Definitions

Air Installations Compatible Use Zones (AICUZ)
The noise zones and the accident potential zones together form the AICUZ for an air installation.

Accident Potential Zone (APZ)
An area beyond the airfield runway where an aircraft mishap is most likely to occur if one occurs. It does not indicate a probability of an accident occurring, but is to be used for planning purposes. Based on historical data, aircraft accidents are most likely to occur near the airfield runway during aircraft takeoff and landing. An APZ is calculated for aircraft flight tracks to and from the airfield runway based on the number of aircraft operations.

Noise Contour
A line connecting points of similar day-night average sound levels measured from a specific noise source. At Naval air facilities, the primary noise sources are aircraft operations and aircraft engine maintenance operations.