Pt. 36, App. A

(1) The term 0.01[a(i) Section a(i)0]QK is the adjustment for the effect of the change in
sound attenuation coefficient, and a(i) and
a(i)0 are the coefficients for the test and reference atmospheric conditions respectively,
determined under section A36.7 of this appendix;
(2) The term 0.01a(i)0(QK Section QrKr) is the adjustment for the effect of the change in the
noise path length on the sound attenuation;
(3) The term 20 log(QK/QrKr) is the adjustment for the effect of the change in the noise
path length due to the inverse square law;
(4) QK and QrKr are measured in meters and
a(i) and a(i)0 are expressed in dB/100 m.
A36.9.3.2.1.1 PNLT Correction.
(a) Convert the corrected values, SPL(i)r,
to PNLTr;
(b) Calculate the correction term D1 using
the following equation:
D1 = PNLTr Section PNLTM
A36.9.3.2.1.2 Add D1 arithmetically to the
EPNL calculated from the measured data.
A36.9.3.2.2 If, during a test flight, several
peak values of PNLT that are within 2 dB of
PNLTM are observed, the procedure defined
in section A36.9.3.2.1 must be applied at each
peak, and the adjustment term, calculated
according to section A36.9.3.2.1, must be
added to each peak to give corresponding adjusted peak values of PNLT. If these peak
values exceed the value at the moment of
PNLTM, the maximum value of such exceedance must be added as a further adjustment
to the EPNL calculated from the measured
data.
A36.9.3.3 Adjustments to duration correction.

A36.9.3.3.1 Whenever the measured flight
paths and/or the ground velocities of the test
conditions differ from the reference flight
paths and/or the ground velocities of the reference conditions, duration adjustments
must be applied to the EPNL values calculated from the measured data. The adjustments must be calculated as described below.
A36.9.3.3.2 For the flight path shown in Figure A36-6, the adjustment term is calculated
as follows:

A36.9.3.4.2 Calculate adjustment term D3 by
subtracting the EPNL value corresponding

to the parameter Section from the EPNL value corresponding to the parameter Sectionr. Add D3

D2 = Section7.5 log(QK/QrKr) + 10 log(V/Vr)
(a) Add D2 arithmetically to the EPNL calculated from the measured data.
A36.9.3.4 Source noise adjustments.
A36.9.3.4.1 To account for differences between the parameters affecting engine noise
as measured in the certification flight tests,
and those calculated or specified in the reference conditions, the source noise adjustment must be calculated and applied. The
adjustment is determined from the manufacturer-s data approved by the FAA. Typical
data used for this adjustment are illustrated
in Figure A36-8 that shows a curve of EPNL
versus the engine control parameter Section, with
the EPNL data being corrected to all the
other relevant reference conditions (airplane
mass, speed and altitude, air temperature)
and for the difference in noise between the
test engine and the average engine (as defined in section B36.7(b)(7)). A sufficient
number of data points over a range of values
of Sectionr is required to calculate the source noise
adjustments for lateral, flyover and approach noise measurements.

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