Appendix A A-3 14 CFR § Description Acceptable Method of Compliance 23/25/27/29.1301 Function and installation Ground Test and Flight Test
25.1302 Installed systems and equipment for use by the flightcrew Analysis, Simulation, Flight Test 23/25/27/29.1309 Equip, systems, and install Analysis and/or Test and Design data
25.1316 System lightning protection Analysis and Ground Test
23.1308, and 25/27/29.1317 High-intensity Radiated Fields (HIRF) Protection Ground Test and Flight Test Analysis/Data 23/25/27/29.1321 Arrangement and visibility Ground Test and Flight Test 23/25/27/29.1322 Warning, caution, advisory lights Ground Test and Flight Test
25.1323 Airspeed indicating systems Flight Test 23/27/29.1335 Flight director systems Ground Test and Flight Test 23/27.1351 Electrical Systems and Equipment; General Analysis 25/29.1353 Electrical equipment and installation Analysis 23/25/27/29.1357 Circuit protective devices Analysis and Ground Test 23/25/27/29.1381 Instrument lights Ground Test and Flight Test 23/25/27/29.1419 Ice protection Analysis 23/25/29.1431(a)(c) Electronic equipment Analysis and Ground Test 23/25/27/29.1459(e) Flight data recorders Flight test
Appendix A A-4 14 CFR § Description Acceptable Method of Compliance 23/25/27/29.1501 Operating Limitations and Information; General Flight Test 23/25/27/29.1523 Minimum flight crew Flight Test or Simulation 23/25/27/29.1525 Kinds of operation Flight Test 23/25/27/29.1529 Instructions for Continued Airworthiness Design Data 23/25/27/29.1581 Aircraft flight manual; General Design Data and Flight Test 23/25/27/29.1583 Operating limitations Flight Test Data 23/25/27/29.1585 Operating procedures Flight Test Data
26.47 Holders of and applicants for a supplemental type certificate - alterations and repairs to alterations.
Analysis Note: In some cases, previously approved test data for the aircraft may be resubmitted for compliance, if analysis can establish that the test data remains valid for the aircraft with the new modification.
Appendix B B-1 APPENDIX B. EFVS APPROACH SYSTEM AND EFVS LANDING SYSTEM SAFETY
GUIDANCE B.1 General.
B.1.1 Safety Criteria. Safety criteria for approach and landing systems generally consider four elements: accuracy, continuity, availability, and integrity. These criteria apply to both the external navigation systems as well as airborne navigation equipment.
Trajectory management or flight technical error, which can be interpreted as signal structure contributing to roughness, bends and scalloping of ILS-based guidance, should also be considered. They also define how the airspace and aircraft are integrated together to make a safe approach and landing. The FAA developed, in conjunction with the other governments, definitions related to safety and performance for a landing system.
B.1.2 Transport Category Airplanes. For aircraft systems, 14 CFR § 25.1309 defines the safety requirement and AC 25.1309-1A defines the means for verification. The probability of each catastrophic failure condition must be 10 -9 or less per flight hour considering any mode of flight, any combination of failures causing an unsafe condition, and including the probability of the crew to cope with the failures. The FAA accepts this number to assure a negligible adverse effect on accident rates, and to help reduce them as new systems come on line.
B.1.3 General Aviation or Non-Transport Category Airplanes. Similar information can be found in 14 CFR 23.1309 and AC 23.1309. The relationship among airplane classes, probabilities, severity of failure conditions, and software development assurance levels is found in AC 23.1309-1E.
B.1.4 Rotorcraft. Similar information can be found in 14 CFR § 27.1309 and AC 27-1B and 14 CFR § 29.1039 and AC 29-2C.
B.2 Required Level of Safety.
The required level of safety for any aircraft systems, therefore, depends on the ability of the crew to cope with failures as shown in Table 4, which lists the categories of systems and failure probabilities to meet the safety criteria in 14 CFR parts 23 and 25 airplanes.
For part 23 airplanes, similar information can be found in 14 CFR § 23.1309 and AC
23.1309-1E. The relationship among airplane classes, probabilities, severity of failure conditions and software development assurance levels is found in AC 23.1309-1E.
Appendix B B-2 Table 4. Required Level of Safety, 14 CFR part 25 Aircraft Classification Effect Target Probability P Minor Slight reduction in safety margins or functional capabilities.
Slight increase in crew workload.
Some inconvenience to occupants.
10-3 > P > 1-5 Major Significant reduction in safety margins or functional capabilities.
Significant increase in crew workload or in conditions impairing crew efficiency.
Some discomfort to occupants.
10-5 > P > 1-7 Hazardous/ S e v e r e
M a j o r
Large reduction in safety margins or functional capabilities.
Higher workload or physical distress such that the crew could not be relied upon to perform tasks accurately or completely.
Adverse effects upon occupants including serious or fatal injury to a relatively small number of occupants other than the flight crew.
10-7 > P > 1-9 Catastrophic Failure conditions which would prevent continued safe flight and landing, resulting in multiple fatalities, usually with the loss of the airplane.
10-9 > P B.3 Demonstration.
To meet the safety criteria, the EFVS design will be demonstrated through analysis and engineering tests to preclude any critical failure combinations that can cause hazardously misleading information to be presented to the crew, or which can otherwise subsequently cause an unsafe condition. Failures which are self-evident or made obvious to the crew, and with which they can safely cope, need not be specifically monitored.
B.4 State Data.
The aircraft state data are provided by the standard inertial, air data, and radio guidance sensors.
The HUD or display processor will be required to be at a sufficient level of safety for the aircraft type and application to detect critical random or common faults that could otherwise cause an unsafe condition. The ability to continue the approach below the standard Category I
Appendix B B-3 DA/DH/MDA/MDH into the visual segment therefore is strictly borne by the pilot, a safety factor already accounted for in the safety analysis for standard Category I operations. The example below in Table 5 is a model case and cannot be applied for any specific aircraft.
Functional hazard assessments as required by the FAA are aircraft and systems specific.
Table 5. Example EFVS/HUD Functional Hazard Assessment, 14 CFR part 25 Aircraft, ILS Approaches to 100 ft Height Above Touchdown, RVR 1200 ft FHA NO.
FAILURE
CONDITION PHASE OF FLIGHT PILOT ACTION HAZARD
INDEX OBJECTIVE
1.0 LOSS OF
FUNCTION
1.1 Loss of EFVS imagery on HUD Taxi and Takeoff Enroute Terminal Arrival Final Approach - Above 100 ft. EFVS height above touchdown zone elevation Go-Around Crew would revert to standard headup and/or head down procedures MINOR 10-3
1.2 Loss of 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 MINOR 10-3
1.3 Loss of HUD symbology Taxi and Takeoff 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
1.4 Loss of HUD symbology Final Approach - From 100 ft. height above touchdown zone elevation to Landing Pilot would continue the approach and land MINOR 10-3
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.