257
Federal Aviation Administration, DOT
Pt. 121, App. B
Parameters Range
Accuracy sensor input to
DFDR readout
Sampling inter-
val (per second)
Resolution
4
readout
Thrust Reverser Position ........
Stowed, In Transit, and
Reverse (Discrete).
................................................
1 (per 4 sec-
onds per en-
gine).
Ground Spoiler Position/
Speed Brake Selection.
Full Range or Each Dis-
crete Position.
±
2% Unless Higher Accuracy
Uniquely Required.
1 ........................
0.2%
2
.
Marker Beacon Passage ........
Discrete ..........................
................................................
1 ........................
Autopilot Engagement ............
Discrete ..........................
................................................
1 ........................
Longitudinal Acceleration .......
±
1g ..................................
±
1.5% max range excluding
datum error of
±
5%.
4 ........................
0.01g.
Pilot Input and/or Surface Po-
sition—Primary Controls
(Pitch, Roll, Yaw)
3
.
Full Range ......................
±
2
°
Unless Higher Accuracy
Uniquely Required.
1 ........................
0.2%
2
.
Lateral Acceleration ................
±
1g ..................................
±
1.5% max range excluding
datum error of
±
5%.
4 ........................
0.01g.
Pitch Trim Position .................
Full Range ......................
±
3% Unless Higher Accuracy
Uniquely Required.
1 ........................
0.3%
2
.
Glideslope Deviation ..............
±
400 Microamps .............
±
3% .......................................
1 ........................
0.3%
2
.
Localizer Deviation .................
±
400 Microamps .............
±
3% .......................................
1 ........................
0.3%
2
.
AFCS Mode and Engagement
Status.
Discrete ..........................
................................................
1 ........................
Radio Altitude .........................
¥
20 ft to 2,500 ft ...........
±
2 Ft or
±
3% Whichever is
Greater Below 500 Ft and
±
5% Above 500 Ft.
1 ........................
1 ft + 5%
2
above 500
′
.
Master Warning ......................
Discrete ..........................
................................................
1 ........................
Main Gear Squat Switch Sta-
tus.
Discrete ..........................
................................................
1 ........................
Angle of Attack (if recorded di-
rectly)..
As installed .....................
As installed ............................
2 ........................
0.3%
2
Outside Air Temperature or
Total Air Temperature..
¥
50
°
C to + 90
°
C .........
±
2
°
c ......................................
0.5 .....................
0.3
°
c
Hydraulics, Each System Low
Pressure.
Discrete ..........................
................................................
0.5 .....................
or 0.5%
2
Groundspeed. .........................
As installed .....................
Most Accurate Systems In-
stalled (IMS Equipped Air-
craft Only).
1 ........................
0.2%
2
If additional recording capacity is available, recording of the following parameters is recommended. The parameters are listed in
order of significance:
Drift Angle ...............................
When available, As in-
stalled.
As installed ............................
4 ........................
Wind Speed and Direction .....
When available, As in-
stalled.
As installed ............................
4 ........................
Latitude and Longitude ...........
When available, As in-
stalled.
As installed ............................
4 ........................
Brake pressure/Brake pedal
position.
As installed .....................
As installed ............................
1 ........................
Additional engine parameters:
EPR .................................
As installed .....................
As installed ............................
1 (per engine). ..
N1 ....................................
As installed .....................
As installed ............................
1 (per engine). ..
N2 ....................................
As installed .....................
As installed ............................
1 (per engine). ..
EGT .................................
As installed .....................
As installed ............................
1 (per engine). ..
Throttle Lever Position ...........
As installed .....................
As installed ............................
1 (per engine). ..
Fuel Flow ................................
As installed .....................
As installed ............................
1 (per engine). ..
TCAS:
TA ....................................
As installed .....................
As installed ............................
1 ........................
RA ...................................
As installed .....................
As installed ............................
1 ........................
Sensitivity level (as se-
lected by crew).
As installed .....................
As installed ............................
2 ........................
GPWS (ground proximity
warning system).
Discrete ..........................
................................................
1 ........................
Landing gear or gear selector
position.
Discrete ..........................
................................................
0.25 (1 per 4
seconds).
DME 1 and 2 Distance ...........
0–200 NM; ......................
As installed ............................
0.25 ...................
1 mi.
Nav 1 and 2 Frequency Se-
lection.
Full range .......................
As installed ............................
0.25 ...................
1
When altitude rate is recorded. Altitude rate must have sufficient resolution and sampling to permit the derivation of altitude to
5 feet.
2
Per cent of full range.
3
For airplanes that can demonstrate the capability of deriving either the control input on control movement (one from the
other) for all modes of operation and flight regimes, the ‘‘or’’ applies. For airplanes with non-mechanical control systems (fly-by-
wire) the ‘‘and’’ applies. In airplanes with split surfaces, suitable combination of inputs is acceptable in lieu of recording each sur-
face separately.
4
This column applies to aircraft manufactured after October 11, 1991.
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