Federal Aviation Administration, DOT

Section 36.7

Method for Free-Field Calibration of
Laboratory Standard Microphones by
the Reciprocity Technique, edition 1.0,
1995 (IEC 61094-3) IBR approved for appendix A to part 36.
(6) Publication No. 61094-4, Measurement Microphones - Part 4: Specifications for Working Standard Microphones, edition 1.0, 1995, (IEC 61094-4)
IBR approved for appendix A to part 36.
(7)
Publication
No.
61260,
Electroacoustics-Octave-Band
and
Fractional-Octave-Band Filters, edition 1.0, 1995, (IEC 61260), IBR approved
for appendix A to part 36.
(8)
Publication
No,
60942,
Electroacoustics-Sound
Calibrators,
edition 2.0, 1997, (IEC 60942) IBR approved for appendix A to part 36.
(d) Society of Automotive Engineers,
Inc. (SAE), 400 Commonwealth Drive,
Warrentown,
PA
15096,
http://
www.sae.org/pubs/.
(1) ARP 866A, Standard Values at Atmospheric Absorption as a Function of
Temperature and Humidity for use in
Evaluating Aircraft Flyover Noise,
March 15, 1975, IBR approved for appendix H to part 36.
(2) [Reserved]

spaschal on DSK3GDR082PROD with CFR

[Doc. No. FAA-2015-3782, Amdt. No. 36-31, 82
FR 46129, Oct. 4, 2017]

Section 36.7 Acoustical change: Transport
category large airplanes and jet airplanes.
(a) Applicability. This section applies
to all transport category large airplanes and jet airplanes for which an
acoustical change approval is applied
for under Section 21.93(b) of this chapter.
(b) General requirements. Except as
otherwise specifically provided, for
each airplane covered by this section,
the acoustical change approval requirements are as follows:
(1) In showing compliance, noise levels must be measured and evaluated in
accordance with the applicable procedures and conditions prescribed in Appendix A of this part.
(2) Compliance with the noise limits
prescribed in section B36.5 of appendix
B must be shown in accordance with
the applicable provisions of sections
B36.7 and B36.8 of appendix B of this
part.
(c) Stage 1 airplanes. For each Stage 1
airplane prior to the change in type de-

sign, in addition to the provisions of
paragraph (b) of this section, the following apply:
(1) If an airplane is a Stage 1 airplane
prior to the change in type design, it
may not, after the change in type design, exceed the noise levels created
prior to the change in type design. The
tradeoff provisions of section B36.6 of
appendix B of this part may not be
used to increase the Stage 1 noise levels, unless the aircraft qualifies as a
Stage 2 airplane.
(2) In addition, for an airplane for
which application is made after September 17, 1971 - 
(i) There may be no reduction in
power or thrust below the highest airworthiness approved power or thrust,
during the tests conducted before and
after the change in type design; and
(ii) During the flyover and lateral
noise tests conducted before the change
in type design, the quietest airworthiness approved configuration available
for the highest approved takeoff weight
must be used.
(d) Stage 2 airplanes. If an airplane is
a Stage 2 airplane prior to the change
in type design, the following apply, in
addition to the provisions of paragraph
(b) of this section:
(1) Airplanes with high bypass ratio jet
engines. For an airplane that has jet
engines with a bypass ratio of 2 or
more before a change in type design - 
(i) The airplane, after the change in
type design, may not exceed either (A)
each Stage 3 noise limit by more than
3 EPNdB, or (B) each Stage 2 noise
limit, whichever is lower:
(ii) The tradeoff provisions of section
B36.6 of appendix B of this part may be
used in determining compliance under
this paragraph with respect to the
Stage 2 noise limit or to the Stage 3
plus 3 EPNdB noise limits, as applicable; and
(iii) During the flyover and lateral
noise test conducted before the change
in type design, the quietest airworthiness approved configuration available
for the highest approved takeoff weight
must be used.
(2) Airplanes that do not have high bypass ratio jet engines. For an airplane
that does not have jet engines with a
bypass ratio of 2 or more before a
change in type design - 

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