Appendix E to Part 91—Airplane Flight Recorder Specifications

Parameters Range Installed system 1 minimum accuracy (to recovered data) Sampling interval (per second) Resolution 4 read out
Relative Time (From Recorded on Prior to Takeoff)8 hr minimum±0.125% per hour11 sec.
Indicated AirspeedVso to VD (KIAS)±5% or ±10 kts., whichever is greater. Resolution 2 kts. below 175 KIAS11% 3
Altitude−1,000 ft. to max cert. alt. of A/C±100 to ±700 ft. (see Table 1, TSO C51-a)125 to 150 ft.
Magnetic Heading360°±5°11°
Vertical Acceleration−3g to + 6g±0.2g in addition to ±0.3g maximum datum4 (or 1 per second where peaks, ref. to 1g are recorded)0.03g.
Longitudinal Acceleration±1.0g±1.5% max. range excluding datum error of ±5%20.01g.
Pitch Attitude100% of usable±2°10.8°
Roll Attitude±60° or 100% of usable range, whichever is greater±2°10.8°
Stabilizer Trim Position, orFull Range±3% unless higher uniquely required11% 3
Pitch Control Position 5
Engine Power, Each Engine:Full Range±3% unless higher uniquely required11% 3
Fan or N 1 Speed or EPR or Cockpit indications Used for Aircraft Certification ORMaximum Range±5%11% 3
Prop. speed and Torque (Sample Once/Sec as Close together as Practicable)1 (prop Speed)
1 (torque)		1% 3
1% 3
Altitude Rate 2 (need depends on altitude resolution)±8,000 fpm±10%. Resolution 250 fpm below 12,000 ft. indicated1250 fpm. below 12,000
Angle of Attack 2 (need depends on altitude resolution)−20° to 40° or 100% of usable range±2°10.8% 3
Radio Transmitter Keying (Discrete)On/Off1
TE Flaps (Discrete or Analog)Each discrete position (U, D, T/O, AAP) OR1
LE Flaps (Discrete or Analog)Analog 0-100% range±3%11% 3
Each discrete position (U, D, T/O, AAP) OR1
Thrust Reverser, Each Engine (Discrete)Analog 0-100% range±3°11% 3
Stowed or full reverse
Spoiler/Speedbrake (Discrete)Stowed or out1
Autopilot Engaged (Discrete)Engaged or Disengaged1

1 When data sources are aircraft instruments (except altimeters) of acceptable quality to fly the aircraft the recording system excluding these sensors (but including all other characteristics of the recording system) shall contribute no more than half of the values in this column.

2 If data from the altitude encoding altimeter (100 ft. resolution) is used, then either one of these parameters should also be recorded. If however, altitude is recorded at a minimum resolution of 25 feet, then these two parameters can be omitted.

3 Per cent of full range.

4 This column applies to aircraft manufactured after October 11, 1991.

5 For Pitch Control Position only, for all aircraft manufactured on or after April 6, 2012, the sampling interval (per second) is 8. Each input must be recorded at this rate. Alternately sampling inputs (interleaving) to meet this sampling interval is prohibited.

[Docket 18334, 54 FR 34327, Aug. 18, 1989, as amended by Amdt. 91-300, 73 FR 12565, Mar. 7, 2008; 73 FR 15280, Mar. 21, 2008; Amdt. 91-313, 75 FR 17046, Apr. 5, 2010; Amdt. 91-329, 78 FR 39971, July 3, 2013]