AC 20-167B
6.2.5.6 Touchdowns with a bank angle that is not hazardous to the aircraft.
Demonstrated performance of the installed EFVS at representative visibilities for EFVS approach system and EFVS landing system operations as described in this AC will determine any additional limitation (for example, crosswind and offset).
6.2.5.7 A normal de-rotation.
6.2.5.8 Satisfactory and smooth control of the path of the aircraft along the runway centerline through rollout to a safe taxi speed.
6.2.5.9 A safe go-around anytime including up to touchdown in all aircraft approach/landing configurations to be certified.
6-4
AC 20-167B Appendix A APPENDIX A. FAA EFVS 14 CFR COMPLIANCE (PARTIAL LIST) A.1 Airworthiness Standards.
• Certification Procedures for Products and Articles (14 CFR part 21).
• Normal Category Airplanes (14 CFR part 23).
• Transport Category Airplanes (14 CFR part 25).
• Normal Category Rotorcraft (14 CFR part 27).
• Transport Category Rotorcraft (14 CFR part 29).
A.2 EFVS Compliance.
The following requirements address EFVS compliance. These requirements may also be in addition to those requirements applicable to a HUD and the basic avionics installation. The amount of new test data can be determined by the individual application, availability, and relevance of data.
Table A-1. EFVS Acceptable Methods of Compliance 14 CFR Description Acceptable Method of Compliance
23.2135, 25.143, 27.143,
29.143 General controllability and maneuverability Analysis, Simulation, Flight Test
23.2160, 25.251, 27.251,
29.251 Vibration and buffeting Flight Test
23.2210, 23.2230, 25.301,
27.301, 29.301 Loads Analysis
23.2230, 25.303, 27.303,
29.303 Factor of safety Analysis
23.2235, 25.307, 27.307,
29.307 Proof of structure Analysis A-1
AC 20-167B Appendix A 14 CFR Description Acceptable Method of Compliance
25.561m 25.562(c)(5) Emergency landing conditions; Head Injury Criterion (HIC) Analysis
23.2240, 25.571, 27.571,
29.571 Damage-tolerance and fatigue evaluation of structure Analysis
25.571(e) Damage-tolerance and fatigue evaluation of structure(discrete source) evaluation Analysis and/or Test (See Note)
23.2515, 25.581, 27.610,
29.610 Lightning protection Analysis
23.2250, 25.601, 27.601,
29.601 General Design and Construction Drawing
23.2250, 23.2260, 25.603,
27.603, 29.603 Materials Drawing
23.2260, 25.605, 27.605,
29.605 Fabrication methods Drawing
23.2255, 25.609, 27.609,
29.609 Protection of structure Drawing
23.2255, 25.611, 27.611,
29.611 Accessibility provisions Drawing
23.2260, 25.613, 27.613,
29.613 Material Strength properties and material design values Drawing, Analysis, Test (See Note)
23.2265, 25.619, 27.619,
29.619 Special factors Analysis
23.2265, 25.625, 27.625,
29.625 Fitting Factors Analysis
23.2245, 25.629(d)(8) Aeroelastic stability Analysis, Test A-2
AC 20-167B Appendix A 14 CFR Description Acceptable Method of Compliance
23.2320(d), 25.631,
29.631 Bird strike damage Analysis, or Test if necessary. (Testing should be accomplished unless the analysis shows that the integrity of the original structure has not been compromised by EFVS installation modification.)
23.2600, 25.771, 27.771,
29.771 Pilot compartment Flight Test
23.2600(a), 25.773,
27.773, 29.773 Pilot compartment view Flight Test
23.2600, 23.2610, 25.777,
27.777, 29.777 Flight deck controls Flight Test
23.2500, 23.2505,
25.1301, 27.1301, 29.1301 Function and installation Ground Test and Flight Test
25.1302 Installed systems and equipment for use by the flightcrew Analysis, Simulation, Flight Test
23.2500, 23.2505,
25.1309, 27.1309, 29.1309 Equipment, systems, and installations Analysis and/or Test and Design data
25.1316, 27.1316, 29.1316 System lightning protection Analysis and Ground Test
23.2520, 25.1317,
27.1317, 29.1317 High-intensity Radiated Fields (HIRF) Protection Ground Test and Flight Test Analysis/Data
23.2500, 23.2610,
25.1321, 27.1321, 29.1321 Arrangement and visibility Ground Test and Flight Test
23.2605, 25.1322,
27.1322, 29.1322 Warning, caution, advisory lights Ground Test and Flight Test
25.1323, 27.1323, 29.1323 Airspeed indicating systems Flight Test A-3
AC 20-167B Appendix A 14 CFR Description Acceptable Method of Compliance
23.2500 23.2505, 23.2510,
23.2600, 23.2605,
27.1335, 29.1335 Flight director systems Ground Test and Flight Test
23.2525, 23.2500,
23.2525, 23.2605,
25.1351, 27.1351, 29.1351 Electrical Systems and Equipment;
General Analysis
25.1353, 29.1353 Electrical equipment and installation Analysis
23.2500, 23.2505,
23.2510, 23.2525,
25.1357, 27.1357, 29.1357 Circuit protective devices Analysis and Ground Test
23.2500, 23.2600,
25.1381, 27.1381, 29.1381 Instrument lights Ground Test and Flight Test
23.2165(a)(1), 23.2540(a),
23.2600(a), 25.1419,
27.1419, 29.1419 Ice protection Analysis
23.2510, 25.1431, 29.1431 Electronic equipment Analysis and Ground Test
23.1549(e), 25.1459(e),
27.1459(e), 29.1459(e) Flight data recorders Flight test
23.2610, 25.1501,
27.1501, 29.1501 Operating Limitations and Information;
General Flight Test
23.2610, 25.1523,
27.1523, 29.1523 Minimum flightcrew Flight Test or Simulation
23.2610, 25.1525,
27.1525, 29.1525 Kinds of operation Flight Test
23.1529, 25.1529,
27.1529, 29.1529 Instructions for Continued Airworthiness Design Data A-4
AC 20-167B Appendix A 14 CFR Description Acceptable Method of Compliance
23.2620, 25.1581,
27.1581, 29.1581 Aircraft flight manual; General Design Data and Flight Test
23.2620, 25.1583,
27.1583, 29.1583 Operating limitations Flight Test Data
23.2620, 25.1585,
27.1585, 29.1585 Operating procedures Flight Test Data
26.47 Holders of and applicants for a supplemental type certificate - alterations and repairs to alterations.
Analysis A-5
AC 20-167B Appendix B APPENDIX B. SA MPLE EFVS FLIGHT TEST CONSIDERATIONS B.1 General Flight Test Considerations.
The objectives of the flight test program are to demonstrate the installed EFVS performs its intended function when installed, and to document that the installed EFVS is eligible for operational approval.
B.1.1 Testing should include all phases of flight, approach types, approach course geometries, and aircraft configurations for which the applicant seeks to operate the EFVS. The EFVS minimum performance standards require the assessment of the EFVS display when used in conjunction with the head up flight indications required in § 91.176 and listed in paragraph 4.4.1.3 of this AC. For effective post-flight analysis and evaluation of the results, past experience has shown that recorded time-stamped video of exactly what is displayed on the HUD is recommended.
B.1.2 In general, the test program should demonstrate that the EFVS image, with superimposed flight symbology, does not mislead, distract or jeopardize the safety of the approach, landing and rollout. Without requiring exceptional pilot skill, alerting, strength, or workload, the image/symbology should allow and provide the visual cues for the pilot to perform the EFVS approach or EFVS landing as described in § 91.176.
Minimum performance standards require the assessment of the HUD/EFVS approach system display when used in conjunction with the flight instrumentation required in § 91.176 and listed in paragraph 4.4.1.3 of this AC.
B.1.3 The flight test should demonstrate that the EFVS display of imagery and HUD symbology are readable and usable without mutual interference. Flight testing should demonstrate the brightness and contrast levels of the imagery and the symbology can be effectively controlled and provide satisfactory contrast between the two. Since flightdeck and external light levels can affect the readability of the EFVS display and can change significantly throughout the approach and landing operation, flight testing should demonstrate that control of display brightness and contrast in dynamic conditions does not require excessive workload for the pilot. Additionally, flight tests should demonstrate that controls can clear the EFVS imagery from the HUD in the event that the visual field becomes unusable due to system malfunction or external environmental conditions.
B.1.4 Environmental conditions should be chosen to exercise both automatic and manual control of items such as brightness, contrast, and gain, and any other parameters affecting the image displayed to the pilot.
B.1.5 An applicant may reuse previously collected certification flight test data to meet the criteria specified in this AC if the applicant can show the previously collected certification data is relevant to the current certification project. The FAA and the applicant will agree on the reuse of any previously collected certification flight test data.
For example, if an applicant is certifying a previously certified EFVS approach system as an EFVS landing system, and the applicant can show test data collected to certify the B-1
AC 20-167B Appendix B EFVS approach system meets the criteria specified in this AC, the applicant may only need to conduct the additional EFVS landing system specific test points listed in this appendix.
Figure B- 1. Depiction of Visual Advantage B.2 Evaluation of Visual Advantage.
In addition to demonstrating system safety, the flight test program should demonstrate that the installed EFVS is capable of successfully completing the relevant § 91.176(a) or 91.176(b) operation in a representative sampling of weather and environmental conditions with flight visibilities lower than the published instrument approach visibility minimums as described in section B.3 of this AC.
B.2.1 A successful demonstration of visual advantage in accordance with appendix B is sufficient to support certification of the installed EFVS. However, while not required for certification of the EFVS, quantification of the demonstrated EFVS visual advantage is required for some EFVS operational approvals.
B.2.2 The demonstration of a quantified visual advantage is necessary to authorize the provisions in OpSpec/MSpec/Letter of Authorization (LOA) C048 which allow 14 CFR part 121, 125, and 135 certificate holders to use EFVS-equipped aircraft to:
B.2.2.1 Release a flight under instrument flight rules (IFR) when the forecast weather is equal to or greater than the authorized minimums for use with an EFVS. (§§ 121.613, 125.361, and 135.219); and B-2
AC 20-167B Appendix B B.2.2.2 Continue an approach when the weather is reported to be equal to or greater than authorized minimums for use with an EFVS. (§§ 121.651,
125.325, 125.381, and 135.225.)
B.2.3 If the applicant intends the system to be used for EFVS operations that require OpSpec/MSpec/LOA C048, it is recommended that the applicant also demonstrate and document the EFVS’s quantified visual advantage during the certification testing of the EFVS. Further guidance on how to quantify the visual advantage of the EFVS is found in appendix C.
B.3 Minimum Flight Test Conditions Observed.
Testing should demonstrate fault-free approaches for EFVS approach systems or approach and landings for EFVS landing systems in as many of the conditions listed below as practicable and as applicable to the system’s intended function. Additionally, a sufficient number of approaches will be needed in a representative sampling of weather and environmental conditions with flight visibilities lower than the published instrument approach visibility minimums to demonstrate that the EFVS can provide sufficient enhanced flight visibility to complete the EFVS operation. Past experience has shown that the applicants with a new EFVS should plan for no less than 50 fault-free approaches for EFVS approach systems or approach and landings for EFVS landing systems. Include go-around performance in testing. Typically, at least five satisfactory go-arounds are included in testing.
B.3.1 The applicant and the FAA will agree on the minimum number of successfully demonstrated test approaches.
B.3.2 Testing of the EFVS systems should be conducted in as many of the environmental conditions listed below as practical and applicable to the system’s intended function.
The environmental conditions should be chosen to exercise both the automatic and manual control of items such as brightness, contrast, gain, and any other parameter that affects the image displayed to the pilot. The actual environmental conditions used for the flight test program must be agreed to by the FAA. Address the conditions in the following subsection when developing the flight test program:
B.3.2.1 EFVS approach and EFVS landing systems should be tested under the following conditions:
• Night visual flight rules (VFR) conditions over various topography (urban, rural, snow covered, etc.);
• Day and night IFR conditions over various topography;
• Representative levels of rainfall;
• Representative levels of snowfall;
• Representative levels of fog;
• Haze;
B-3
AC 20-167B Appendix B
• Representative sun angles;
• Representative airport lighting configurations to include airports with LED lighting where relevant to the systems intended function;
• Representative airport/runway surface conditions (dry, wet, standing water, snow cover);
• Representative thermal crossover conditions as applicable for the EVS sensor;
• Representative crosswind and off-set approach course conditions regarding lateral FOR;
• Representative runway surface types (dirt, asphalt, concrete, etc.);
• Representative adjacent surfaces types (dirt, asphalt, concrete, etc.);
and
• Representative instrument approaches for the intended EFVS operations.
B.3.2.2 Additional conditions for EFVS landing systems.
• Representative runway widths usable to aircraft on which the EFVS is being installed; and
• Representative runway slopes (within the aircraft limitations).
B.3.3 Data Collection.
The applicant should propose a method to collect and analyze system performance in order to demonstrate that the installed EFVS meets all relevant criteria. The data collection method found in RTCA DO-390/EUROCAE ED-291, Test Procedures for Quantitative Visual Advantage, is recommended for use on all EFVS flight tests in support of appendix B. Collecting data in a manner consistent with RTCA DO-390/ED- 291 could support future certification or operational approval applications and mitigate the need to fly additional test flights.
B.3.4 Faulted Approaches.
A faulted approach occurs anytime the pilot is unable to complete a safe and successful approach, landing, or rollout and turnoff. Examples of faulted approaches are included below. The list provides examples. Each unique system design could generate additional faulted approach cases.
B.3.4.1 Examples of a faulted approach:
• HUD or EFVS approach system failure has occurred;
• At 100 ft above TDZE, the indicated airspeed, heading, or attitude are not satisfactory for a normal flare and landing, due to a confusing or misaligned EFVS approach system image;
B-4
AC 20-167B Appendix B
• At 100 ft above TDZE, the aircraft is not positioned so that the flightdeck is within and tracking so as to remain within the lateral confines of the extended runway;
• Due to a confusing or misaligned image, the touchdown will be too short or too long; and/or
• The EFVS approach system image degrades the flyability of the display such that a successful approach to DA/DH or MDA is not possible.
B.3.4.2 A faulted approach does not occur due to a lack or loss of enhanced flight visibility due to the atmospheric conditions, so long as a successful missed approach or rejected landing is executed.
B.3.4.3 A faulted approach also does not occur due to a ir traffic control intervention, interference from other aircraft, interference from ground vehicles or persons, interference from animals (e.g. birds), or any other reason not directly related to the EFVS.
B.4 Taxi Evaluation Steps.
B.4.1 Assess EFVS/HUD combination while taxiing and making identification of objects on runways, taxiways, and parking aprons.
B.4.2 Verify that the EFVS display, with the image displayed, does not significantly alter the color perception of the external scene to an extent which jeopardizes the pilot’s ability to distinguish the relevant features of the environment, precluding the performance of any task.
B.4.3 Verify that the HUD combiner, with the image displayed, does not significantly alter the color perception of the external scene to an extent which jeopardizes the pilot’s ability to distinguish the relevant features of the environment, precluding the performance of any task.
B.4.4 Assess any burn-in or blooming (if applicable) on the EFVS image from high intensity heat sources such as operating engines, stationary lights etc.
B.5 Take off Evaluation Steps.
B.5.1 Ensure correct pitch angle is achieved using HUD pitch symbology.
B.5.2 Verify that the symbology in EFVS mode is clear, visible, and does not cause overcontrol or oscillations in acquiring and maintaining the required ground track.
B.5.3 Confirm that the HUD with EFVS provides the pilot with a quick-glance (instant) sense of flight parameters.
B-5
AC 20-167B Appendix B B.5.4 Assess the transition to different selected vertical modes.
B.5.5 Evaluate the EFVS image during the take-off roll and throughout the climb segment, against the attributes listed in the flight test evaluation matrix. See Table B-1 and Table B-2.
B.6 Climb and Descent and Lateral Modes Evaluation Steps.
B.6.1 Evaluate climb, descent, and lateral modes in day and night instrument meteorological conditions and visual meteorological conditions to assess HUD/EFVS compatibility.
B.6.2 During vertical and lateral guidance maneuvers, evaluate the EFVS image against the attributes listed in the flight test evaluation matrix. See Table B-1 and Table B-2.
B.7 Instrument Approaches.
B.7.1 During any instrument approach for which approval is sought, EFVS compatibility should be evaluated against the attributes listed in the flight test evaluation matrix. See Table B-1 and Table B-2.
B.7.2 Speed control should be demonstrated to be maintained within +10/-5 knots of the approach speed, whether manually controlled or with auto-throttle, as proposed by the applicant up to the point where the throttles are retarded for landing.
B.7.3 EFVS landing systems may fly final approach courses with offsets greater than 3 degrees. In this case, establish the maximum allowable final approach course offset by flight test. The flight test should address factors related to the offset, such as HUD/EFVS field of view, crosswinds, and the maximum drift angle for a conformal FPV. Section 91.176 permits EFVS to touchdown for approaches with offsets up to 15 degrees. The flight test evaluation should factor this offset into potential limitations and airworthiness approvals.
B.7.4 The EFVS must present all display requirements of § 91.176(a)(1) or § 91.176(b)(1) throughout the entire instrument approach. If any of the required EFVS display elements are not shown during an approach type that the aircraft is approved to conduct
(i.e., steep approaches), then a limitation should be annotated in the AFM.
B.8 Final Approach from the DA/DH or MDA, Flare Landing, and Rollout to a Safe Taxi Speed.
B.8.1 While using EFVS during final approach and through the flare (below 50 ft), touchdown roll or go-around, and turn-off, assess the performance of the EFVS image and displayed symbology against the attributes listed in the flight test evaluation matrix.
See Table B-1 and Table B-2.
B-6