AC 20-167A

Appendix B B-4 FHA NO.

FAILURE

CONDITION PHASE OF FLIGHT PILOT ACTION HAZARD

INDEX OBJECTIVE

1.5 Loss of HUD and EFVS Imagery Final Approach - From 100 ft. height above touchdown zone elevation to Landing

Pilot would continue the approach and land MINOR 10-3

2.0 MISLEADING

INFORMATION

2.1 Misleading EFVS imagery on HUD Taxi Enroute Terminal Arrival Final Approach - Above 100 ft height above touchdown zone elevation Go-Around Crew would revert to standard head down procedures MINOR 10-3

2.2 Misleading EFVS imagery on HUD Final Approach - From 100 ft. height above touchdown zone elevation to Landing Crew would perform a goaround or possibly a minimum flare landing MAJOR 10-5

2.3 Misleading HUD symbology Taxi and Takeoff Enroute Terminal Arrival Final Approach - Above 100 ft. height above touchdown zone elevation Final Approach - From 100 ft. height above touchdown zone elevation to Landing Go-Around Pilot would take appropriate action as defined in AFM for standard displays and HUD

Various failure conditions with the highest hazard index being MAJOR Various failure conditions with the highest objective being 10-5

2.4 Misleading EFVS imagery and HUD symbology Final Approach - Above 100 ft. height above touchdown zone elevation

Copilot would recognize condition using copilot's PFD MAJOR 10-5

Appendix B B-5 FHA NO.

FAILURE

CONDITION PHASE OF FLIGHT PILOT ACTION HAZARD

INDEX OBJECTIVE

2.5 Misleading EFVS imagery and HUD symbology Final Approach - From 100 ft. height above touchdown zone elevation to Landing Crew would perform a goaround or possibly a minimum flare landing MAJOR 10-5

3.0 OBSTRUCTION

OF PILOT'S VIEW

3.1 Obstruction of the pilot's view through the HUD Takeoff Pilot would abort takeoff prior to V1 MAJOR

10-5

3.2 Obstruction of the pilot's view through the HUD Taxi Enroute Terminal Arrival Pilot would take appropriate action MINOR 10-3

3.3 Obstruction of the pilot's view through the HUD Final Approach - Above 100 ft. height above touchdown zone elevation Go-Around Pilot would take appropriate action MAJOR

10-5

3.4 Obstruction of the pilot's view through the HUD Final Approach - From 100 ft. height above touchdown zone elevation to Landing Pilot would execute a goaround MAJOR

10-5

Appendix C C-1 APPENDIX C. EFVS SAFETY STANDARDS C.1 Safety factors for EFVS described in this AC Safety standards for the following factors include:

C.1.1 An acceptable degree of interference of the window or “window and HUD” view, potential image misalignment, distortion, and the potential for pilot confusion or misleading information.

C.1.2 Determination of EFVS imagery as flight guidance. The FAA does not intend for the EFVS imagery to be used either as a means of flight guidance/instrument guidance, or as the substitution for the outside view prior to DA/DH or MDA.

C.1.3 Criteria to determine EFVS is of the kind and design appropriate to the following functions:

C.1.3.1 Presenting an enhanced view that would aid the pilot during the approach.

C.1.3.2 Displaying an image that the pilot can use to detect and identify the “visual references for the intended runway” required by 14 CFR §

91.176(b)(3) to continue the approach with vertical guidance to 100 feet height above touchdown (HAT).

C.1.3.3 Depending on the atmospheric conditions and the particular visual references that happen to be distinctly visible and identifiable in the EFVS image, these two functions (found in paragraphs C.1.3.1 and C.1.3.2) would support its use by the pilot to visually monitor the integrity of the approach path.

C.1.3.4 Compliance does not affect the applicability of any of the requirements in the operating regulations (such as 14 CFR parts 91, 121, 125 and 135).

The EFVS does not change the approach minima prescribed in the standard instrument approach procedure being used; published minima still apply. (Refer to AC 90-106A for additional information.)

C.2 Features.

C.2.1 The EFVS can be used as a supplemental device to enhance the pilot's situational awareness during any phase of flight or operation in which its safe use has been established.

C.2.2 An EFVS image can provide an enhanced image of the scene that can compensate for any reduction in the clear outside view of the visual field framed by the HUD combiner.

The pilot must be able to use this combination of information seen in the image, and the natural view of the outside scene seen through the image, as safely and effectively as

Appendix C C-2 the pilot would use a 14 CFR §§ 23/25/27/29.773-compliant pilot compartment view without an EVS image.

C.2.3 14 CFR §§ 23/25/27/29.1301, Equipment: Function and installation, and 14 CFR §§ 23/25/27/29.1309, Equipment, systems, and installations, address certain image characteristics, installation, demonstration, and system safety.

C.2.3.1 Image characteristics criteria include:

 Resolution  Luminance  Luminance uniformity  Low level luminance  Contrast variation  Display quality  Display dynamics (for example, jitter, flicker, update rate, and lag) and  Brightness controls C.2.3.2 Installation criteria address:

 Visibility and access to EFVS controls  Integration of EFVS in the cockpit C.3 Demonstration.

The EFVS demonstration criteria address the flight and environmental conditions that should to be covered.

C.3.1 The EFVS imagery on the HUD must not degrade the safety of flight, nor interfere with the effective use of outside visual references for required pilot tasks, during any phase of flight in which it is used.

C.3.2 To avoid unacceptable interference with the safe and effective use of the pilot compartment view, the EFVS device should meet the following criteria:

C.3.2.1 The EFVS design should minimize unacceptable display characteristics or artifacts (for example, noise, “burlap” overlay, running water droplets) that obscure the desired image of the scene, impair the pilot's ability to detect and identify visual references, mask flight hazards, distract the pilot, or otherwise degrade task performance or safety.

C.3.2.2 Control of EFVS display brightness should be sufficiently effective, in dynamically changing background (ambient) lighting conditions, to prevent full or partial blooming of the display that would distract the pilot,

Appendix C C-3 impair the pilot's ability to detect and identify visual references, mask flight hazards, or otherwise degrade task performance or safety. If automatic control for image brightness is not provided, it should be shown that a single manual setting is satisfactory.

C.3.2.3 The EFVS controls, except those located on the pilot’s control wheel, should be adequately illuminated for all normal background lighting conditions, and should not create any objectionable reflections on the HUD or equivalent display or other flight instruments. There must be a means to allow the pilot using the display to immediately deactivate and reactivate the vision system imagery, on demand, without removing the pilot’s hands from the primary flight and power controls, or their equivalent. (Ref 14 CFR §§ 23.773(c)(3), 25.775(e)(3), 27.773(c)(3), and

29.773(c)(3)).

C.3.2.4 The EFVS image on the HUD should not impair the pilot's use of guidance information nor degrade the presentation and pilot awareness of essential flight information displayed on the HUD, such as alerts, airspeed, attitude, altitude and direction, approach guidance, windshear guidance, TCAS resolution advisories, and unusual attitude recovery cues.

C.3.2.5 The EFVS image should be sufficiently aligned and conformal to both the external scene and conformal HUD symbology so as not to be misleading, cause pilot confusion, or increase workload.

C.3.2.6 The safety and performance of the pilot tasks associated with the use of the pilot compartment view must not be degraded by the display of the EFVS image. Pilot tasks that must not be degraded by the EFVS image include:

 Detection, accurate identification, and maneuvering, as necessary, to avoid traffic, terrain, obstacles, and other hazards of flight.

 Accurate identification and use of visual references required for every task relevant to the phase of flight.

C.3.2.7 Compliance with these criteria does not affect the applicability of any of the requirements in the operating regulations (for example, 14 CFR parts 91, 121, 125, and 135). The criteria must be of a kind and design appropriate to the following functions:

 Present an image to aid the pilot during the approach.

 Display an image that the pilot can use to detect and identify the "visual references for the intended runway" required by 14 CFR §

91.176 to continue the approach to 100 feet height above touchdown (HAT) under EFVS Approach System operations or all the way to touchdown and rollout under EFVS Landing System operations.

Appropriate limitations should be included in the Operating

Appendix C C-4 Limitations section of the Airplane Flight Manual to prohibit the use of the EFVS for functions not found to be acceptable.

C.4 In addition to the sensor imagery, at least the following specific aircraft flight information must be displayed:

 Airspeed  Vertical speed;

 Aircraft attitude;

 Heading;

 Altitude;

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

 Path deviation indications;

 Flight path vector; and  Flight path angle reference cue.

 Radio altitude (For systems seeking EFVS Landing System credit)  Flare prompt or flare guidance for aircraft other than rotorcraft (For systems seeking EFVS Landing System credit) C.5 Head-Up Display. An EFVS used to conduct operations under 14 CFR §§ 91.176,

121.651, 125.381, and 135.225 must have an FAA type design approval. For a foreignregistered aircraft, the aircraft must meet all of the requirements in 14 CFR § 91.176, including the equipment requirements, in order to be used in EFVS operations in the United States. Under 14 CFR § 91.176, an EFVS is an installed airborne system which includes:

 The display element, which is a HUD or an equivalent display, that presents the features and characteristics required by the regulations such that they are clearly visible to the pilot flying in his or her normal position and line of vision looking forward along the flight path.

 Sensors that provide a real-time image of the forward external scene topography, as described above.

 Computers and power supplies.

 Indications.

 Controls.

Appendix D D-1 APPENDIX D. SAMPLE EFVS APPROACH SYSTEM FLIGHT TEST CONSIDERATIONS D.1 General Flight Test Considerations.

D.1.1 The objectives of the flight test program are to ensure that the system performs its intended function when installed, and to demonstrate that the EFVS Approach System is operationally acceptable and safe. The objectives of the flight test program are not to quantitatively measure the detection performance of the sensor. However, for EFVS Approach Systems installed on aircraft that are intended to conduct 14 CFR part 121, 125, and 135 operations the applicant should document the EFVS Approach System’s demonstrated performance and the environmental conditions in which the performance was demonstrated. The additional documentation of the system’s demonstrated performance is necessary for the 14 CFR part 121,125, and 135 operators to be granted operational approval from Flight Standards to conduct EFVS operations to 100 feet above the TDZE. See AC 90-106A for further information regarding the operational approval process required for conducting EFVS operations to 100 feet above the TDZE.

D.1.2 At the end of the flight test program, the EFVS Approach System should have demonstrated it is capable of imaging the required visual references before they are visible out the window using natural vision. The EFVS should enable descent below DA/DH or MDA using enhanced flight visibility when visual references would not otherwise be visible using natural vision at an altitude no lower than DA/DH or MDA.

D.1.3 The combination of the EFVS Approach System imagery with the HUD symbology and the relationship between the two in terms of brightness and contrast is a critical issue with respect to the installation; therefore, for the purpose of certification flight testing, the environmental conditions chosen should be such that these parameters are adequately evaluated.

D.1.4 Environmental conditions should be chosen to exercise both the automatic and manual control of items such as brightness, contrast, and gain, and any other parameter that affects the image displayed to the pilot.

D.2 Minimum Flight Test Conditions Observed.

D.2.1 Testing should include an appropriate number of fault-free approaches (see note below) in as many of the conditions listed below as practicable and as applicable. Past experience has shown that more than 50 fault-free approaches are needed to demonstrate than an EFVS adequately performs its intended function. The list below should be assessed against the specific sensor type. Additional test conditions can be specified.

 Night VFR conditions over various topography (urban, rural, snow covered, etc.).

 Day and night IFR conditions over various topography.

 Representative levels of rainfall.

Appendix D D-2  Representative levels of snowfall.

 Representative levels of fog.

 Haze.

 Representative sun angles.

 Representative airport lighting configurations.

 Representative airport/runway surface conditions (dry, wet, standing water, snow cover).

 Representative thermal crossover conditions.

 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.).

 Representative instrument approaches for the intended EFVS operations.

Note: A successful go-around due to lack of either enhanced vision from the DH/DA or natural vision at 100 ft above TDZE, does not constitute a faulted approach. A faulted approach is if:

o HUD or EFVS Approach System failure has occurred.

o 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.

o At 100 ft above TDZE the aircraft is not positioned so that the cockpit is within, and tracking so as to remain within, the lateral confines of the runway extended.

o Due to a confusing or misaligned image, the touchdown will be too short or too long.

o The EFVS Approach System image degrades the fly-ability of the display such that a successful approach to DA/DH or MDA/MDH is not possible.

D.3 Test Points Testing should include all phases of flight for which the applicant seeks approval of the system. In addition to the success criteria for approaches, the EFVS Approach System minimum performance standards require the assessment of the HUD/EFVS Approach System display when used in conjunction with the flight instrumentation required in 14 CFR § 91.176 and listed in chapter 4, paragraph 4.5.1.3 of this AC. The following evaluations should be performed in representative configurations. (The pilot evaluation matrix is at the end of this appendix.)

Appendix D D-3 D.4 Evaluation During Taxi D.4.1 Assess EFVS Approach System/HUD combination while taxiing and making identification of objects on runways, taxiways, parking aprons.

D.4.2 Verify the use of EFVS Approach System does not cause confusion or misleading information when viewing through the HUD/EVS all types of airport runway, taxiway, obstruction, and barrier lighting, marking and signage as well as the navigation, taxi, and landing lights of other aircraft.

D.4.3 Verify the HUD combiner, with the image displayed, does not significantly alter the color perception of the external scene.

D.4.4 Assess lack of burn-in or blooming from high intensity heat sources such as operating (running) engines, etc.

D.5 Take off Evaluation D.5.1 Ensure correct pitch angle is achieved using HUD pitch reference target.

D.5.2 Verify symbology in EFVS Approach System mode is clear, visible, and does not cause over-control or oscillations in acquiring and maintaining the required ground track.

D.5.3 Confirm the HUD with EFVS Approach System provides the pilot with a quick-glance (instant) sense of flight parameters.

D.5.4 Assess the transition to different selected vertical modes.

D.5.5 Evaluate the EFVS Approach System image during the take-off roll and throughout the climb segment, against the attributes listed in the pilot evaluation matrix.

D.6 Climb and Descent and Lateral Modes Evaluation D.6.1 Climb, descent, and lateral modes should be evaluated in day and night IMC and VMC to assess HUD/EFVS Approach System compatibility.

D.6.2 During vertical and lateral guidance maneuvers, evaluate the EFVS Approach System image against the attributes listed in the pilot evaluation matrix.

D.7 Instrument Approaches.

During any instrument approach for which approval is sought, HUD/EFVS Approach System compatibility should be evaluated against the attributes listed in the pilot evaluation matrix.

Appendix D D-4 D.8 Flare Landing and Go Around D.8.1 While using EFVS Approach System during final approach and through the flare (below 50 ft), touchdown roll or go-around, assess the transition to natural vision and compatibility of the guidance when following the HUD/EFVS Approach System flight cues.

D.8.2 Confirm landing rollout information, if provided in the display, is sufficiently visible to the pilot and does not cause over-control or oscillations in acquiring and maintaining the required ground track.

D.8.3 Throughout the approach guidance maneuvers, evaluate the EFVS Approach System image against the attributes listed in the pilot evaluation matrix.

D.9 Copilot Monitor A copilot monitor is not required by the FAA for operations within the United States.

However, if one is installed, the applicant should assess the ergonomic aspects of the image on the copilot’s EFVS Approach System monitor.

D.9.1 Verify satisfactory display of imagery in all lighting and environmental conditions and that dimming controls of the display are adequate.

D.9.2 If the display has dual purposes, verify the means of switching the display to being the EFVS Approach System monitor and back is satisfactory and clearly evident.

D.9.3 Verify no flicker and/or jitter in the display.

D.9.4 Verify no objectionable glare or reflections are generated by the display or are visible in the display.

D.9.5 Verify the co-pilot’s use of the EFVS Approach System monitor does not require undue head/body movement away from his/her normal scan pattern or his/her normal seated position.

D.10 Failure Cases.

Failure cases to support the FHA should be assessed as required, for example, uncommanded full image brightness, misaligned image, frozen image, etc. during the approaches required in this appendix.

D.11 Ice Protection System Evaluation D.11.1 If the EFVS Approach System sensor installation has ice protection capability, the EFVS Approach System image must be evaluated with the ice protection on and off in representative environmental conditions.

Appendix D D-5 D.11.2 Icing of the sensor fairing/radome must be appropriately assessed in accordance with the certified flight envelope.

D.12 Evaluation Matrix.

Table 6 contains the pilot’s evaluation matrix. The evaluation matrix should be used to support the testing described in this appendix. Additional evaluation points may be added to the test program depending on particular features and intended functions of the actual system being certified.

Table 6. EFVS Approach System Evaluation Matrix EFVS Approach System Evaluation Conditions A Confirm crew workload is not adversely affected by the HUD/ EFVS Approach System installation.

B Verify no adverse physiological effects from using the HUD/ EFVS Approach System (for example, fatigue, eye strain).

C Verify HUD/EFVS Approach System symbology is visible within pilot Field of View (FOV). (When viewed by both eyes from any off-center position within eye box, non -uniformities should not produce perceivable diff erences in binocular view.)

D Verify no jitter or flicker of HUD/EFVS Approach System symbology/image.

E Verify the EFVS Approach System image does not have noise, local disturbances or artifacts that distract from the use of the system.

F If HUD symbol ogy has been modified to accommodate the EFVS Approach System image, assess HUD guidance and ensure that introduction of EFVS Approach System does not induce lag in control symbols inducing Pilot Induced Oscillation (PIO).

G Verify the system is not adver sely affected by aircraft maneuvering or changes in attitudes encountered during the referenced environmental conditions.

H Ensure the required flight and navigation functions applicable for the phase of flight being evaluated are clearly displayed on the HUD with no unacceptable occlusions during testing.

I Verify the total data presented by the EFVS Approach System imagery and HUD symbology does not over clutter the HUD combiner display area.

Appendix D D-6 EFVS Approach System Evaluation Conditions J Assess the degree of obscuration of the pilot’s outside vi ew or field of view through the cockpit window as a result of EFVS Approach System imagery and HUD symbology.

K Confirm the pilot’s ability to detect hazards, maneuver, avoid traffic, terrain or other obstacles, is not impaired or degraded by the display of EFVS Approach System imagery.

L Confirm there is no discrepancy between the conformal HUD symbols, sensor image, and the outside view through the windshield.

M Verify outside visibility as viewed through combiner sensor imagery is adequately aligned and conformal to the external scene and HUD symbology.

N Confirm the EFVS Approach System imagery does not obscure the desired imagery of the scene, impair the pilot’s ability to detect and identify visual references, mask flight hazards, or distract the pilot.

O Assess the ease of operating the HUD with the sensor image displayed, during aircraft maneuvers and change in attitude, encountered in normal operations.

P Determine whether there is any glare or reflection that could interfere with the EFVS Approach System image either in day or night lighting conditions.

Q Determine if any impairment is experienced in the ability to use the display due to visible external surfaces within the HUD.

R Determine whether the sensor image displayed on the HUD combin er objectionably impairs the pilot compartment view.

S Assess impact of water droplets running across the sensor window to ensure that it does not distract the pilot or degrade his/her task performance or safety.

T Verify identification of approach lights, runway threshold, touchdown zone etc. as per 14 CFR § 91.176(b)(3).

U Confirm the HUD EFVS Approach System image is suitable and performs its intended function.

V Confirm the sensor image on the co -pilot’s display (if installed) is useable and performs its intended function.

W Evaluate the EFVS Approach System image during the takeoff roll and throughout the climb segment, against the attributes listed in the attached pilot evaluation matrix.