Federal Aviation Administration, DOT

Pt. 36, App. J

LAMAX and the integration interval (in seconds) for inclusion in the noise data submitted as part of the reporting requirements
under section J36.111(b) of this appendix.

spaschal on DSK3GDR082PROD with CFR

Section J36.111 Reporting Requirements.
(a) General. Data representing physical
measurements, and corrections to measured
data, including corrections to measurements
for equipment response deviations, must be
recorded in permanent form and appended to
the record. Each correction is subject to
FAA approval.
(b) Data reporting. After the completion of
the test the following data must be included
in the test report furnished to the FAA:
(1) Measured and corrected sound levels obtained with equipment conforming to the
standards prescribed in section J36.109 of this
appendix;
(2) The type of equipment used for measurement and analysis of all acoustic, aircraft
performance and flight path, and meteorological data;
(3) The atmospheric environmental data
required to demonstrate compliance with
this appendix, measured throughout the test
period;
(4) Conditions of local topography, ground
cover, or events which may interfere with
the sound recording;
(5) The following helicopter information:
(i) Type, model, and serial numbers, if any,
of helicopter, engine(s) and rotor(s);
(ii) Gross dimensions of helicopter, location of engines, rotors, type of antitorque
system, number of blades for each rotor, and
reference operating conditions for each engine and rotor;
(iii) Any modifications of non-standard
equipment likely to affect the noise characteristics of the helicopter;
(iv) Maximum takeoff weight for which
certification under this appendix is requested;
(v) Aircraft configuration, including landing gear positions;
(vi) VH or VNE (whichever is less) and the
adjusted reference airspeed;
(vii) Aircraft gross weight for each test
run;
(viii) Indicated and true airspeed for each
test run;
(ix) Ground speed, if measured, for each
run;
(x) Helicopter engine performance as determined from aircraft instruments and manufacturer-s data; and
(xi) Aircraft flight path above ground
level, referenced to the elevation of the noise
measurement station, in feet, determined by
an FAA-approved method which is independent of normal flight instrumentation,
such as radar tracking, theodolite triangulation, laser trajectography, or photoscaling
techniques; and

(6) Helicopter position and performance
data required to make the adjustments prescribed under section J36.205 of this appendix
and to demonstrate compliance with the performance and position restrictions prescribed under section J36.105 of this appendix
must be recorded at an FAA-approved sampling rate.
Section J36.113 [Reserved]
PART C - NOISE EVALUATION AND
CALCULATIONS UNDER Section 36.803
Section J36.201 Noise Evaluation in SEL.
The noise evaluation measure shall be the
sound exposure level (SEL) in units of dB(A)
as prescribed under section J36.109(b) of this
appendix. The SEL value for each flyover
may be directly determined by use of an integrating sound level meter. Specifications
for the integrating sound level meter and requirements governing the use of such instrumentation are prescribed under section
J36.109 of this appendix.
Section J36.203 Calculation of Noise Levels.
(a) To demonstrate compliance with the
noise level limits specified under section
J36.305 of this appendix, the SEL noise levels
from each valid flyover, corrected as necessary to reference conditions under section
J36.205
of
this
appendix,
must
be
arithmetically averaged to obtain a single
SEL dB(A) mean value for the flyover series.
No individual flyover run may be omitted
from the averaging process, unless otherwise
specified or approved by the FAA.
(b) The minimum sample size acceptable
for the helicopter flyover certification measurements is six. The number of samples must
be large enough to establish statistically a 90
percent confidence limit that does not exceed Section1.5 dB(A).
(c) All data used and calculations performed under this section, including the calculated 90 percent confidence limits, must be
documented and provided under the reporting requirements of section J36.111 of this
appendix.
Section J36.205 Detailed Data Correction
Procedures.
(a) When certification test conditions
measured under part B of this appendix differ
from the reference test conditions prescribed
under section J36.3 of this appendix, appropriate adjustments shall be made to the
measured noise data in accordance with the
methods set out in paragraphs (b) and (c) of
this section. At minimum, appropriate adjustments shall be made for off-reference altitude and for the difference between reference airspeed and adjusted reference airspeed.
(b) The adjustment for off-reference altitude may be approximated from:

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