Chapter 2
AICUZ and ICUZ studies are used to graphically illustrate noise levels and provide a basis for
land use management and impact mitigation. The primary means of noise assessment is
mathematical modeling and computer simulation. Guidance regarding when to conduct noise
studies is contained in the environmental directive for each service.
2.4.4.1.1. Fixed-Wing Aircraft Noise. Fixed-wing aircraft noise levels generated at aviation
facilities are modeled using the current version of the NOISEMAP computer model. Of
particular interest to facility planning for fixed-wing aircraft facilities is the land near areas
used for engine run-up and testing and those land areas below the extended approach-
departure path of runways.
2.4.4.1.2. Rotary-Wing Noise. Rotary-wing aircraft create a different class of noise which is
described as having high-level, low-frequency energy. These noise levels create vibrations
which vary greatly from that generated by fixed-wing aircraft.
Helicopter noise
measurement and modeling is primarily an Army initiative, and the latest modeling
techniques for assessing rotary-wing aircraft noise is contained in NOISEMAP or the
Helicopter Noise Model (HNM) computer noise program.
2.4.4.1.3. Noise Contour Maps. Noise levels generated from the activities of fixed- and
rotary-wing operations are identified using contours which delineate areas of equal sound
pressure impact on the areas surrounding the source of the noise. Noise levels are expressed
in Ldn (day/night average noise level) and noise contours provide a quantified diagram of the
noise levels. Noise contours are illustrated on airfield general site plans, Installation Land
Use Compatibility Plans, and/or Base Comprehensive Plans. Noise contours from other
sources, such as firing ranges, should also be shown on the noise contour map. In addition,
the noise contour maps should show the imaginary airspace such as the runway primary
surface, clear zone, APZ 1, and APZ 2. Through the establishment of noise contour maps,
potential noise sensitive areas on and off the aviation facility will be identified.
2.4.4.2. Requirement For Analysis of Noise Impact. An Environmental Impact Statement is
required to analyze a noise impact. An EA is required when: (1) a project or facility is proposed
within a noise sensitive area; (2) there is a change in flight operational procedures; or (3) the
quality of the human environment is significantly affected by a change in aircraft noise.
2.4.5. Instrumented Runway Studies. The requirement to conduct an instrumented runway study is
issued by the functional proponent. It is important to recognize that instrument landing capability
provides for aircraft approaches at very low altitude ceilings or visibility distance minimums.
Consequently, these lower approach minimums demand greater safety clearances, larger approach
surfaces, and greater separation from potential obstacles or obstructions to air navigation.
2.5. Siting Aviation Facilities:
NOTE: While the general siting principles below are applicable to Navy aviation facilities, see
MIL-HDBK-1021/1, General Concepts for Airfield Pavement Design, and NAVFAC P-80 for Navy-
specific data and contacts.
2.5.1. Location. The general location of an aviation facility is governed by many factors, including
base conversions, overall defense strategies, geographic advantages, mission realignment, security,
and personnel recruitment. These large-scale considerations are beyond the scope of this manual.
The information in this chapter provides guidelines for siting aviation facilities where the general
location has been previously defined.
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