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Electronic Code of Federal Regulations

e-CFR data is current as of April 2, 2020

Title 14Chapter ISubchapter GPart 121 → Appendix


Title 14: Aeronautics and Space
PART 121—OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS


Appendix M to Part 121—Airplane Flight Recorder Specifications

The recorded values must meet the designated range, resolution and accuracy requirements during static and dynamic conditions. Dynamic condition means the parameter is experiencing change at the maximum rate attainable, including the maximum rate of reversal. All data recorded must be correlated in time to within one second.

ParametersRangeAccuracy (sensor input)Seconds per sampling intervalResolutionRemarks
1. Time or relative times counts.124 Hrs, 0 to 4095±0.125% per hour41 secUTC time preferred when available. Count increments each 4 seconds of system operation.
2. Pressure Altitude−1000 ft to max certificated altitude of aircraft. + 5000 ft±100 to ±700 ft (see table, TSO C124a or TSO C51a)15 to 35Data should be obtained from the air data computer when practicable.
3. Indicated airspeed or Calibrated airspeed50 KIAS or minimum value to Max Vso to 1.2 V. D±5% and ±3%11 ktData should be obtained from the air data computer when practicable.
4. Heading (Primary flight crew reference)0-360° and Discrete “true” or “mag”±2°10.5°When true or magnetic heading can be selected as the primary heading reference, a discrete indicating selection must be recorded.
5. Normal acceleration (vertical)9−3g to + 6g±1% of max range excluding datum error of ±5%0.1250.004g
6. Pitch Attitude±75°±2°1 or 0.25 for airplanes operated under §121.344(f)0.5°A sampling rate of 0.25 is recommended.
7. Roll attitude2±180°±2°1 or 0.5 for airplanes operated under §121.344(f)0.5A sampling rate of 0.5 is recommended.
8. Manual Radio Transmitter Keying or CVR/DFDR synchronization referenceOn-Off (Discrete)
None
1Preferably each crew member but one discrete acceptable for all transmission provided the CVR/FDR system complies with TSO C124a CVR synchronization requirements (paragraph 4.2.1 ED-55).
9. Thrust/power on each engine—primary flight crew referenceFull range forward±2%1 (per engine)0.3% of full rangeSufficient parameters (e.g. EPR, N1 or Torque, NP) as appropriate to the particular engine being recorded to determine power in forward and reverse thrust, including potential overspeed condition.
10. Autopilot EngagementDiscrete “on” or “off”1
11. Longitudinal Acceleration±1g±1.5% max. range excluding datum error of ±5%0.250.004g
12a. Pitch control(s) position (nonfly-by-wire systems).18Full Range±2° unless higher accuracy uniquely required0.5 or 0.25 for airplanes operated under §121.344(f)0.5% of full rangeFor airplanes that have a flight control breakaway capability that allows either pilot to operate the controls independently, record both control inputs. The control inputs may be sampled alternately once per second to produce the sampling interval of 0.5 or 0.25, as applicable.
12b. Pitch control(s) position (fly-by-wire systems).3 18Full Range±2° unless higher accuracy uniquely required0.5 or 0.25 for airplanes operated under §121.344(f)0.2% of full range
13a. Lateral control position(s) (nonfly-by-wire).18Full Range±2° unless higher accuracy uniquely required0.5 or 0.25 for airplanes operated under §121.344(f)0.2% of full rangeFor airplanes that have a flight control breakaway capability that allows either pilot to operate the controls independently, record both control inputs. The control inputs may be sampled alternately once per second to produce the sampling interval of 0.5 or 0.25, as applicable.
13b. Lateral control position(s) (fly-by-wire).4 18Full Range±2° unless higher accuracy uniquely required0.5 or 0.25 for airplanes operated under §121.344(f)0.2% of full range.
14a. Yaw control position(s) (nonfly-by-wire).5 18Full Range±2° unless higher accuracy uniquely required0.50.3% of full rangeFor airplanes that have a flight control breakaway capability that allows either pilot to operate the controls independently, record both control inputs. The control inputs may be sampled alternately once per second to produce the sampling interval of 0.5.
14b. Yaw control position(s) (fly-by-wire).18Full Range±2° unless higher accuracy uniquely required0.50.2% of full range
15. Pitch control surface(s) position.6 18Full Range±2° unless higher accuracy uniquely required0.5 or 0.25 for airplanes operated under §121.344(f)0.3% of full rangeFor airplanes fitted with multiple or split surfaces, a suitable combination of inputs is acceptable in lieu of recording each surface separately. The control surfaces may be sampled alternately once per second to produce the sampling interval of 0.5 or 0.25, as applicable.
16. Lateral control surface(s) position.7 18Full Range±2° unless higher accuracy uniquely required0.5 or 0.25 for airplanes operated under §121.344(f)0.3% of full rangeA suitable combination of surface position sensors is acceptable in lieu of recording each surface separately. The control surfaces may be sampled alternately to produce the sampling interval of 0.5 or 0.25, as applicable.
17. Yaw control surface(s) position.8 18Full Range±2° unless higher accuracy uniquely required0.50.2% of full rangeFor airplanes with multiple or split surfaces, a suitable combination of surface position sensors is acceptable in lieu of recording each surface separately. The control surfaces may be sampled alternately to produce the sampling interval of 0.5.
18. Lateral Acceleration±1g±1.5% max. range excluding datum error of ±5%0.250.004g
19. Pitch Trim Surface PositionFull Range±3° Unless Higher Accuracy Uniquely Required10.6% of full range
20. Trailing Edge Flap or Cockpit Control Selection.10Full Range or Each Position (discrete)±3° or as Pilot's indicator20.5% of full rangeFlap position and cockpit control may each be sampled at 4 second intervals, to give a data point every 2 seconds.
21. Leading Edge Flap or Cockpit Control Selection.11Full Range or Each Discrete Position±3° or as Pilot's indicator and sufficient to determine each discrete position20.5% of full rangeLeft and right sides, or flap position and cockpit control may each be sampled at 4 second intervals, so as to give a data point every 2 seconds.
22. Each Thrust Reverser Position (or equivalent for propeller airplane)Stowed, In Transit, and Reverse (Discrete)1 (per engine)Turbo-jet—2 discretes enable the 3 states to be determined.
Turbo-prop—discrete.
23. Ground spoiler position or brake selection12Full range or each position (discrete)±2° Unless higher accuracy uniquely required1 or 0.5 for airplanes operated under §121.344(f)0.5% of full range
24. Outside Air Temperature or Total Air Temperature.13−50 °C to + 90 °C±2 °C20.3 °C
25. Autopilot/Autothrottle/AFCS Mode and Engagement StatusA suitable combination of discretes1Discretes should show which systems are engaged and which primary modes are controlling the flight path and speed of the aircraft.
26. Radio Altitude14−20 ft to 2,500 ft±2 ft or ±3% whichever is greater below 500 ft and ±5% above 500 ft11 ft + 5% above 500 ftFor autoland/category 3 operations. Each radio altimeter should be recorded, but arranged so that at least one is recorded each second.
27. Localizer Deviation, MLS Azimuth, or GPS Latitude Deviation±400 Microamps or available sensor range as installed
±62°
As installed ±3% recommended10.3% of full rangeFor autoland/category 3 operations. Each system should be recorded but arranged so that at least one is recorded each second. It is not necessary to record ILS and MLS at the same time, only the approach aid in use need be recorded.
28. Glideslope Deviation, MLS Elevation, or GPS Vertical Deviation±400 Microamps or available sensor range as installed
0.9 to + 30°
As installed + /3−3% recommended10.3% of full rangeFor autoland/category 3 operations. Each system should be recorded but arranged so that at least one is recorded each second. It is not necessary to record ILS and MLS at the same time, only the approach aid in use need be recorded.
29. Marker Beacon PassageDiscrete “on” or “off”1A single discrete is acceptable for all markers.
30. Master WarningDiscrete1Record the master warning and record each “red” warning that cannot be determined from other parameters or from the cockpit voice recorder.
31. Air/ground sensor (primary airplane system reference nose or main gear)Discrete “air” or “ground”1 (0.25 recommended)
32. Angle of Attack (If measured directly)As installedAs installed2 or 0.5 for airplanes operated under §121.344(f)0.3% of full rangeIf left and right sensors are available, each may be recorded at 4 or 1 second intervals, as appropriate, so as to give a data point at 2 seconds or 0.5 second, as required.
33. Hydraulic Pressure Low, Each SystemDiscrete or available sensor range, “low” or “normal”±5%20.5% of full range
34. GroundspeedAs InstalledMost Accurate Systems Installed10.2% of full range
35. GPWS (ground proximity warning system)Discrete “warning” or “off”1A suitable combination of discretes unless recorder capacity is limited in which case a single discrete for all modes is acceptable.
36. Landing Gear Position or Landing gear cockpit control selectionDiscrete4A suitable combination of discretes should be recorded.
37. Drift Angle.15As installedAs installed40.1°
38. Wind Speed and DirectionAs installedAs installed41 knot, and 1.0°
39. Latitude and LongitudeAs installedAs installed40.002°, or as installedProvided by the Primary Navigation System Reference. Where capacity permits Latitude/longitude resolution should be 0.0002°.
40. Stick shaker and pusher activationDiscrete(s) “on” or “off”1A suitable combination of discretes to determine activation.
41. Windshear DetectionDiscrete “warning” or “off”1
42. Throttle/power Leverl position.16Full Range±2%1 for each lever2% of full rangeFor airplanes with non-mechanically linked cockpit engine controls.
43. Additional Engine ParametersAs installedAs installedEach engine each second2% of full rangeWhere capacity permits, the preferred priority is indicated vibration level, N2, EGT, Fuel Flow, Fuel Cut-off lever position and N3, unless engine manufacturer recommends otherwise.
44. Traffic Alert and Collision Avoidance System (TCAS)DiscretesAs installed1A suitable combination of discretes should be recorded to determine the status of—Combined Control, Vertical Control, Up Advisory, and Down Advisory. (ref. ARINC Characteristic 735 Attachment 6E, TCAS VERTICAL RA DATA OUTPUT WORD.)
45. DME 1 and 2 Distance0-200 NMAs installed41 NM1 mile
46. Nav 1 and 2 Selected FrequencyFull RangeAs installed4Sufficient to determine selected frequency
47. Selected barometric settingFull Range±5%(1 per 64 sec.)0.2% of full range
48. Selected AltitudeFull Range±5%1100 ft
49. Selected speedFull Range±5%11 knot
50. Selected MachFull Range±5%1.01
51. Selected vertical speedFull Range±5%1100 ft/min
52. Selected headingFull Range±5%1
53. Selected flight pathFull Range±5%1
54. Selected decision heightFull Range±5%641 ft
55. EFIS display formatDiscrete(s)4Discretes should show the display system status (e.g., off, normal, fail, composite, sector, plan, nav aids, weather radar, range, copy.
56. Multi-function/Engine Alerts Display formatDiscrete(s)4Discretes should show the display system status (e.g., off, normal, fail, and the identity of display pages for emergency procedures, need not be recorded.
57. Thrust command.17Full Range±2%22% of full range
58. Thrust targetFull Range±2%42% of full range
59. Fuel quantity in CG trim tankFull Range±5%(1 per 64 sec.)1% of full range
60. Primary Navigation System ReferenceDiscrete GPS, INS, VOR/DME, MLS, Localizer Glideslope4A suitable combination of discretes to determine the Primary Navigation System reference.
61. Ice DetectionDiscrete “ice” or “no ice”4
62. Engine warning each engine vibrationDiscrete1
63. Engine warning each engine over tempDiscrete1
64. Engine warning each engine oil pressure lowDiscrete1
65. Engine warning each engine over speedDiscrete1
66. Yaw Trim Surface PositionFull Range±3% Unless Higher Accuracy Uniquely Required20.3% of full range
67. Roll Trim Surface PositionFull Range±3% Unless Higher Accuracy Uniquely Required20.3% of full range
68. Brake Pressure (left and right)As installed±5%1To determine braking effort applied by pilots or by autobrakes.
69. Brake Pedal Application (left and right)Discrete or Analog “applied” or “off”±5% (Analog)1To determine braking applied by pilots.
70. Yaw or sideslip angleFull Range±5%10.5°
71. Engine bleed valve positionDiscrete “open” or “closed”4
72. De-icing or anti-icing system selectionDiscrete “on” or “off”4
73. Computed center of gravityFull Range±5%(1 per 64 sec.)1% of full range
74. AC electrical bus statusDiscrete “power” or “off”4Each bus.
75. DC electrical bus statusDiscrete “power” or “off”4Each bus.
76 APU bleed valve positionDiscrete “open” or “closed”4
77. Hydraulic Pressure (each system)Full range±5%2100 psi
78. Loss of cabin pressureDiscrete “loss” or “normal”1
79. Computer failure (critical flight and engine control systems)Discrete “fail” or “normal”4
80. Heads-up display (when an information source is installed)Discrete(s) “on” or “off”4
81. Para-visual display (when an information source is installed)Discrete(s) “on” or “off”
82. Cockpit trim control input position—pitchFull Range±5%10.2% of full rangeWhere mechanical means for control inputs are not available, cockpit display trim positions should be recorded.
83. Cockpit trim control input position—rollFull Range±5%10.7% of full rangeWhere mechanical means for control inputs are not available, cockpit display trim position should be recorded.
84. Cockpit trim control input position—yawFull range±5%10.3% of full rangeWhere mechanical means for control input are not available, cockpit display trim positions should be recorded.
85. Trailing edge flap and cockpit flap control positionFull Range±5%20.5% of full rangeTrailing edge flaps and cockpit flap control position may each be sampled alternately at 4 second intervals to provide a sample each 0.5 second.
86. Leading edge flap and cockpit flap control positionFull Range or Discrete±5%10.5% of full range
87. Ground spoiler position and speed brake selectionFull range or discrete±5%0.50.3% of full range
88. All cockpit flight control input forces (control wheel, control column, rudder pedal)18 19Full range
Control wheel ±70 lbs
Control column ±85 lbs
Rudder pedal ±165 lbs
±5%10.3% of full rangeFor fly-by-wire flight control systems, where flight control surface position is a function of the displacement of the control input device only, it is not necessary to record this parameter. For airplanes that have a flight control break away capability that allows either pilot to operate the control independently, record both control force inputs. The control force inputs may be sampled alternately once per 2 seconds to produce the sampling interval of 1.
89. Yaw damper statusDiscrete (on/off)0.5
90. Yaw damper commandFull rangeAs installed0.51% of full range
91. Standby rudder valve statusDiscrete0.5

1For A300 B2/B4 airplanes, resolution = 6 seconds.

2For A330/A340 series airplanes, resolution = 0.703°.

3For A318/A319/A320/A321 series airplanes, resolution = 0.275% (0.088°>0.064°).

   For A330/A340 series airplanes, resolution = 2.20%(0.703°>0.064°).

4For A318/A319/A320/A321 series airplanes, resolution = 0.22% (0.088°>0.080°).

   For A330/A340 series airplanes, resolution = 1.76% (0.703°>0.080°).

5For A330/A340 series airplanes, resolution = 1.18% (0.703° >0.120°).

   For A330/A340 series airplanes, seconds per sampling interval = 1.

6For A330/A340 series airplanes, resolution = 0.783% (0.352°>0.090°).

7For A330/A340 series airplanes, aileron resolution = 0.704% (0.352°>0.100°). For A330/A340 series airplanes, spoiler resolution = 1.406% (0.703°>0.100°).

8For A330/A340 series airplanes, resolution = 0.30% (0.176°>0.12°).

   For A330/A340 series airplanes, seconds per sampling interval = 1.

9For B-717 series airplanes, resolution = .005g. For Dassault F900C/F900EX airplanes, resolution = .007g.

10For A330/A340 series airplanes, resolution = 1.05% (0.250°>0.120°).

11For A330/A340 series airplanes, resolution = 1.05% (0.250°>0.120°). For A300 B2/B4 series airplanes, resolution = 0.92% (0.230°>0.125°).

12For A330/A340 series airplanes, spoiler resolution = 1.406% (0.703°>0.100°).

13For A330/A340 series airplanes, resolution = 0.5°C.

14For Dassault F900C/F900EX airplanes, Radio altitude resolution = 1.25 ft.

15For A330/A340 series airplanes, resolution = 0.352 degrees.

16For A318/A319/A320/A321 series airplanes, resolution = 4.32%. For A330/A340 series airplanes, resolution is 3.27% of full range for throttle lever angle (TLA); for reverse thrust, reverse throttle lever angle (RLA) resolution is nonlinear over the active reverse thrust range, which is 51.54 degrees to 96.14 degrees. The resolved element is 2.8 degrees uniformly over the entire active reverse thrust range, or 2.9% of the full range value of 96.14 degrees.

17For A318/A319/A320/A321 series airplanes, with IAE engines, resolution = 2.58%.

18For all aircraft manufactured on or after December 6, 2010, the seconds per sampling interval is 0.125. Each input must be recorded at this rate. Alternately sampling inputs (interleaving) to meet this sampling interval is prohibited.

19For 737 model airplanes manufactured between August 19, 2000 and April 6, 2010: the seconds per sampling interval is 0.5 per control input; the remarks regarding the sampling rate do not apply; a single control wheel force transducer installed on the left cable control is acceptable provided the left and right control wheel positions also are recorded.

[Doc. No. 28109, 62 FR 38382, July 17, 1997; 62 FR 48135, Sept. 12, 1997, as amended by Amdt. 121-271, 64 FR 46120, Aug. 24, 1999; Amdt. 121-278, 65 FR 51745, Aug. 24, 2000; 65 FR 81733, Dec. 27, 2000; Amdt. 121-292, 67 FR 54323, Aug. 21, 2002; Amdt. 121-300, 68 FR 42936, July 18, 2003; 68 FR 50069, Aug. 20, 2003; 68 FR 53877, Sept. 15, 2003; 70 FR 41134, July 18, 2005; Amdt. 125-54, 73 FR 12566, Mar. 7, 2008; Amdt. 121-338, 73 FR 12566, Mar. 7, 2008; Amdt. 121-342, 73 FR 73179, Dec. 2, 2008; Amdt. 121-349, 75 FR 17046, Apr. 5, 2010; Amdt. 121-347, 75 FR 7356, Feb. 19, 2010; Amdt. 121-364, 78 FR 39971, July 3, 2013; Docket FAA-2017-0733, Amdt. 121-379, 82 FR 34398, July 25, 2017]

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