Federal Aviation Administration, DOT

Pt. 36, App. F

noisiest continuous state at the maximum
landing weight in normal operation.

APPENDIX
NOISE

Section B36.8 Noise Certification Test
Procedures
(a) All test procedures must be approved by
the FAA.
(b) The test procedures and noise measurements must be conducted and processed in
an approved manner to yield the noise evaluation metric EPNL, in units of EPNdB, as
described in appendix A of this part.
(c) Acoustic data must be adjusted to the
reference conditions specified in this appendix using the methods described in appendix
A of this part. Adjustments for speed and
thrust must be made as described in section
A36.9 of this part.
(d) If the airplane-s weight during the test
is different from the weight at which noise
certification is requested, the required EPNL
adjustment may not exceed 2 EPNdB for
each takeoff and 1 EPNdB for each approach.
Data approved by the FAA must be used to
determine the variation of EPNL with
weight for both takeoff and approach test
conditions. The necessary EPNL adjustment
for variations in approach flight path from
the reference flight path must not exceed 2
EPNdB.
(e) For approach, a steady glide path angle
of 3Section Section0.5Section is acceptable.
(f) If equivalent test procedures different
from the reference procedures are used, the
test procedures and all methods for adjusting
the results to the reference procedures must
be approved by the FAA. The adjustments
may not exceed 16 EPNdB on takeoff and 8
EPNdB on approach. If the adjustment is
more than 8 EPNdB on takeoff, or more than
4 EPNdB on approach, the resulting numbers
must be more than 2 EPNdB below the limit
noise levels specified in section B36.5.
(g) During takeoff, lateral, and approach
tests, the airplane variation in instantaneous indicated airspeed must be maintained
within Section3% of the average airspeed between
the 10 dB-down points. This airspeed is determined by the pilot-s airspeed indicator. However, if the instantaneous indicated airspeed
exceeds Section3 kt (Section5.5 km/h) of the average airspeed over the 10 dB-down points, and is determined by the FAA representative on the
flight deck to be due to atmospheric turbulence, then the flight so affected must be rejected for noise certification purposes.
NOTE: Guidance material on the use of
equivalent procedures is provided in the current advisory circular for this part.
spaschal on DSK3GDR082PROD with CFR

APPENDIXES C-E TO PART 36 [RESERVED]

[Amdt. 36-54, 67 FR 45235, July 8, 2002; Amdt.
36-24, 67 FR 63196, Oct. 10, 2002; 68 FR 1512,
Jan. 10, 2003; Amdt. 36-26, 70 FR 38749, July 5,
2005; FAA Doc. No. FAA-2015-3782, Amdt. No.
36-31, 82 FR 46131, Oct. 4, 2017]]

F TO PART 36 - FLYOVER
REQUIREMENTS FOR PROPELLER-DRIVEN
SMALL AIRPLANE
AND PROPELLER-DRIVEN, COMMUTER
CATEGORY AIRPLANE CERTIFICATION
TESTS PRIOR TO DECEMBER 22, 1988
PART A - GENERAL

Sec.
F36.1 Scope.
PART B - NOISE MEASUREMENT

F36.101 General test conditions.
F36.103 Acoustical measurement system.
F36.105 Sensing, recording, and reproducing
equipment.
F36.107 Noise measurement procedures.
F36.109 Data recording, reporting, and approval.
F36.111 Flight procedures.
PART C - DATA CORRECTION

F36.201 Correction of data.
F36.203 Validity of results.
PART D - NOISE LIMITS

F36.301 Aircraft noise limits.
PART A - GENERAL

Section F36.1 Scope. This appendix prescribes noise level limits and procedures for
measuring and correcting noise data for the
propeller driven small airplanes specified in
SectionSection 36.1 and 36.501(b).
PART B - NOISE MEASUREMENT

Sec. F36.101 General test conditions.
(a) The test area must be relatively flat
terrain having no excessive sound absorption
characteristics such as those caused by
thick, matted, or tall grass, by shrubs, or by
wooded areas. No obstructions which significantly influence the sound field from the airplane may exist within a conical space above
the measurement position, the cone being
defined by an axis normal to the ground and
by a half-angle 75 degrees from this axis.
(b) The tests must be carried out under the
following conditions:
(1) There may be no precipitation.
(2) Relative humidity may not be higher
than 90 percent or lower than 30 percent.
(3) Ambient temperature may not be above
86 degrees F. or below 41 degrees F. at 33-
above ground. If the measurement site is
within 1 n.m. of an airport thermometer the
airport reported temperature may be used.
(4) Reported wind may not be above 10
knots at 33- above ground. If wind velocities
of more than 4 knots are reported, the flight
direction must be aligned to within Section15 degrees of wind direction and flights with tail

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