661 

Federal Aviation Administration, DOT 

§ 150.7 

(d) Acceptance of a noise exposure 

map does not constitute an FAA deter-
mination that any specific parcel of 
land lies within a particular noise con-
tour. Responsibility for interpretation 
of the effects of noise contours upon 
subjacent land uses, including the rela-
tionship between noise contours and 
specific properties, rests with the spon-
sor or with other state or local govern-
ment. 

[Doc. No. 18691, 49 FR 49269, Dec. 18, 1984, as 
amended by Amdt. 150–4, 69 FR 57625, Sept. 
24, 2004] 

§ 150.7

Definitions. 

As used in this part, unless the con-

text requires otherwise, the following 
terms have the following meanings. 

Airport 

means any public use airport, 

including heliports, as defined by the 
ASNA Act, including: (a) Any airport 
which is used or to be used for public 
purposes, under the control of a public 
agency, the landing area of which is 
publicly owned; (b) any privately 
owned reliever airport; and (c) any pri-
vately owned airport which is deter-
mined by the Secretary to enplane an-
nually 2,500 or more passengers and re-
ceive scheduled passenger service of 
aircraft, which is used or to be used for 
public purposes. 

Airport noise compatibility program 

and 

program 

mean that program, and all re-

visions thereto, reflected in documents 
(and revised documents) developed in 
accordance with appendix B of this 
part, including the measures proposed 
or taken by the airport operator to re-
duce existing noncompatible land uses 
and to prevent the introduction of ad-
ditional noncompatible land uses with-
in the area. 

Airport Operator 

means, the operator 

of an airport as defined in the ASNA 
Act. 

ASNA Act 

means 49 U.S.C. 47501 

et seq. 

Average sound level 

means the level, 

in decibels, of the mean-square, A- 
weighted sound pressure during a speci-
fied period, with reference to the 
square of the standard reference sound 
pressure of 20 micropascals. 

Compatible land use 

means the use of 

land that is identified under this part 
as normally compatible with the out-
door noise environment (or an ade-
quately attenuated noise level reduc-

tion for any indoor activities involved) 
at the location because the yearly day- 
night average sound level is at or below 
that identified for that or similar use 
under appendix A (Table 1) of this part. 

Day-night average sound level 

(DNL) 

means the 24-hour average sound level, 
in decibels, for the period from mid-
night to midnight, obtained after the 
addition of ten decibels to sound levels 
for the periods between midnight and 7 
a.m., and between 10 p.m., and mid-
night, local time. The symbol for DNL 
is L

dn

. 

Noise exposure map 

means a scaled, 

geographic depiction of an airport, its 
noise contours, and surrounding area 
developed in accordance with section 
A150.1 of Appendix A of this part, in-
cluding the accompanying documenta-
tion setting forth the required descrip-
tions of forecast aircraft operations at 
that airport during the fifth calendar 
year (or later) beginning after submis-
sion of the map, together with the 
ways, if any, those operations will af-
fect the map (including noise contours 
and the forecast land uses). 

Noise level reduction 

(NLR) means the 

amount of noise level reduction in 
decibels achieved through incorpora-
tion of noise attenuation (between out-
door and indoor levels) in the design 
and construction of a structure. 

Noncompatible land use 

means the use 

of land that is identified under this 
part as normally not compatible with 
the outdoor noise environment (or an 
adequately attenuated noise reduction 
level for the indoor activities involved 
at the location) because the yearly 
day-night average sound level is above 
that identified for that or similar use 
under appendix A (Table 1) of this part. 

Regional Airports Division Manager 

means the Airports Division Manager 
having responsibility for the geo-
graphic area in which the airport in 
question is located. 

Restriction affecting flight procedures 

means any requirement, limitation, or 
other action affecting the operation of 
aircraft, in the air or on the ground. 

Sound exposure level 

means the level, 

in decibels, of the time integral of 
squared A-weighted sound pressure 
during a specified period or event, with 
reference to the square of the standard 
reference sound pressure of 20 

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