Code of Federal Regulations - Title 14

Federal Aviation Administration, DOT

Pt. 60, App. A

the horizontal axis and amplitude on the
vertical axis. The airplane data and flight
simulator data should be presented in the
same format with the same scaling. The al-
gorithms used for generating the flight simu-
lator data should be the same as those used
for the airplane data. If they are not the
same then the algorithms used for the flight
simulator data should be proven to be suffi-
ciently comparable. As a minimum, the re-
sults along the dominant axes should be pre-
sented and a rationale for not presenting the
other axes should be provided.

(2) Interpretation of results. The overall

trend of the PSD plot should be considered
while focusing on the dominant frequencies.
Less emphasis should be placed on the dif-
ferences at the high frequency and low am-
plitude portions of the PSD plot. During the
analysis, certain structural components of
the flight simulator have resonant fre-
quencies that are filtered and may not ap-
pear in the PSD plot. If filtering is required,
the notch filter bandwidth should be limited
to 1 Hz to ensure that the buffet feel is not
adversely affected. In addition, a rationale
should be provided to explain that the char-
acteristic motion vibration is not being ad-
versely affected by the filtering. The ampli-
tude should match airplane data as described
below. However, if the PSD plot was altered
for subjective reasons, a rationale should be
provided to justify the change. If the plot is
on a logarithmic scale, it may be difficult to
interpret the amplitude of the buffet in
terms of acceleration. For example, a 1

¥3

g-rms

/Hz would describe a heavy buffet and

may be seen in the deep stall regime. Alter-
natively, a 1

¥6

g-rms

/Hz buffet is almost

not perceivable; but may represent a flap
buffet at low speed. The previous two exam-
ples differ in magnitude by 1000. On a PSD
plot this represents three decades (one dec-
ade is a change in order of magnitude of 10;
and two decades is a change in order of mag-
nitude of 100).

OTE

: In the example, ‘‘g-rms

is the math-

ematical expression for ‘‘g’s root mean
squared.’’

7. S

OUND

YSTEM

a. General. The total sound environment in

the airplane is very complex, and changes
with atmospheric conditions, airplane con-
figuration, airspeed, altitude, and power set-
tings. Flight deck sounds are an important
component of the flight deck operational en-
vironment and provide valuable information
to the flight crew. These aural cues can ei-
ther assist the crew (as an indication of an
abnormal situation), or hinder the crew (as a
distraction or nuisance). For effective train-
ing, the flight simulator should provide
flight deck sounds that are perceptible to the
pilot during normal and abnormal oper-
ations, and comparable to those of the air-

plane. The flight simulator operator should
carefully evaluate background noises in the
location where the device will be installed.
To demonstrate compliance with the sound
requirements, the objective or validation
tests in this attachment were selected to
provide a representative sample of normal
static conditions typically experienced by a
pilot.

b. Alternate propulsion. For FFS with

multiple propulsion configurations, any con-
dition listed in Table A2A of this attachment
should be presented for evaluation as part of
the QTG if identified by the airplane manu-
facturer or other data supplier as signifi-
cantly different due to a change in propul-
sion system (engine or propeller).

c. Data and Data Collection System.
(1) Information provided to the flight simu-

lator manufacturer should be presented in
the format suggested by the International
Air Transport Association (IATA) ‘‘Flight
Simulator Design and Performance Data Re-
quirements,’’ as amended. This information
should contain calibration and frequency re-
sponse data.

(2) The system used to perform the tests

listed in Table A2A should comply with the
following standards:

(a) The specifications for octave, half oc-

tave, and third octave band filter sets may
be found in American National Standards In-
stitute (ANSI) S1.11–1986;

(b) Measurement microphones should be

type WS2 or better, as described in Inter-
national Electrotechnical Commission (IEC)
1094–4–1995.

(3) Headsets. If headsets are used during

normal operation of the airplane they should
also be used during the flight simulator eval-
uation.

(4) Playback equipment. Playback equip-

ment and recordings of the QTG conditions
should be provided during initial evalua-
tions.

(5) Background noise.
(a) Background noise is the noise in the

flight simulator that is not associated with
the airplane, but is caused by the flight sim-
ulator’s cooling and hydraulic systems and
extraneous noise from other locations in the
building. Background noise can seriously im-
pact the correct simulation of airplane
sounds and should be kept below the airplane
sounds. In some cases, the sound level of the
simulation can be increased to compensate
for the background noise. However, this ap-
proach is limited by the specified tolerances
and by the subjective acceptability of the
sound environment to the evaluation pilot.

(b) The acceptability of the background

noise levels is dependent upon the normal
sound levels in the airplane being rep-
resented. Background noise levels that fall
below the lines defined by the following
points, may be acceptable:

(i) 70 dB @ 50 Hz;

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