835 

Federal Aviation Administration, DOT 

Pt. 36, App. J 

L

AMAX

and the integration interval (in sec-

onds) for inclusion in the noise data sub-
mitted as part of the reporting requirements 
under section J36.111(b) of this appendix. 

Section J36.111 Reporting Requirements. 

(a) 

General. 

Data representing physical 

measurements, and corrections to measured 
data, including corrections to measurements 
for equipment response deviations, must be 
recorded in permanent form and appended to 
the record. Each correction is subject to 
FAA approval. 

(b) 

Data reporting. 

After the completion of 

the test the following data must be included 
in the test report furnished to the FAA: 

(1) Measured and corrected sound levels ob-

tained with equipment conforming to the 
standards prescribed in section J36.109 of this 
appendix; 

(2) The type of equipment used for meas-

urement and analysis of all acoustic, aircraft 
performance and flight path, and meteoro-
logical data; 

(3) The atmospheric environmental data 

required to demonstrate compliance with 
this appendix, measured throughout the test 
period; 

(4) Conditions of local topography, ground 

cover, or events which may interfere with 
the sound recording; 

(5) The following helicopter information: 
(i) Type, model, and serial numbers, if any, 

of helicopter, engine(s) and rotor(s); 

(ii) Gross dimensions of helicopter, loca-

tion of engines, rotors, type of antitorque 
system, number of blades for each rotor, and 
reference operating conditions for each en-
gine and rotor; 

(iii) Any modifications of non-standard 

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

(iv) Maximum takeoff weight for which 

certification under this appendix is re-
quested; 

(v) Aircraft configuration, including land-

ing gear positions; 

(vi) V

H

or V

NE

(whichever is less) and the 

adjusted reference airspeed; 

(vii) Aircraft gross weight for each test 

run; 

(viii) Indicated and true airspeed for each 

test run; 

(ix) Ground speed, if measured, for each 

run; 

(x) Helicopter engine performance as deter-

mined from aircraft instruments and manu-
facturer’s data; and 

(xi) Aircraft flight path above ground 

level, referenced to the elevation of the noise 
measurement station, in feet, determined by 
an FAA-approved method which is inde-
pendent of normal flight instrumentation, 
such as radar tracking, theodolite triangula-
tion, laser trajectography, or photoscaling 
techniques; and 

(6) Helicopter position and performance 

data required to make the adjustments pre-
scribed under section J36.205 of this appendix 
and to demonstrate compliance with the per-
formance and position restrictions pre-
scribed under section J36.105 of this appendix 
must be recorded at an FAA-approved sam-
pling rate. 

Section J36.113 [Reserved] 

P

ART

C—N

OISE

E

VALUATION AND

 

C

ALCULATIONS

U

NDER

§ 36.803 

Section J36.201 Noise Evaluation in SEL. 

The noise evaluation measure shall be the 

sound exposure level (SEL) in units of dB(A) 
as prescribed under section J36.109(b) of this 
appendix. The SEL value for each flyover 
may be directly determined by use of an in-
tegrating sound level meter. Specifications 
for the integrating sound level meter and re-
quirements governing the use of such instru-
mentation are prescribed under section 
J36.109 of this appendix. 

Section J36.203 Calculation of Noise Levels. 

(a) To demonstrate compliance with the 

noise level limits specified under section 
J36.305 of this appendix, the SEL noise levels 
from each valid flyover, corrected as nec-
essary to reference conditions under section 
J36.205 of this appendix, must be 
arithmetically averaged to obtain a single 
SEL dB(A) mean value for the flyover series. 
No individual flyover run may be omitted 
from the averaging process, unless otherwise 
specified or approved by the FAA. 

(b) The minimum sample size acceptable 

for the helicopter flyover certification meas-
urements is six. The number of samples must 
be large enough to establish statistically a 90 
percent confidence limit that does not ex-
ceed 

±

1.5 dB(A). 

(c) All data used and calculations per-

formed under this section, including the cal-
culated 90 percent confidence limits, must be 
documented and provided under the report-
ing requirements of section J36.111 of this 
appendix. 

Section J36.205 Detailed Data Correction 

Procedures. 

(a) When certification test conditions 

measured under part B of this appendix differ 
from the reference test conditions prescribed 
under section J36.3 of this appendix, appro-
priate adjustments shall be made to the 
measured noise data in accordance with the 
methods set out in paragraphs (b) and (c) of 
this section. At minimum, appropriate ad-
justments shall be made for off-reference al-
titude and for the difference between ref-
erence airspeed and adjusted reference air-
speed. 

(b) The adjustment for off-reference alti-

tude may be approximated from: 

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