Federal Aviation Administration, DOT

Pt. 36, App. A

spaschal on DSK3GDR082PROD with CFR

(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 duration, the effects of airspeed on component
noise sources must be accounted for as follows: for conventional airplane configurations, when differences between test and reference airspeeds exceed 15 knots (28 km/h)
true airspeed, test data and/or analysis approved by the FAA must be used to quantify
the effects of the airspeed adjustment on resulting certification noise levels.
A36.9.1.2 The  - integrated -  method of adjustment, described in section A36.9.4, must
be used on takeoff or approach under the following 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, together with the associated airplane speed
relative to the ground, and the associated
engine control parameter(s) used for determining the noise emission of the airplane.
A36.9.2.1 Takeoff Profile.
NOTE: 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) cutback is used, it is started at point D and
completed at point E. From here, the airplane begins a second climb at a constant
angle up to point F, the end of the noise certification takeoff flight path.
(b) Position K1 is the takeoff noise measuring station and AK1 is the distance from
start of roll to the flyover measuring point.
Position K2 is the lateral noise measuring
station, which is located on a line parallel
to, and the specified distance from, the runway 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.
NOTE: Figure A36-5 illustrates a typical approach profile.
(a) The airplane begins its noise certification 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 K3 is the approach noise measuring station and K3O 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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