954 

14 CFR Ch. I (1–1–14 Edition) 

Pt. 36, App. G 

(c) For airplanes for which application for 

a type certificate is made on or after Janu-
ary 1, 1975, the noise levels may not exceed 
the noise limit curve prescribed in paragraph 
(b) of this section, except that 80 dB(A) may 
not be exceeded. 

(d) For airplanes for which application is 

made for a standard airworthiness certificate 
or for a restricted category airworthiness 
certificate, and that have not had any flight 
time before January 1, 1980, the require-
ments of paragraph (c) of this section apply, 
regardless of date of application, to the 
original issuance of the certificate for that 
airplane. 

[Doc. No. 13243, 40 FR 1035, Jan. 6, 1975; 40 FR 
6347, Feb. 11, 1975, as amended by Amdt. 36– 
6, 41 FR 56064, Dec. 23, 1976; Amdt. 36-6, 42 FR 
4113, Jan. 24, 1977; Amdt. 36–9, 43 FR 8754, 
Mar. 2, 1978; Amdt. 36–13, 52 FR 1836, Jan. 15, 
1987; Amdt. 36–16, 53 FR 47400, Nov. 22, 1988] 

A

PPENDIX

G 

TO

P

ART

36—T

AKEOFF

 

N

OISE

R

EQUIREMENTS

FOR

P

RO

-

PELLER

-D

RIVEN

S

MALL

A

IRPLANE

 

AND

P

ROPELLER

-D

RIVEN

, C

OMMUTER

 

C

ATEGORY

A

IRPLANE

C

ERTIFICATION

 

T

ESTS ON OR

A

FTER

D

ECEMBER

22, 

1988 

PART A

—

GENERAL

 

Sec. 
G36.1 

Scope. 

PART B

—

NOISE MEASUREMENT

 

G36.101 

General Test Conditions. 

G36.103 

Acoustical measurement system. 

G36.105 

Sensing, recording, and reproducing 

equipment. 

G36.107 

Noise measurement procedures. 

G36.109 

Data recording, reporting, and ap-

proval. 

G36.111 

Flight procedures. 

PART C

—

DATA CORRECTIONS

 

G36.201 

Corrections to Test Results. 

G36.203 

Validity of results. 

PART D

—

NOISE LIMITS

 

G36.301 

Aircraft Noise Limits. 

PART A

—

GENERAL

 

Section G36.1 Scope. This appendix pre-

scribes limiting noise levels and procedures 
for measuring noise and adjusting these data 
to standard conditions, for propeller driven 
small airplanes and propeller-driven, com-
muter category airplanes specified in §§ 36.1 
and 36.501(c). 

PART B

—

NOISE MEASUREMENT

 

Sec. G36.101 General Test Conditions. 

(a) The test area must be relatively flat 

terrain having no excessive sound absorption 
characteristics such as those caused by 
thick, matted, or tall grass, by shrubs, or by 
wooded areas. No obstructions which signifi-
cantly influence the sound field from the air-
plane may exist within a conical space above 
the measurement position, the cone being 
defined by an axis normal to the ground and 
by a half-angle 75 degrees from the normal 
ground axis. 

(b) The tests must be carried out under the 

following conditions: 

(1) No precipitation; 
(2) Ambient air temperature between 36 

and 95 degrees F (2.2 and 35 degrees C); 

(3) Relative humidity between 20 percent 

and 95 percent, inclusively; 

(4) Wind speed may not exceed 10 knots (19 

km/h) and cross wind may not exceed 5 knots 
(9 km/h), using a 30-second average; 

(5) No temperature inversion or anomalous 

wind condition that would significantly alter 
the noise level of the airplane when the nose 
is recorded at the required measuring point, 
and 

(6) The meteorological measurements must 

be made between 4 ft. (1.2 m) and 33 ft. (10 m) 
above ground level. If the measurement site 
is within 1 n.m. of an airport meteorological 
station, measurements from that station 
may be used. 

(c) The flight test procedures, measuring 

equipment, and noise measurement proce-
dures must be approved by the FAA. 

(d) Sound pressure level data for noise 

evaluation purposes must be obtained with 
acoustical equipment that complies with 
section G36.103 of this appendix. 

Sec. G36.103 Acoustical Measurement System. 

The acoustical measurement system must 

consist of approved equipment with the fol-
lowing characteristics: (a) A microphone sys-
tem with frequency response compatible 
with measurement and analysis system accu-
racy as prescribed in section G36.105 of this 
appendix. 

(b) Tripods or similar microphone mount-

ings that minimize interference with the 
sound being measured. 

(c) Recording and reproducing equipment 

characteristics, frequency response, and dy-
namic range compatible with the response 
and accuracy requirements of section G36.105 
of this appendix. 

(d) Acoustic calibrators using sine wave or 

broadband noise of known sound pressure 
level. If broadband noise is used, the signal 
must be described in terms of its average and 
maximum root-mean-square (rms) value for 
non-overload signal level. 

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