Federal Aviation Administration, DOT

Pt. 36, App. H

(Secs. 313(a), 603, and 611(b), Federal Aviation
Act of 1958 as amended (49 U.S.C. 1354(a),
1423, and 1431(b)); sec. 6(c), Department of
Transportation Act (49 U.S.C. 1655 (c)); Title
I, National Environmental Policy Act of 1969
(42 U.S.C. 4321 et seq.); E. O. 11514, March 5,
1970 and 14 CFR 11.45).
[Amdt. 36-16, 53 FR 47400, Nov. 22, 1988; 53 FR
50157, Dec. 13, 1988, as amended by Amdt. 36-
22, 64 FR 55602, Oct. 13, 1999; Amdt. 36-54, 67
FR 45236, July 8, 2002; Amdt. 36-27, 70 FR
45504, Aug. 5, 2005; Amdt. 36-28, 71 FR 532,
Jan. 4, 2006; FAA Doc. No. FAA-2015-3782,
Amdt. No. 36-31, 82 FR 46131, Oct. 4, 2017]

APPENDIX H TO PART 36 - NOISE REQUIREMENTS
FOR
HELICOPTERS
UNDER SUBPART H
PART A - REFERENCE CONDITIONS

Sec.
H36.1 General.
H36.3 Reference Test Conditions.
H36.5 Symbols and Units.
PART B - NOISE MEASUREMENT UNDER

Section 36.801

H36.101 Noise certification test and measurement
conditions.
H36.103 Takeoff test conditions.
H36.105 Flyover test conditions.
H36.107 Approach test conditions.
H36.109 Measurement of helicopter noise received on the ground.
H36.111 Reporting and correcting measured
data.
H36.113 Atmospheric attenuation of sound.
PART C - NOISE EVALUATION AND CALCULATION
UNDER Section 36.803

H36.201 Noise evaluation in EPNdB.
H36.203 Calculation of noise levels.
H36.205 Detailed data correction procedures.
PART D - NOISE LIMITS UNDER

Section 36.805

H36.301 Noise measurement, evaluation, and calculation.
H36.303 [Reserved]
H36.305 Noise levels.

spaschal on DSK3GDR082PROD with CFR

PART A - REFERENCE CONDITIONS

Section H36.1 General. This appendix prescribes noise requirements for helicopters
specified under Section 36.1, including:
(a) The conditions under which helicopter
noise certification tests under Part H must
be conducted and the measurement procedures that must be used under Section 36.801 to
measure helicopter noise during each test;
(b) The procedures which must be used
under Section 36.803 to correct the measured data to
the reference conditions and to calculate the
noise evaluation quantity designated as Effective Perceived Noise Level (EPNL); and

(c) The noise limits for which compliance
must be shown under Section 36.805.
Section H36.3 Reference Test Conditions.
(a) Meteorological conditions. Aircraft position, performance data and noise measurements must be corrected to the following
noise certification reference atmospheric
conditions which shall be assumed to exist
from the surface to the aircraft altitude:
(1) Sea level pressure of 2,116 psf (1,013.25
hPa).
(2) Ambient temperature of 77 degrees F (25
degrees C).
(3) Relative humidity of 70 percent.
(4) Zero wind.
(b) Reference test site. The reference test
site is flat and without line-of-sight obstructions across the flight path that encompasses the 10 dB down points.
(c) Takeoff reference profile. (1) Figure H1 illustrates a typical takeoff profile, including
reference conditions.
(2) The reference flight path is defined as a
straight line segment inclined from the
starting point (1,640 feet (500 meters) from
the center microphone location and 65 feet
(20 meters) above ground level) at a constant
climb angle b defined by the certificated best
rate of climb and Vy for minimum engine
performance. The constant climb angle b is
derived from the manufacturer-s data (approved by the FAA) to define the flight profile for the reference conditions. The constant climb angle b is drawn through Cr and
continues, crossing over station A, to the position corresponding to the end of the type
certification takeoff path represented by position Ir.
(d) Level flyover reference profile. The beginning of the level flyover reference profile is
represented by helicopter position Dr (Figure
H2). The helicopter approaches position Dr in
level flight 492 feet above ground level as
measured at Station A. Reference airspeed
must be either 0.9VH; 0.9VNE; 0.45VH + 65 kts
(0.45VH + 120km/h); or 0.45VNE + 65kts (0.45VNE
+ 120 km/h), whichever of the four speeds is
least. The helicopter crosses directly overhead station A in level flight and proceeds to
position Jr.
(e) For noise certification purposes, VH is
defined as the airspeed in level flight obtained using the minimum specified engine
torque corresponding to maximum continuous power available for sea level pressure of
2,116 psf (1,013.25 hPa) at 77 SectionF (25 SectionC) ambient
conditions at the relevant maximum certificated weight. The value of VNE is the neverexceed airspeed. The values of VH and VNE
that are used for noise certification must be
listed in the approved Rotorcraft Flight
Manual.
(f) Approach reference profile. (1) Figure H3
illustrates approach profile, including reference conditions.

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