773 

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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