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20. Compliance with § 25.13298
a. General8
b. Relevant paragraphs8
21—26 [RESERVED]13
CHAPTER 3. FLIGHT GUIDANCE SYSTEM ENGAGEMENT,
DISENGAGEMENT, INDICATIONS, AND OVERRIDE14
27. Autopilot Engagement, Disengagement, and Indications14
a. Autopilot engagement14
(1) Single switch action14
(2) Engagement status of autopilot14
(3) Multiple autopilots14
(4) Acceptable transients14
(5) FD not engaged14
(6) FD engaged14
b. Autopilot disengagement15
(1) General15
(2) Autopilot disengagement alerts16
(3) Quick disengagement control16
(4) Alternative means of autopilot disengagement17
(5) Flightcrew pitch trim input17
28. FD Engagement, Disengagement, and Indications18
a. FD engagement18
(1) General18
(2) Guidance cue(s)19
(3) Reactive wind shear guidance system19
b. FD disengagement19
29. Autothrust Engagement, Disengagement, and Indications19
a. Autothrust engagement19
(1) Indication19
(2) Accessibility of controls19
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(3) Inadvertent engagement/disengagement19
(4) Automatic engagement19
b. Autothrust disengagement20
(1) Indication of disengagement20
(2) Inadvertent disengagement20
(3) Consequence of disengagement20
(4) Autothrust quick disengagement control20
30. Override of the FGS21
a. General21
b. Autopilot override21
(1) With automatic disengagement21
(2) Without automatic disengagement21
c. Autothrust override22
(1) Force required22
(2) Response to override22
(3) Engagement status with override22
31. FGS Engagement Mode Compatibility22
a. FGS mode engagement philosophy22
b. Engagement mode compatibility23
32—41 [RESERVED]23
CHAPTER 4. CONTROLS, INDICATIONS, AND ALERTS24
42. General24
a. Human-machine interface (HMI)24
b. Design of controls, indications, and alerts24
c. Evaluation of information provided by FGS24
43. FGS Controls24
a. General24
b. Design considerations24
(1) Differentiation of knob shape and position24
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(2) Design to support correct selection of target values24
(3) Commonality across aircraft types25
(4) Positioning of controls and related indications25
(5) Inadvertent operation25
44. FGS Mode Selection, Annunciation, and Indication25
a. Annunciation of engagement of the FGS25
b. Description of FGS modes25
c. FGS mode annunciations25
(1) Active and armed modes25
(2) Location25
(3) Discriminators26
(4) Color26
d. Mode changes26
(1) Operationally relevant mode changes26
(2) Attention-getting features26
(3) Use of alerts26
e. Failure to engage or arm26
f. FGS mode display and indications26
45. FGS Alerting, Warning, Caution, Advisory, and Status27
a. General27
(1) Alerting provisions27
(2) Determination of FGS capability27
b. Speed protection alerts27
(1) Alerts to crew27
(2) Alert specifications27
(3) Consistency27
(4) Nuisance alerts27
c. Loss of autopilot approach mode27
d. Awareness of potential significant transient condition (“bark before bite”)28
(1) General28
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(2) Flightcrew alert(s)28
(3) Situations to consider for an alert28
46. FGS Considerations for HUDs29
a. General29
b. Characteristics of HUD guidance29
(1) Supplemental use display system29
(2) External visual references29
(3) Interference and occlusion30
(4) Display criteria30
(5) Conformal symbology30
(6) Low-visibility approach30
(7) Clutter30
c. HUD/HDD compatibility30
(1) General30
(2) Consistency and compatibility30
d. Alerting issues31
(1) Alerts displayed on HUDs31
(2) Monochrome HUDs32
(3) Multicolor HUDs32
(4) Single HUD installation32
(5) Dual HUD installations32
(6) GPWS/TCAS on HUD32
e. Upset/unusual attitude recovery guidance32
(1) Guidance cues32
(2) Orientation cues33
47—51 [RESERVED]33
CHAPTER 5. PERFORMANCE OF FUNCTION34
52. General34
a. Intended function34
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b. Effect of system tolerances34
53. Normal Performance34
a. General34
b. Conditions to consider34
c. Level of performance36
(1) Significant characteristics36
(2) Configuration changes36
(3) Compliance evaluation36
(4) Prescribed levels of performance36
(5) Equivalence of performance36
(6) Autopilot36
(7) FD36
(8) Autothrust36
(9) Automatic trim36
54. Performance in Rare Normal Conditions37
a. General37
(1) Range of conditions37
(2) Effect on performance37
b. Conditions to consider37
c. Level of performance38
(1) Performance standard38
(2) Autopilot authority limit39
(3) Masking of potential hazard39
55. Icing Considerations in Normal and Rare Normal Conditions39
a. Effect on performance39
b. Alerts39
c. Effect on speed protection39
56. Performance in Non-Normal Conditions39
a. General39
b. Conditions to consider39
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c. Level of performance40
(1) Performance standard40
(2) Autopilot authority limit40
(3) Masking of potential hazard41
57. Speed Protection41
a. General41
(1) Speed excursions41
(2) Compliance with § 25.1329(h)41
(3) Design standard42
b. Low-speed protection42
(1) General42
(2) Factors to consider42
(3) Low-speed protection during approach operations43
(4) Wind shear recovery guidance44
c. High-speed protection44
(1) General44
(2) Factors to consider44
58—61 [RESERVED]45
CHAPTER 6. CHARACTERISTICS OF SPECIFIC MODES46
62. General46
63. Lateral Modes46
a. Heading or track hold46
b. Heading or track select46
c. LNAV mode46
(1) Lateral flightpath46
(2) Automatic mode transitions46
(3) TOGA46
64. Vertical Modes47
a. Target altitude selection47
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b. Vertical speed47
c. Flightpath angle47
d. Indicated airspeed/Mach hold (speed on elevator)47
e. Indicated airspeed/Mach select (speed on elevator)47
f. Flight level (FL) change (speed on elevator)47
g. Altitude capture47
(1) Mode transition47
(2) Guidelines for altitude capture mode48
h. Altitude hold49
(1) Entering mode49
(2) Mode transition annunciation49
(3) Barometric pressure adjustment49
i. VNAV49
(1) FMS path49
(2) Climb or descent49
65. Multiaxis Modes50
a. Takeoff mode50
(1) Vertical guidance50
(2) Lateral guidance50
(3) Rotation guidance50
(4) Autothrust50
(5) Operation and performance50
b. Go-around mode51
(1) Vertical elements51
(2) Speed51
(3) Autothrust51
(4) Engagement52
(5) All engine and engine-out capability52
c. Approach mode52
(1) Final approach path52
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(2) Mode annunciations52
(3) Submodes52
(4) Mode engagement sequence52
66. Autothrust Modes52
a. Thrust mode52
b. Speed mode53
c. Retard mode53
67. Special Considerations for VNAV Approach Operations Related to Selecting a
Target Altitude53
a. Approach operations53
b. VNAV path operations53
68. Control Wheel Steering (Control Steering through the Autopilot)53
a. General53
b. Design53
(1) Control forces53
(2) Bank and pitch attitudes53
(3) Control behavior54
(4) Stall and stall recovery54
(5) Adjustments to trim54
(6) Takeoff and landing54
(7) Automatic reversion to CWS mode54
c. Terminology and application of advisory material54
(1) Touch control steering (TCS)55
(2) Supervisory override55
69. Special Considerations for the Integration of Fly-by-Wire Flight Control Systems
and FGS55
a. Speed protection55
b. System degradation55
70—74 [RESERVED]55
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CHAPTER 7. FLIGHT GUIDANCE SYSTEM INTEGRATION56
75. General56
76. System Integration Issues56
a. Common and cascading failure modes56
b. Risk of error56
c. System safety analysis56
77. Functional Interfaces56
a. Interfacing sensors56
b. Potential inconsistencies between systems57
c. Function and performance57
78—82 [RESERVED]57
CHAPTER 8. SAFETY ASSESSMENT58
83. General58
a. Basic safety requirements58
b. Safety assessment58
c. Validation of safety assessment58
d. Coordination with the FAA58
84. FGS Failure Conditions58
a. Functionality58
b. Effect of failure condition59
85. Type and Severity of Failure Conditions59
a. Types of failure conditions59
(1) Loss of function59
(2) Malfunction59
b. Cause59
c. Severity60
d. Assessment of failure conditions60
(1) Functional failures60
(2) Airframe loads60
(3) Assessing total effect of failure60
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86. Mitigation of Failure Conditions60
a. General60
b. Identification of methods61
c. FGS deselection61
87. Validation of Failure Conditions61
a. General61
b. Validation options61
c. Validation methodology61
88. Specific Considerations62
a. FGS action during ground operations62
b. FGS operations in close proximity to the ground62
(1) Takeoff62
(2) Approach63
c. Cruise operations64
d. Asymmetric thrust during autothrust operation64
89. Failure to Disengage the FGS65
90—97 [RESERVED]65
CHAPTER 9. COMPLIANCE DEMONSTRATION USING FLIGHT TEST AND
SIMULATION66
98. General66
a. Methods of compliance demonstration66
b. Criteria for establishing compliance66
c. Elements of certification flight test66
d. Pilot-in-the-loop evaluation66
e. Other applicable guidance material for FGS takeoff and/or approach modes66
(1) Criteria to consider66
(2) Procedures to show compliance67
f. Relationship of AC chapters67
99. Performance Demonstration (Fault Free): § 25.130167
a. General67
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(1) Certification plan67
(2) Evaluating performance68
(3) Evaluating compatibility of mode controls, indications, and alerts68
b. Normal performance68
(1) Demonstration68
(2) Evaluation68
(3) Expected errors68
c. Performance in “other than normal” conditions68
(1) Test program68
(2) Evaluation of FGS69
(3) Additional guidance for wind shear69
d. Specific performance conditions69
(1) Icing considerations69
(2) Low-speed protection70
(3) High-speed protection70
(4) Go-around70
(5) Steep approach (special authorization)71
(6) Indication of and response to an out-of-trim condition72
e. FD/HUD72
(1) General72
(2) Specific demonstrations for HUD73
(3) Simulator demonstration for HUD74
f. Flightcrew override of the FGS75
(1) Autopilot override75
(2) Autothrust override75
(3) Pitch trim system evaluation during autopilot override75
100. Failure Conditions Requiring Validation: § 25.130976
a. General76
(1) Safety assessment76
(2) Evaluation of failure conditions76
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b. Validation elements76
(1) Assessment76
(2) Failure condition76
(3) Pilot recognition77
(4) Pilot reaction time78
(5) Pilot recovery79
c. Takeoff79
(1) Worst-case failure condition79
(2) Failures to be evaluated79
(3) On runway guidance79
d. Climb, cruise, descent, and holding79
e. Maneuvering79
f. Approach79
(1) Approach with vertical path reference80
(2) Approach without vertical path reference81
(3) Steep approach81
g. Specific conditions81
(1) Failure conditions to be evaluated81
(2) Failure to disengage81
101. Criteria Supporting Operational Use of Autopilot81
a. Typical flight operations81
b. Operations in close proximity to the ground82
(1) General82
(2) Considerations82
(3) Autopilot engagement altitude/height after takeoff82
(4) Autopilot engagement during approach83
(5) Circling approach85
c. Climb, cruise, descent, and holding85
d. Maneuvering85
102. Automatic Disengagement of the Autopilot85