Appendix B to Part 135 - 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)25 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
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 positionFull range±3% unless higher uniquely required11% 3.
Or
Pitch control positionFull range±3% unless higher uniquely required11% 3.
Engine Power, Each Engine
Fan or N1 speed or EPR or cockpit indications used for aircraft certificationMaximum range±5%11% 3.
Or
Prop. speed and torque (sample once/sec as close together as practicable)1 (prop speed), 1 (torque)
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 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)1
Or
Analog 0-100% range±3°11% 3
LE flaps (discrete or analog)Each discrete position (U, D, T/O, AAP)1
Or
Analog 0-100% range±3°11% 3.
Thrust reverser, each engine (Discrete)Stowed or full reverse1
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 manufacturing after October 11, 1991.

[Doc. No. 25530, 53 FR 26152, July 11, 1988; 53 FR 30906, Aug. 16, 1988, as amended by Amdt. 135-69, 62 FR 38397, July 17, 1997]