809 

Federal Aviation Administration, DOT 

Pt. 36, App. F 

noisiest continuous state at the maximum 
landing weight in normal operation. 

Section B36.8 Noise Certification Test 

Procedures 

(a) All test procedures must be approved by 

the FAA. 

(b) The test procedures and noise measure-

ments must be conducted and processed in 
an approved manner to yield the noise eval-
uation metric EPNL, in units of EPNdB, as 
described in appendix A of this part. 

(c) Acoustic data must be adjusted to the 

reference conditions specified in this appen-
dix using the methods described in appendix 
A of this part. Adjustments for speed and 
thrust must be made as described in section 
A36.9 of this part. 

(d) If the airplane’s weight during the test 

is different from the weight at which noise 
certification is requested, the required EPNL 
adjustment may not exceed 2 EPNdB for 
each takeoff and 1 EPNdB for each approach. 
Data approved by the FAA must be used to 
determine the variation of EPNL with 
weight for both takeoff and approach test 
conditions. The necessary EPNL adjustment 
for variations in approach flight path from 
the reference flight path must not exceed 2 
EPNdB. 

(e) For approach, a steady glide path angle 

of 3

° ±

0.5

° 

is acceptable. 

(f) If equivalent test procedures different 

from the reference procedures are used, the 
test procedures and all methods for adjusting 
the results to the reference procedures must 
be approved by the FAA. The adjustments 
may not exceed 16 EPNdB on takeoff and 8 
EPNdB on approach. If the adjustment is 
more than 8 EPNdB on takeoff, or more than 
4 EPNdB on approach, the resulting numbers 
must be more than 2 EPNdB below the limit 
noise levels specified in section B36.5. 

(g) During takeoff, lateral, and approach 

tests, the airplane variation in instanta-
neous indicated airspeed must be maintained 
within 

±

3% of the average airspeed between 

the 10 dB-down points. This airspeed is deter-
mined by the pilot’s airspeed indicator. How-
ever, if the instantaneous indicated airspeed 
exceeds 

±

3 kt (

±

5.5 km/h) of the average air-

speed over the 10 dB-down points, and is de-
termined by the FAA representative on the 
flight deck to be due to atmospheric turbu-
lence, then the flight so affected must be re-
jected for noise certification purposes. 

N

OTE

: Guidance material on the use of 

equivalent procedures is provided in the cur-
rent advisory circular for this part. 

[Amdt. 36–54, 67 FR 45235, July 8, 2002; Amdt. 
36–24, 67 FR 63196, Oct. 10, 2002; 68 FR 1512, 
Jan. 10, 2003; Amdt. 36–26, 70 FR 38749, July 5, 
2005; FAA Doc. No. FAA–2015–3782, Amdt. No. 
36–31, 82 FR 46131, Oct. 4, 2017]] 

A

PPENDIXES

C–E 

TO

P

ART

36 [R

ESERVED

] 

A

PPENDIX

F 

TO

P

ART

36—F

LYOVER

 

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

P

RIOR TO

D

ECEMBER

22, 1988 

PART A

—

GENERAL

 

Sec. 
F36.1 

Scope. 

PART B

—

NOISE MEASUREMENT

 

F36.101 

General test conditions. 

F36.103 

Acoustical measurement system. 

F36.105 

Sensing, recording, and reproducing 

equipment. 

F36.107 

Noise measurement procedures. 

F36.109 

Data recording, reporting, and ap-

proval. 

F36.111 

Flight procedures. 

PART C

—

DATA CORRECTION

 

F36.201 

Correction of data. 

F36.203 

Validity of results. 

PART D

—

NOISE LIMITS

 

F36.301 

Aircraft noise limits. 

PART A

—

GENERAL

 

Section F36.1 Scope. 

This appendix pre-

scribes noise level limits and procedures for 
measuring and correcting noise data for the 
propeller driven small airplanes specified in 
§§ 36.1 and 36.501(b). 

PART B

—

NOISE MEASUREMENT

 

Sec. F36.101 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 this axis. 

(b) The tests must be carried out under the 

following conditions: 

(1) There may be no precipitation. 
(2) Relative humidity may not be higher 

than 90 percent or lower than 30 percent. 

(3) Ambient temperature may not be above 

86 degrees F. or below 41 degrees F. at 33

′ 

above ground. If the measurement site is 
within 1 n.m. of an airport thermometer the 
airport reported temperature may be used. 

(4) Reported wind may not be above 10 

knots at 33

′ 

above ground. If wind velocities 

of more than 4 knots are reported, the flight 
direction must be aligned to within 

±

15 de-

grees of wind direction and flights with tail 

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