811
Federal Aviation Administration, DOT
Pt. 36, App. F
(d) The following atmospheric data, meas-
ured immediately before, after, or during
each test at the observation points pre-
scribed in section F36.101 of this appendix
must be reported:
(1) Air temperature and relative humidity.
(2) Maximum, minimum, and average wind
velocities.
(e) Comments on local topography, ground
cover, and events that might interfere with
sound recordings must be reported.
(f) 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 weights.
(4) Airspeed in knots for each overflight of
the measuring point.
(5) Engine performance in terms of revolu-
tions per minute and other relevant param-
eters for each overflight.
(6) Aircraft height in feet determined by a
calibrated altimeter in the aircraft, ap-
proved photographic techniques, or approved
tracking facilities.
(g) Aircraft speed and position and engine
performance parameters must be recorded at
an approved sampling rate sufficient to en-
sure compliance with the test procedures and
conditions of this appendix.
Sec. F36.111 Flight procedures.
(a) Tests to demonstrate compliance with
the noise level requirements of this appendix
must include at least six level flights over
the measuring station at a height of 1,000
′
±
30
′
and
±
10 degrees from the zenith when
passing overhead.
(b) Each test over flight must be con-
ducted:
(1) At not less than the highest power in
the normal operating range provided in an
Airplane Flight Manual, or in any combina-
tion of approved manual material, approved
placard, or approved instrument markings;
and
(2) At stabilized speed with propellers syn-
chronized and with the airplane in cruise
configuration, except that if the speed at the
power setting prescribed in this paragraph
would exceed the maximum speed authorized
in level flight, accelerated flight is accept-
able.
PART C
—
DATA CORRECTION
Sec. F36.201 Correction of data.
(a) Noise data obtained when the tempera-
ture is outside the range of 68 degrees F.
±
9
degrees F., or the relative humidity is below
40 percent, must be corrected to 77 degrees F.
and 70 percent relative humidity by a meth-
od approved by the FAA.
(b) The performance correction prescribed
in paragraph (c) of this section must be used.
It must be determined by the method de-
scribed in this appendix, and must be added
algebraically to the measured value. It is
limited to 5dB(A).
(c) The performance correction must be
computed by using the following formula:
Δ
dB
D
R C
V
y
=
−
−
+
⎧
⎨
⎪
⎩⎪
⎫
⎬
⎪
⎭⎪
60
20
11 430
50
10
50
log
( ,
/
Where:
D
50
= Takeoff distance to 50 feet at maximum
certificated takeoff weight.
R/C = Certificated best rate of climb (fpm).
V
y
= Speed for best rate of climb in the same
units as rate of climb.
(d) When takeoff distance to 50
′
is not list-
ed as approved performance information, the
figures of 2000 for single-engine airplanes and
1600
′
for multi-engine airplanes must be used.
Sec. F36.203
Validity of results.
(a) The test results must produce an aver-
age dB(A) and its 90 percent confidence lim-
its, the noise level being the arithmetic av-
erage of the corrected acoustical measure-
ments for all valid test runs over the meas-
uring point.
(b) The samples must be large enough to
establish statistically a 90 pecent confidence
limit not to exceed
±
1.5 dB(A). No test result
may be omitted from the averaging process,
unless omission is approved by the FAA.
PART D
—
NOISE LIMITS
Sec. F36.301 Aircraft noise limits.
(a) Compliance with this section must be
shown with noise data measured and cor-
rected as prescribed in Parts B and C of this
appendix.
(b) For airplanes for which application for
a type certificate is made on or after October
10, 1973, the noise level must not exceed 68
dB(A) up to and including aircraft weights of
1,320 pounds (600 kg.). For weights greater
than 1,320 pounds up to and including 3,630
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