814 

14 CFR Ch. I (1–1–19 Edition) 

Pt. 36, App. G 

tracking, theodolite triangulation, or photo-
graphic scaling techniques. 

(g) The following airplane information 

must be reported: 

(1) Type, model, and serial numbers (if any) 

of airplanes, engines, and propellers; 

(2) Any modifications or nonstandard 

equipment likely to affect the noise charac-
teristics of the airplane; 

(3) Maximum certificated takeoff weight; 
(4) For each test flight, airspeed and ambi-

ent temperature at the flyover altitude over 
the measuring site determined by properly 
calibrated instruments; 

(5) For each test flight, engine perform-

ance parameters, such as manifold pressure 
or power, propeller speed (rpm) and other rel-
evant parameters. Each parameter must be 
determined by properly calibrated instru-
ments. For instance, propeller RPM must be 
validated by an independent device accurate 
to within 

±

1 percent, when the airplane is 

equipped with a mechanical tachometer. 

(6) Airspeed, position, and performance 

data necessary to make the corrections re-
quired in section G36.201 of this appendix 
must be recorded by an approved method 
when the airplane is directly over the meas-
uring site. 

Sec. G36.111 Flight Procedures. 

(a) The noise measurement point is on the 

extended centerline of the runway at a dis-
tance of 8200 ft (2500 m) from the start of 
takeoff roll. The aircraft must pass over the 
measurement point within 

±

10 degrees from 

the vertical and within 20% of the reference 
altitude. The flight test program shall be ini-
tiated at the maximum approved takeoff 
weight and the weight shall be adjusted back 
to this maximum weight after each hour of 
flight time. Each flight test must be con-
ducted at the speed for the best rate of climb 
(V

y

) 

±

5 knots (

±

9 km/hour) indicated airspeed. 

All test, measurement, and data correction 
procedures must be approved by the FAA. 

(b) The takeoff reference flight path must 

be calculated for the following atmospheric 
conditions: 

(1) Sea level atmospheric pressure of 1013.25 

mb (013.25 hPa); 

(2) Ambient air temperature of 59 

°

F (15 

°

C); 

(3) Relative humidity of 70 percent; and 
(4) Zero wind. 
(c) The takeoff reference flight path must 

be calculated assuming the following two 
segments: 

(1) First segment. 
(i) Takeoff power must be used from the 

brake release point to the point at which the 
height of 50 ft (15m) above the runway is 
reached. 

(ii) A constant takeoff configuration se-

lected by the applicant must be maintained 
through this segment. 

(iii) The maximum weight of the airplane 

at brake-release must be the maximum for 
which noise certification is requested. 

(iv) The length of this first segment must 

correspond to the airworthiness approved 
value for a takeoff on a level paved runway 
(or the corresponding value for seaplanes). 

(2) Second segment. 
(i) The beginning of the second segment 

corresponds to the end of the first segment. 

(ii) The airplane must be in the climb con-

figuration with landing gear up, if retract-
able, and flap setting corresponding to nor-
mal climb position throughout this second 
segment. 

(iii) The airplane speed must be the speed 

for the best rate of climb (V

y

). 

(iv) For airplanes equipped with fixed pitch 

propellers, takeoff power must be main-
tained throughout the second segment. For 
airplanes equipped with variable pitch or 
constant speed propellers, takeoff power and 
rpm must be maintained throughout the sec-
ond segment. If airworthiness limitations do 
not allow the application of takeoff power 
and rpm up to the reference point, then take-
off power and rpm must be maintained for as 
long as is permitted by such limitations; 
thereafter, maximum continuous power and 
rpm must be maintained. Maximum time al-
lowed at takeoff power under the airworthi-
ness standards must be used in the second 
segment. The reference height must be cal-
culated assuming climb gradients appro-
priate to each power setting used. 

PART C

—

DATA CORRECTIONS

 

Sec. G36.201 Corrections to Test Results. 

(a) These corrections account for the ef-

fects of: 

(1) Differences in atmospheric absorption 

of sound between meteorological test condi-
tions and reference conditions. 

(2) Differences in the noise path length be-

tween the actual airplane flight path and the 
reference flight path. 

(3) The change in the helical tip Mach 

number between test and reference condi-
tions. 

(4) The change in the engine power between 

test and reference conditions. 

(b) Atmospheric absorption correction is 

required for noise data obtained when the 
test conditions are outside those specified in 
Figure G1. Noise data outside the applicable 
range must be corrected to 59 F and 70 per-
cent relative humidity by an FAA approved 
method. 

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