772 

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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Federal Aviation Administration, DOT 

§ 36.101 

(a) 

General requirements. Except as 

otherwise provided, for helicopters cov-
ered by this section, the acoustical 
change approval requirements are as 
follows: 

(1) In showing compliance with the 

requirements of appendix H of this 
part, noise levels must be measured, 
evaluated, and calculated in accord-
ance with the applicable procedures 
and conditions prescribed in parts B 
and C of appendix H of this part. For 
helicopters having a maximum certifi-
cated takeoff weight of not more than 
7,000 pounds that alternatively dem-
onstrate compliance under appendix J 
of this part, the flyover noise level pre-
scribed in appendix J of this part must 
be measured, evaluated, and calculated 
in accordance with the applicable pro-
cedures and conditions prescribed in 
parts B and C of appendix J of this 
part. 

(2) Compliance with the noise limits 

prescribed in section H36.305 of appen-
dix H of this part must be shown in ac-
cordance with the applicable provisions 
of part D of appendix H of this part. 
For those helicopters that demonstrate 
compliance with the requirements of 
appendix J of this part, compliance 
with the noise levels prescribed in sec-
tion J36.305 of appendix J of this part 
must be shown in accordance with the 
applicable provisions of part D of ap-
pendix J of this part. 

(b) 

Stage 1 helicopters. Except as pro-

vided in § 36.805(c), for each Stage 1 hel-
icopter prior to a change in type de-
sign, the helicopter noise levels may 
not, after a change in type design, ex-
ceed the noise levels specified in sec-
tion H36.305(a)(1) of appendix H of this 
part where the demonstration of com-
pliance is under appendix H of this 
part. The tradeoff provisions under sec-
tion H36.305(b) of appendix H of this 
part may not be used to increase any 
Stage 1 noise level beyond these limits. 
If an applicant chooses to demonstrate 
compliance under appendix J of this 
part, for each Stage 1 helicopter prior 
to a change in type design, the heli-
copter noise levels may not, after a 
change in type design, exceed the Stage 
2 noise levels specified in section 
J36.305(a) of appendix J of this part. 

(c) 

Stage 2 helicopters. For each heli-

copter that is Stage 2 prior to a change 

in type design, after a change in type 
design the helicopter must either: 

(1) Remain a Stage 2 helicopter; or 
(2) Comply with Stage 3 requirements 

and remain a Stage 3 helicopter there-
after. 

(d) 

Stage 3 helicopters. For a heli-

copter that is a Stage 3 helicopter prior 
to a change in type design, the heli-
copter must remain a Stage 3 heli-
copter after a change in type design. 

[Doc. No. 26910, 57 FR 42854, Sept. 16, 1992, as 
amended by Amdt. 36–25, 69 FR 31234, June 2, 
2004; Amdt. 36–30, 79 FR 12044, Mar. 4, 2014] 

§ 36.13

Acoustical change: Tiltrotor 

aircraft. 

The following requirements apply to 

tiltrotors in any category for which an 
acoustical change approval is applied 
for under § 21.93(b) of this chapter on or 
after March 11, 2013: 

(a) In showing compliance with Ap-

pendix K of this part, noise levels must 
be measured, evaluated, and calculated 
in accordance with the applicable pro-
cedures and conditions prescribed in 
Appendix K of this part. 

(b) Compliance with the noise limits 

prescribed in section K4 (Noise Limits) 
of Appendix K of this part must be 
shown in accordance with the applica-
ble provisions of sections K2 (Noise 
Evaluation Measure), K3 (Noise Meas-
urement Reference Points), K6 (Noise 
Certification Reference Procedures), 
and K7 (Test Procedures) of Appendix K 
of this part. 

(c) After a change in type design, 

tiltrotor noise levels may not exceed 
the limits specified in § 36.1103. 

[Amdt. 36–29, 78 FR 1139, Jan. 8, 2013] 

Subpart B—Transport Category 

Large Airplanes and Jet Airplanes 

§ 36.101

Noise measurement and eval-

uation. 

For transport category large air-

planes and jet airplanes, the noise gen-
erated by the airplane must be meas-
ured and evaluated under appendix A of 
this part or under an approved equiva-
lent procedure. 

[Amdt. 36–54, 67 FR 45212, July 8, 2002] 

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