797 

Federal Aviation Administration, DOT 

Pt. 36, App. A 

(c) Source noise emitted by the engine as 

affected by the differences between test and 
reference engine operating conditions 

(d) Airplane/engine source noise as affected 

by differences between test and reference 
airspeeds. In addition to the effect on dura-
tion, the effects of airspeed on component 
noise sources must be accounted for as fol-
lows: for conventional airplane configura-
tions, when differences between test and ref-
erence airspeeds exceed 15 knots (28 km/h) 
true airspeed, test data and/or analysis ap-
proved by the FAA must be used to quantify 
the effects of the airspeed adjustment on re-
sulting certification noise levels. 

A36.9.1.2 The ‘‘integrated’’ method of ad-

justment, described in section A36.9.4, must 
be used on takeoff or approach under the fol-
lowing conditions: 

(a) When the amount of the adjustment 

(using the ‘‘simplified’’ method) is greater 
than 8 dB on flyover, or 4 dB on approach; or 

(b) When the resulting final EPNL value on 

flyover or approach (using the simplified 
method) is within 1 dB of the limiting noise 
levels as prescribed in section B36.5 of this 
part. 

A36.9.2 

Flight profiles. 

As described below, flight profiles for both 

test and reference conditions are defined by 
their geometry relative to the ground, to-
gether with the associated airplane speed 
relative to the ground, and the associated 
engine control parameter(s) used for deter-
mining the noise emission of the airplane. 

A36.9.2.1 

Takeoff Profile. 

N

OTE

: Figure A36–4 illustrates a typical 

takeoff profile. 

(a) The airplane begins the takeoff roll at 

point A, lifts off at point B and begins its 
first climb at a constant angle at point C. 
Where thrust or power (as appropriate) cut- 
back is used, it is started at point D and 
completed at point E. From here, the air-
plane begins a second climb at a constant 
angle up to point F, the end of the noise cer-
tification takeoff flight path. 

(b) Position K

1

is the takeoff noise meas-

uring station and AK

1

is the distance from 

start of roll to the flyover measuring point. 
Position K

2

is the lateral noise measuring 

station, which is located on a line parallel 
to, and the specified distance from, the run-
way center line where the noise level during 
takeoff is greatest. 

(c) The distance AF is the distance over 

which the airplane position is measured and 
synchronized with the noise measurements, 
as required by section A36.2.3.2 of this part. 

A36.9.2.2 

Approach Profile. 

N

OTE

: Figure A36–5 illustrates a typical ap-

proach profile. 

(a) The airplane begins its noise certifi-

cation approach flight path at point G and 
touches down on the runway at point J, at a 
distance OJ from the runway threshold. 

(b) Position K

3

is the approach noise meas-

uring station and K

3

O is the distance from 

the approach noise measurement point to 
the runway threshold. 

(c) The distance GI is the distance over 

which the airplane position is measured and 
synchronized with the noise measurements, 
as required by section A36.2.3.2 of this part. 

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