949
Federal Aviation Administration, DOT
Pt. 36, App. B
symmetrical if they are longitudinally with-
in 33 feet (
±
10 meters) of each other.
Section B36.5 Maximum Noise Levels
Except as provided in section B36.6 of this
appendix, maximum noise levels, when deter-
mined in accordance with the noise evalua-
tion methods of appendix A of this part, may
not exceed the following:
(a) For acoustical changes to Stage 1 air-
planes, regardless of the number of engines,
the noise levels prescribed under § 36.7(c) of
this part.
(b) For any Stage 2 airplane regardless of
the number of engines:
(1) Flyover: 108 EPNdB for maximum
weight of 600,000 pounds or more; for each
halving of maximum weight (from 600,000
pounds), reduce the limit by 5 EPNdB; the
limit is 93 EPNdB for a maximum weight of
75,000 pounds or less.
(2) Lateral and approach: 108 EPNdB for
maximum weight of 600,000 pounds or more;
for each halving of maximum weight (from
600,000 pounds), reduce the limit by 2 EPNdB;
the limit is 102 EPNdB for a maximum
weight of 75,000 pounds or less.
(c) For any Stage 3 airplane:
(1) Flyover.
(i) For airplanes with more than 3 engines:
106 EPNdB for maximum weight of 850,000
pounds or more; for each halving of max-
imum weight (from 850,000 pounds), reduce
the limit by 4 EPNdB; the limit is 89 EPNdB
for a maximum weight of 44,673 pounds or
less;
(ii) For airplanes with 3 engines: 104
EPNdB for maximum weight of 850,000
pounds or more; for each halving of max-
imum weight (from 850,000 pounds), reduce
the limit by 4 EPNdB; the limit is 89 EPNdB
for a maximum weight of 63,177 pounds or
less; and
(iii) For airplanes with fewer than 3 en-
gines: 101 EPNdB for maximum weight of
850,000 pounds or more; for each halving of
maximum weight (from 850,000 pounds), re-
duce the limit by 4 EPNdB; the limit is 89
EPNdB for a maximum weight of 106,250
pounds or less.
(2) Lateral, regardless of the number of en-
gines: 103 EPNdB for maximum weight of
882,000 pounds or more; for each halving of
maximum weight (from 882,000 pounds), re-
duce the limit by 2.56 EPNdB; the limit is 94
EPNdB for a maximum weight of 77,200
pounds or less.
(3) Approach, regardless of the number of
engines: 105 EPNdB for maximum weight of
617,300 pounds or more; for each halving of
maximum weight (from 617,300 pounds), re-
duce the limit by 2.33 EPNdB; the limit is 98
EPNdB for a maximum weight of 77,200
pounds or less.
(d) For any Stage 4 airplane, the flyover,
lateral, and approach maximum noise levels
are prescribed in Chapter 4, Paragraph 4.4,
Maximum Noise Levels, and Chapter 3, Para-
graph 3.4, Maximum Noise Levels, of the
International Civil Aviation Organization
(ICAO) Annex 16, Environmental Protection,
Volume I, Aircraft Noise, Third Edition,
July 1993, Amendment 7, effective March 21,
2002. [Incorporated by reference, see § 36.6].
Section B36.6 Trade-Offs
Except when prohibited by sections
36.7(c)(1) and 36.7(d)(1)(ii), if the maximum
noise levels are exceeded at any one or two
measurement points, the following condi-
tions must be met:
(a) The sum of the exceedance(s) may not
be greater than 3 EPNdB;
(b) Any exceedance at any single point
may not be greater than 2 EPNdB, and
(c) Any exceedance(s) must be offset by a
corresponding amount at another point or
points.
Section B36.7 Noise Certification Reference
Procedures and Conditions
(a) General conditions:
(1) All reference procedures must meet the
requirements of section 36.3 of this part.
(2) Calculations of airplane performance
and flight path must be made using the ref-
erence procedures and must be approved by
the FAA.
(3) Applicants must use the takeoff and ap-
proach reference procedures prescribed in
paragraphs (b) and (c) of this section.
(4) [Reserved]
(5) The reference procedures must be deter-
mined for the following reference conditions.
The reference atmosphere is homogeneous in
terms of temperature and relative humidity
when used for the calculation of atmospheric
absorption coefficients.
(i) Sea level atmospheric pressure of 2116
pounds per square foot (psf) (1013.25 hPa);
(ii) Ambient sea-level air temperature of 77
°
F (25
°
C,
i.e., ISA+10
°
C);
(iii) Relative humidity of 70 per cent;
(iv) Zero wind.
(v) In defining the reference takeoff flight
path(s) for the takeoff and lateral noise
measurements, the runway gradient is zero.
(b) Takeoff reference procedure:
The takeoff reference flight path is to be
calculated using the following:
(1) Average engine takeoff thrust or power
must be used from the start of takeoff to the
point where at least the following height
above runway level is reached. The takeoff
thrust/power used must be the maximum
available for normal operations given in the
performance section of the airplane flight
manual under the reference atmospheric
conditions given in section B36.7(a)(5).
(i) For Stage 1 airplanes and for Stage 2
airplanes that do not have jet engines with a
bypass ratio of 2 or more, the following
apply:
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