771 

Federal Aviation Administration, DOT 

§ 36.7 

Laboratory Standard Microphones by 
the Reciprocity Technique, edition 1.0, 
1995 (IEC 61094–3) IBR approved for ap-
pendix A to part 36. 

(6) Publication No. 61094–4, Measure-

ment Microphones—Part 4: Specifica-
tions for Working Standard Micro-
phones, 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, edi-
tion 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 ap-
proved 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 At-

mospheric Absorption as a Function of 
Temperature and Humidity for use in 
Evaluating Aircraft Flyover Noise, 
March 15, 1975, IBR approved for appen-
dix H to part 36. 

(2) [Reserved] 

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

§ 36.7

Acoustical change: Transport 

category large airplanes and jet air-
planes. 

(a) 

Applicability.  This section applies 

to all transport category large air-
planes and jet airplanes for which an 
acoustical change approval is applied 
for under § 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 require-
ments are as follows: 

(1) In showing compliance, noise lev-

els must be measured and evaluated in 
accordance with the applicable proce-
dures and conditions prescribed in Ap-
pendix 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 fol-
lowing 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 de-
sign, 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 lev-
els, unless the aircraft qualifies as a 
Stage 2 airplane. 

(2) In addition, for an airplane for 

which application is made after Sep-
tember 17, 1971— 

(i) There may be no reduction in 

power or thrust below the highest air-
worthiness 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 airworthi-
ness 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 applica-
ble; and 

(iii) During the flyover and lateral 

noise test conducted before the change 
in type design, the quietest airworthi-
ness approved configuration available 
for the highest approved takeoff weight 
must be used. 

(2) 

Airplanes that do not have high by-

pass 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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14 CFR Ch. I (1–1–24 Edition) 

§ 36.9 

(i) The airplane may not be a Stage 1 

airplane after the change in type de-
sign; and 

(ii) During the flyover and lateral 

noise tests conducted before the change 
in type design, the quietest airworthi-
ness approved configuration available 
for the highest approved takeoff weight 
must be used. 

(e) 

Stage 3 airplanes. If an airplane is 

a Stage 3 airplane prior to the change 
in type design, the following apply, in 
addition to the provisions of paragraph 
(b) of this section: 

(1) If compliance with Stage 3 noise 

levels is not required before the change 
in type design, the airplane must— 

(i) Be a Stage 2 airplane after the 

change in type design and compliance 
must be shown under the provisions of 
paragraph (d)(1) or (d)(2) of this sec-
tion, as appropriate; or 

(ii) Remain a Stage 3 airplane after 

the change in type design. Compliance 
must be shown under the provisions of 
paragraph (e)(2) of this section. 

(2) If compliance with Stage 3 noise 

levels is required before the change in 
type design, the airplane must be a 
Stage 3 airplane after the change in 
type design. 

(3) Applications on or after [August 

14, 1989.] The airplane must remain a 
Stage 3 airplane after the change in 
type design. 

(4) If an airplane is a Stage 3 airplane 

prior to a change in type design, and 
becomes a Stage 4 after the change in 
type design, the airplane must remain 
a Stage 4 airplane. 

(5) If an airplane is a Stage 3 airplane 

prior to a change in type design, and 
becomes a Stage 5 airplane after the 
change in type design, the airplane 
must remain a Stage 5 airplane. 

(f) 

Stage 4 airplanes. (1) If an airplane 

is a Stage 4 airplane prior to a change 
in type design, the airplane must re-
main a Stage 4 airplane after the 
change in type design. 

(2) If an airplane is a Stage 4 airplane 

prior to a change in type design, and 
becomes a Stage 5 airplane after the 
change in type design, the airplane 
must remain a Stage 5 airplane. 

(g) 

Stage 5 airplanes. If an airplane is 

a Stage 5 airplane prior to a change in 
type design, the airplane must remain 

a Stage 5 airplane after the change in 
type design. 

[Amdt. 36–7, 42 FR 12371, Mar. 3, 1977; Amdt. 
36–8, 43 FR 8730, Mar. 2, 1978; Amdt. 36–10, 43 
FR 28420, June 29, 1978; Amdt. 36–12, 46 FR 
33464, June 29, 1981; Amdt. 36–15, 53 FR 16366, 
May 6, 1988; 53 FR 18950, May 25, 1988; Amdt. 
36–17, 54 FR 21042, May 15, 1989; Amdt. 36–54, 
67 FR 45212, July 8, 2002; Amdt. 36–26, 70 FR 
38749, July 5, 2005; FAA Doc. No. FAA–2015– 
3782, Amdt. No. 36–31, 82 FR 46130, Oct. 4, 
2017] 

§ 36.9

Acoustical change: Propeller- 

driven small airplanes and pro-
peller-driven commuter category 
airplanes. 

For propeller-driven small airplanes 

in the primary, normal, utility, acro-
batic, transport, and restricted cat-
egories and for propeller-driven, com-
muter category airplanes for which an 
acoustical change approval is applied 
for under § 21.93(b) of this chapter after 
January 1, 1975, the following apply: 

(a) If the airplane was type certifi-

cated under this part prior to a change 
in type design, it may not subsequently 
exceed the noise limits specified in 
§ 36.501 of this part. 

(b) If the airplane was not type cer-

tificated under this part prior to a 
change in type design, it may not ex-
ceed the higher of the two following 
values: 

(1) The noise limit specified in § 36.501 

of this part, or 

(2) The noise level created prior to 

the change in type design, measured 
and corrected as prescribed in § 36.501 of 
this part. 

[Amdt. 36–16, 53 FR 47400, Nov. 22, 1988; 53 FR 
50157, Dec. 13, 1988; Amdt. 36–19, 57 FR 41369, 
Sept. 9, 1992] 

§ 36.11

Acoustical change: Helicopters. 

This section applies to all helicopters 

in the primary, normal, transport, and 
restricted categories for which an 
acoustical change approval is applied 
for under § 21.93(b) of this chapter on or 
after March 6, 1986. Compliance with 
the requirements of this section must 
be demonstrated under appendix H of 
this part, or, for helicopters having a 
maximum certificated takeoff weight 
of not more than 7,000 pounds, compli-
ance with this section may be dem-
onstrated under appendix J of this 
part. 

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