914
14 CFR Ch. I (1–1–14 Edition)
§ 36.11
(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.
(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, the helicopter must be
a Stage 2 helicopter 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]
§ 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
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