5.21. Safety
wide. Again, the accident potential in this area reduces further, and with
this, some additional development types are allowed.
Safety zones are areas in which development should be more restrictive, in
terms of use and concentrations of people, due to the higher risks to public
safety. Issues to consider include aircraft accident potential zones, weapons
firing range safety zones, and explosive safety zones.
Military installations often engage in activities or contain facilities that, due
to public safety concerns, require special consideration by local jurisdictions
when evaluating compatibility. It is important to regulate land use near
military airfields in order to minimize damage from potential aircraft
accidents and to reduce air navigation hazards. To help mitigate potential
issues, the Department of Defense (DOD) has delineated Clear Zones (CZ)
and Accident Potential Zones (APZ) in the vicinity of airfield runways. APZs
are usually divided into APZ I and APZ II. Each zone was developed based on
the statistical review of aircraft accidents. Studies show that most mishaps
occur on or near the runway, predominately along its extended centerline.
Key Terms
Airport Operations Area. The Airport Operations Area (AOA) is an area that
encompasses all the airfield’s approach or departure airspace including the
circling space.
Accident Potential Zone I (APZ I). APZ I is an area beginning at the end of
each clear zone and continuing out to a length of 5,000 feet by 3,000 feet
wide. This area has a lower potential for accidents and therefore has less
restrictive development restrictions recommended.
Accident Potential Zone II (APZ II). APZ II is an area that begins at the end
of each APZ I and extends an additional 7,000 feet in length by 3,000 feet
June 2017
Avigation Easement. An avigation easement refers to a property right
acquired from a landowner which protects the use of airspace above a
specified height, and can impose limitations on use of the land subject to the
easement.
Bird / Wildlife Aircraft Strike Hazard (BASH). BASH refers to the likely
occurrence for a collision between an airborne animal (usually a bird) or an
animal on the ground on the runway and a man‐made vehicle, particularly
aircraft.
BASH Relevancy Area. The BASH Relevancy Area is a five‐statute mile area
from the AOA, including the runway. This area has been determined by the
FAA as an area where BASH incidences are likely to occur due to the types of
flying operations that occur near the airfield. Such operations are typically at
slower speeds and lower altitudes resulting in a greater chance for a BASH
incident.
Clear Zone (CZ). The CZ begins at the end of each runway measuring
3,000 feet wide and extending outward to a length of 3,000 feet from the
end of each runway. This area has the highest potential of an aircraft
mishap. This area should be kept clear of all structures, including fences.
Frangible Pole / Object. A frangible pole / object is a pole or object
constructed with materials that are designed to break away at impact
instead of remaining erect. The break‐away design reduces the impact and
potential severity of the incident in the event of a collision with the pole /
object.
Background Report
Page 5‐89