the lights or markings of the threshold; or the lights or markings of the TDZ to be distinctly visible and identifiable to the pilot without reliance on the EFVS to continue to a landing. Page 14 Par 6
(2) Approaches with vertical guidance provide the highest level of safety for both obstacle clearance and controlled rate of descent. If vertical guidance is not provided by the navigation systems, the use of the HUD s FPV and FPA reference cue set to at least three degrees positioned over the TDZ will provide a visual descent point and vertical flight path guidance from the MDA, and assure that the aircraft will remain clear of obstacles, provided the aircraft does not deviate from the charted lateral course and the HUD s computed vertical path to the touchdown point located in the runway TDZ. (3) The same risks that exist today regarding a missed approach beyond the charted missed approach point will exist when using an EFVS. A pilot should always be aware of how far to proceed and how to position the aircraft on a segment of the missed approach procedure. (4) A missed approach below the decision altitude (DA), DH, or beyond the missed approach point (MAP) involves additional risk until established on the published missed approach procedure course and altitude since the obstacle clearance surfaces are based on the missed approach starting at these altitudes or point. (5) The pilot must also be aware that a published visibility may be increased above standard criteria due to a penetration of the 20:1 or 34:1 surfaces in the final approach and the obstacle clearance surfaces in the missed approach. When there are penetrations of these surfaces, the pilot must take precautions to avoid these obstacles when operating in the visual segment. 8. GUIDANCE ON EFVS OPERATIONAL REQUIREMENTS. a. Specific guidance for the airworthiness certification of the imaging system and HUD used in the EFVS are in Appendices 3 and 4 of this AC. b. As a minimum, the EFVS, as stated in 91.175(m), must have the following characteristics: (1) The display must be suitable for maneuvering the aircraft. (2) The EFVS must have either an FAA type design approval, or, for a foreign-registered aircraft, the EFVS must comply with all of the EFVS requirements of 91.175(l) and (m). (3) The EFVS must 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, such as a Forward Looking Infrared (FLIR), millimeter wave radiometry, millimeter wave radar, and low-light level image intensifying sensors.
AC 90-EFVS DRAFT DATE (4) The following EFVS sensor imagery and aircraft flight symbology must be presented on a HUD, or an equivalent display, so that they are clearly visible to the pilot flying in his or her normal position and line of vision, and looking forward along the flight path: (a) Airspeed. (b) Vertical speed. (c) Aircraft attitude. (d) Heading. (e) Altitude. (f) Command guidance as appropriate for the approach to be flown. (g) Path deviation indications. (h) FPV. (i) FPA reference cue. 9. PILOT KNOWLEDGE. a. Pilots should be knowledgeable of the guidance in this AC and of the 91.175 requirements for an EFVS system to be used in the conduct of IAPs. b. Pilots operating an EFVS should be able to demonstrate knowledge and proficiency in the use of this equipment through training and testing as required by the type of operation. As a minimum, pilots should be knowledgeable and proficient in the following areas to integrate EFVS use into instrument approach operations in all weather conditions. (1) The specific sensor technology to include limitations that impact enhanced vision in various environmental conditions, as well as sensor performance for viewing the runway environment and obstacles in the visual segment of the instrument approach procedure. The pilot should be aware of the limitation where the performance can be variable and unpredictable. (2) The use of HUD symbology, as well as the crew procedures to use this equipment to fly instrument approach procedures. Page 16 Par 7
(3) Runway and approach lighting systems. (4) EFVS operational considerations: (a) Warm-up requirements. (b) System alignment with HUD. (c) Adjustment of brightness and contrast of display. (d) Contrast differences between daytime and nighttime approach conditions. (5) EFVS HUD abnormal and systems limitations: (a) Visual anomalies such as noise, blooming, and thermal cross-over. (b) EFVS sensor capability in varying weather conditions. (6) Importance of cross-checking the HUD instrumentation presentations against the EFVS visual scene presentation to enable the pilot to recognize loss of situation awareness caused by malfunctions of the navigation equipment or improper presentation of elements in the visual scene during the approach. (7) Visual references as required in 91.175(l)(3). (8) Crew briefings and callouts, as applicable. (9) Duties of the PF and the PM, as applicable. (10) The effect of various approach types using an EFVS on: (a) Alignment at DH or MDA. (b) Precision approach. (c) Approaches with vertical guidance, nonprecision and visual. (11) Transition from EFVS imagery to natural vision. (12) Use of a published or operator-approved visual descent point (VDP) for descent below MDA. (13) Potential for close-in obstacles on nonprecision approaches with no published VDP. (14) Use and limitations of supplementary vertical information for situation awareness below DH or MDA.
AC 90-EFVS DRAFT DATE 10. PILOT GROUND AND FLIGHT/SIMULATOR TRAINING. For Parts 141, 142 and other training programs, EFVS training should follow the guidance provided in this AC. Additional guidance is provided by the FAA National Simulator Program. a. Overall Training Objectives. (1) Pilot training is comprised of both ground and flight segments designed to meet the pilot knowledge recommendations of this AC. Flight/simulator training is designed to improve pilot knowledge and proficiency using EFVS and HUD in instrument and visual approach operations. Knowledge and proficiency are key components of the successful implementation of an IAP using an EFVS during reduced visibility conditions. (2) For aircraft operated under part 91, the applicable pilot training requirements are specified in the Airline Transport Pilot and Aircraft Type Rating Practical Test Standards for Airplane and Airline Transport Pilot and Aircraft Type Rating Practical Test Standards for Helicopter. (3) Pilots obtaining or holding certificates and ratings under the provisions 14 CFR part 61 are subject to testing and proficiency checks under 61.58 and may need to obtain training in order to pass the check on all of the installed equipment on an aircraft. An examiner has the discretion to check a pilot on any installed equipment on an aircraft. Therefore, pilots should obtain training on all installed equipment, including an EFVS, to be able to demonstrate proficiency. Documentation of training can be accomplished through a part 141/142 training program or pilot logbook entry. (4) All pilots who conduct operations under part 91 must meet the currency requirements of 61.56, which include a review of those maneuvers and procedures that, at the discretion of the person giving the review, are necessary for the pilot to demonstrate the safe exercise of the privileges of the pilot certificate. b. Minimum Recommended Training. The FAA recommends each pilot in command of an aircraft equipped with an EFVS receive four hours of initial ground school training followed by a minimum of two hours of simulator training, in a simulator equipped with an EFVS or an EFVS-equipped aircraft. c. Additional Training. The additional flight and ground training requirements of parts 121, 125, and 135 are addressed in each of those respective parts and are mandated in the operator s OpSpecs. Once certified, the operators are required to comply with the provisions of the OpSpecs and all approved or accepted training and/or checking programs. The operator is responsible for the training and checking of each pilot using the EFVS, if authorized, in accordance with OpSpecs issued to the certificate holder under the pertinent and applicable parts of 14 CFR. Page 18 Par 9
DATE DRAFT AC 90-EFVS d. Pilot Monitoring Training. For a two-pilot aircraft, the PM should receive a sufficient amount of ground training to have a good understanding of the EFVS, its operation, and limitations. He or she should also receive simulator and/or aircraft training to achieve proficiency on the callouts and the Collision Risk Modeling (CRM) items associated with the use of the EFVS and repeater, if installed. e. Flightcrew Ground Training. The FAA recommends ground instruction in the following areas: (1) Controls, modes, and adjustments of EFVS HUD. (2) Importance of the design eye position in acquiring the proper EFVS image. (3) Transition from EFVS imagery to non-efvs natural vision and recognition of the required visual references. Par 8 Page 19
(4) Crew briefings and callouts. (5) Precision and nonprecision instrument approaches in both day and night conditions. (6) Descent procedures below the DH/MDA using the EFVS and HUD. (7) Rejected landing: loss of visual cues of the landing area, TDZ, or rollout area. (8) Use of caged and uncaged modes imaging sensor (if applicable) in crosswind conditions. (9) Weather associated with low ceilings and visibility. (10) Theory of system and component operation. (11) Obstacle clearance requirements: terminal instrument procedures (TERPS), vertical path (VPATH), VASI/PAPI, VDPs, etc. (12) Systems limitations, normal, abnormal, and emergency procedures. (13) Runway incursion detection. f. Flightcrew Flight or Simulator Training. The FAA recommends that EFVS flight training be accomplished in a simulator or an aircraft. The simulator should be either a level C simulator with a daylight visual display or a level D simulator. In order to be effective, the simulator should be qualified by the FAA s National Simulator Program for EFVS training and testing. The simulator EFVS visibility should be adjustable and set to realistic values when training in the areas listed below. The flightcrew or simulator training program should include instruction on at least the events listed below. Two of the events should be daytime approaches. (1) (Simulator) Several snapshots of different weather conditions on the ground. (2) With the simulator frozen at 200 feet and 100 feet AGL. (3) One takeoff and visual approach. (4) ILS where the PF sees the required visual references using the EFVS at approximately 500 feet AGL, and the PM sees the required visual references without the EFVS at DH. (5) One ILS where the PF sees the required visual references using the EFVS at approximately 250 feet AGL, and the PM sees the required visual references without the EFVS at approximately 120 feet AGL.
DATE DRAFT AC 90-EFVS (6) One ILS where the PF sees the required visual references using the EFVS at approximately 250 feet AGL, and the PM does not see the required visual references without the EFVS at 100 feet AGL. (7) One nonprecision approach with vertical guidance where the PF sees the required visual references using the EFVS at approximately 50 feet above the MDA, and the PM sees the required visual references without the EFVS at approximately 120 feet AGL. (8) One straight-in nonprecision approach, offset by approximately 20 degrees. (9) Reserved for low visibility takeoffs following a proof of concept to be developed. 11. EFVS OPERATIONAL APPROVAL PROCESS. This process addresses: U.S. air carriers and operators, Foreign persons or foreign air carriers operating U.S.-registered aircraft within or outside the United States, and Foreign air carriers operating foreign--registered aircraft within the United States. a. For Part 91 Operators and U.S. Air Carriers. The general process used to obtain operational approval of an EFVS under 91.175(l) and (m) is shown in Figure 5. (1) For Part 91 Operators. While no specific operational approval is required, operators and pilots should accomplish and document any training. Part 91 training may be documented at a part 141/142 facility or a pilot logbook entry made by the certificated flight instructor accomplishing the training. (2) U.S. Air Carriers. Par 9 Page 21
(a) Applicants should submit documentation requesting operational approval of an EFVS to the FAA certificate-holding district office (CHDO) or Flight Standards District Office (FSDO) responsible for that operator s certificate. (b) Operational documentation should be evaluated by the CHDO/FSDO and forwarded, with any recommendations, to the Flight Technologies and Procedures Division, AFS-400, and the Air Transportation Division, AFS-200, FAA Headquarters, Washington, D.C., for review and concurrence which is necessary prior to the CHDO/FSDO issuing OpSpecs authorizing use of the EFVS. (c) The major components of an EFVS application include: 1. Operating procedures, HUD, EFVS characteristics and limitations, airport lighting and markings. 2. Crew training: PF/PM procedures, crew callouts, missed approach techniques, and crew duties. 3. Simulator: initial and recurrent training. 4. Maintenance: training, continued airworthiness program. 5. Airplane and equipment: visual cues, cockpit cutoff angle, Aircraft Flight Manual (AFM). 6. Minimum Equipment List (MEL): proposed changes. 7. OpSpecs: proposed changes.
DATE DRAFT AC 90-EFVS FIGURE 5. EFVS OPERATOR APPROVAL PROCESS FOR U.S. AIR CARRIERS AND OPERATORS b. For Foreign Persons or Foreign Air Carriers Operating U. S.-Registered Aircraft. The general process used to obtain operational approval of an EFVS under 91.175(l) and (m) is shown in Figure 6. Additional criteria is: (1) Acceptable criteria includes the latest version of this AC or other equivalent Joint Aviation Authorities (JAA) (European), European Aviation Safety Agency (EASA), or International Civil Aviation Organization (ICAO) criteria (when developed) that are acceptable to the FAA.Previous authorizations by the FAA, in accordance with earlier criteria, may continue to apply that earlier criteria. When seeking additional operational credit, each operator must follow the criteria addressed in the current version of this AC (e.g., EFVS HUD operations), or equivalent criteria acceptable to the FAA. (2) Aircraft Flight Manual (AFM) Provisions. U.S.-registered aircraft used by foreign persons or foreign air carriers for EFVS operations must have FAA type design approval. AFM provisions should reflect an appropriate level of EFVS capability that meets the features and characteristics of 91.175(m) and the requirements as outlined in this AC, or other acceptable criteria approved by the FAA. (3) Maintenance Program Approval. In accordance with 129.14, each foreign air carrier and each foreign person operating a U.S.-registered aircraft within or outside the Par 10 Page 23
AC 90-EFVS DRAFT DATE United States in common carriage, shall ensure that each aircraft is maintained in accordance with a program approved by the Administrator. This maintenance program should also address issues unique to EFVS as discussed in paragraph 9 of this AC. (4) MEL Approval. 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 EFVS system and components should be taken into consideration during MEL submission, review, and approval. Page 24 Par 10
(5) Common Carriage. Foreign air carriers conducting EFVS operations within the United States, or a foreign person or foreign air carrier operating a U.S.-registered aircraft solely outside the United States in common carriage may be authorized for EFVS operations in accordance with the provisions of their own regulatory provisions and the standard provisions of part 129. (6) Not Common Carriage. No specific FAA authorization is required for foreign persons conducting EFVS operations with U.S.-registered aircraft when common carriage in not involved. They must, however, meet the regulatory provisions of the State in which they operate for EFVS operations and comply with 91.175(l) and (m). (7) Issuance of Part 129 OpSpecs. Foreign air carriers operating to U.S. airports that meet applicable provisions above may be authorized EFVS operations through issuance of appropriate part 129 OpSpecs. Before issuing such OpSpecs to a foreign air carrier, principal inspectors (PI) will ensure: (a) EFVS equipment is installed in accordance with an FAA-approved type certificate (TC) or STC for the make/model/series of aircraft. (b) The aircraft approved AFM contains EFVS provisions appropriate to the EFVS operation authorized. (c) The State of the Operator CAA has authorized/approved EFVS operations for the carrier in accordance with the provisions of this AC or other FAA-accepted criteria. (d) The FAA has approved the maintenance program and MEL for the aircraft, including EFVS provisions. (e) The carrier has an EFVS training program for flight crewmembers approved/ authorized by the State of the Operator CAA. NOTE: Although EFVS training is highly recommended, this is solely the responsibility of the State of the Operator CAA, for operations conducted solely outside the United States.
AC 90-EFVS DRAFT DATE FIGURE 6. EFVS APPROVAL PROCESS FOREIGN PERSONS OR FOREIGN AIR CARRIERS OPERATING U.S. REGISTERED AIRCRAFT c. For Foreign Air Carriers Operating Foreign-Registered Aircraft within the United States. The general process used to obtain operational approval of an EFVS under 91.175(l) and (m) is shown in Figure 7. Additional guidance is provided below: (1) AFM Provisions. 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 91.175. (2) Common Carriage. Foreign air carriers conducting EFVS operations within the United States, in common carriage may be authorized for EFVS operations in accordance with the provisions of their own regulatory provisions and the standard provisions of part 129. FIGURE 7. EFVS APPROVAL PROCESSES FOREIGN AIR CARRIERS OPERATING FOREIGN REGISTERED AIRCRAFT WITHIN THE UNITED STATES Page 26 Par 10
DATE DRAFT AC 90-EFVS (3) Issuance of Part 129 OpSpecs. Foreign air carriers operating to U.S. airports that meet applicable provisions above may be authorized EFVS operations through issuance of appropriate part 129 OpSpecs. Before issuing such OpSpecs to a foreign air carrier, PIs shall ensure: (a) EFVS equipment is installed in accordance with an approved TC or STC for the make/model/series of aircraft. (b) The aircraft approved AFM contains EFVS provisions appropriate to the EFVS operation authorized. Par 10 Page 27
(c) The State of the Operator has authorized/approved EFVS operations. (d) The State of the Operator CAA has approved the maintenance program and MEL for the aircraft including EFVS provisions. (e) The carrier has an EFVS training program for flight crewmembers approved/ authorized by the State of the Operator CAA. 12. GUIDANCE ON EFVS MAINTENANCE REQUIREMENTS. a. If required by part 25, appendix H, H25.3 (b)(1), Instructions for Continued Airworthiness, Maintenance instructions, the EFVS must be maintained in accordance with the aircraft manufacturer s or the equipment manufacturer s maintenance instructions. This requirement includes cleanings, inspections, adjustments, tests, and lubrication. If not required by the applicable regulations, EFVS equipment maintenance must be accomplished on an as-required/on-condition basis. b. An operator of aircraft operated under part 91 may utilize an approved inspection program or the manufacturer s recommended maintenance program that contain the maintenance specifications for the EFVS. The following areas are identified by the FAA as essential elements of an adequate maintenance program: (1) Maintenance Organization/Facility. The operator s maintenance organization/ facility is responsible for seeing that maintenance on the EFVS is performed in accordance with its maintenance instructions. The organization/facility will also ensure that competent personnel, adequate facilities, and equipment training is provided for EFVS maintenance. (2) Maintenance Manuals and Documents. Each maintenance facility must maintain applicable maintenance manuals for the specific equipment being maintained. (3) Training and Qualification. Because of the complexity and safety-critical nature of EFVS maintenance, the operator should ensure that each person performing maintenance or inspections on EFVS is properly trained, qualified, and understands the maintenance instructions. Inspection personnel training and documentation of EFVS maintenance should be part of the training program. (4) Inspection Periods. Inspection periods are established by the aircraft manufacturer s or instrument manufacturer s maintenance instructions to determine that all components of the equipment are complete, serviceable, and may be expected to remain in this condition until the next inspection.
DATE DRAFT AC 90-EFVS James J. Ballough Director, Flight Standards Service Par 11 Page 29 (and 22)
AC 90-EFVS DRAFT DATE Appendix 1 APPENDIX 1. ACRONYMS AND ABBREVIATIONS AC ACO AEG AFM AGL ASR AWO BA BASA IPA CAA CHDO CRM DH EASA EFV EFVS EVS FMS FPA Advisory Circular Aircraft Certification Office Aircraft Evaluation Group Aircraft Flight Manual Above Ground Level Airport Surveillance Radar All-Weather Operations Bilateral Agreement Bilateral Aviation Safety Agreement with Implementation Procedures Civil Aviation Authority Certificate-Holding District Office Collision Risk Modeling Decision Height European Aviation Safety Agency Enhanced Flight Visibility Enhanced Flight Vision System Enhanced Vision System Flight Management System Flight Path Angle Page 1
DATE DRAFT AC 90-EFVS Appendix 1 FPV Flight Path Vector FSB GPS GPWS HAT HDD HUD ICA ICAO IFR ILS JAA Flight Standardization Board Global Positioning System Ground Proximity Warning System Height Above Touchdown Head-Down Display Heads-Up Display Instructions for Continued Airworthiness International Civil Aviation Organization Instrument Flight Rules Instrument Landing System Joint Aviation Authorities (European) LNAV/VNAV Lateral Navigation/Vertical Navigation LOC MDA MLS MEL MMEL NDB PAI PF PM PMI POI Localizer Minimum Descent Altitude Microwave Landing System Minimum Equipment List Master Minimum Equipment List Nondirectional Radio Beacon Principal Avionics Inspector Pilot Flying Pilot Monitoring Principal Maintenance Inspector Principal Operations Inspector Page 2
AC 90-EFVS DRAFT DATE Appendix 1 RNAV Area Navigation SAE STC SVS TC TCAS Society of Automotive Engineers Supplemental Type Certificate Synthetic Vision System Type Certification Traffic Alert And Collision Avoidance System Page 3
DATE DRAFT AC 90-EFVS Appendix 1 TCH Threshold Crossing Height TDZ TERPS TSO VOR VDP Touchdown Zone U.S. Standard for Terminal Instrument Procedures Technical Standard Order Very High Frequency Omnidirectional Range Visual Descent Point Page 3 (and 4)
DATE DRAFT AC 90-EFVS Appendix 1 Page 1
DATE DRAFT AC 90-EFVS Appendix 3 APPENDIX 2. DEFINITIONS For the purpose of operations under this advisory circular (AC), the following definitions are provided: c. 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, or propellers. The office offers certification expertise on investigating and reporting aircraft accidents, incidents, and service difficulties. The term ACO refers to the Engine Certification Office (ECO), the Rotorcraft Certification Office (RCO), the Special Certification Office (SCO), the Aircraft Certification Office (ACO), and all other ACOs. d. 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 directorate and/or the manufacturers. AEGs may be co-located with an accountable directorate or one of its elements. e. Approaches Using Vertical Guidance. An approach with vertical navigation (VNAV) guidance other than that provided by a precision approach. f. Certificate-Holding District Office (CHDO). The Federal Aviation Administration (FAA) Flight Standards District Office (FSDO), certificate management office (CMO), or Certificate Management Unit (CMU) assigned by the FAA to have operating certificate oversight responsibility for a particular operator. g. Enhanced Flight Vision System (EFVS). 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, such as a Forward Looking Infrared (FLIR), millimeter wave radiometry, millimeter wave radar, low light level image intensifying h. Enhanced Flight Visibility. The average forward horizontal distance from the cockpit of an aircraft in flight at which prominent topographical objects may be clearly distinguished and identified by day or night by a pilot using an EFVS. i. 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, FLIR). Unlike an EFVS, an EVS does not necessarily provide the additional flight information/ symbology required by part 91, 91.175(m), may not use a heads-up display (HUD), and may not be able to present the image and flight symbology in the same scale and alignment as the outside view. This system can provide situation awareness to the pilot, but does not meet the regulatory requirements of 91.175(m). As such, an EVS cannot be used as a Page 1 (and 4)
AC 90-EFVS DRAFT AC 90-EFVS Appendix 3 means to determine enhanced flight visibility and descend below the minimum descent altitude (MDA) or decision height (DH). j. Flight Standardization Board (FSB). A designated group of operations inspectors who determine type rating, certification, and training requirements for new or modified aircraft. k. Heads-Up Display (HUD) Including Head-Up Guidance System. An airplane system that provides heads-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. l. Head-Down Display (HDD). A display or suite of displays that provide control, performance, and navigational information that is presented to the pilot on conventional head-down instrumentation, or integrated electronic flight displays. m. 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). n. Nonprecision Approach. A standard instrument approach procedure in which no electronic glideslope is provided. o. Pilot Monitoring (Previously Known As Pilot-Not-Flying). (1) Operators establish appropriate monitoring procedures for each type of low visibility approach, landing, and missed approach. Procedures should ensure that adequate crew attention can be devoted to control of aircraft flight path, displacements from intended path, mode annunciations, failure annunciations and warnings, and adherence to minima requirements associated with DA(H) or MDA(H). (2) In the event that a monitored approach is used, (e.g., where the first officer is responsible for control of the aircraft flight path by monitoring of the automatic flight system) appropriate procedures should be established for transfer of control to the pilot who will be making the decision for continuation of the landing at or prior to DA(H) or MDA(H). (3) Monitoring procedures should not require a transfer of responsibility or transfer of control at a time that could interfere with safe landing of the aircraft. Procedures for calling out failure conditions should be pre-established, and responsibility for alerting other flight crewmembers to a failure condition should be clearly identified. Page 2