Apron--A defined area, on an airfield, intended to accommodate aircraft for the purposes of loading or
unloading passengers or cargo, refueling, parking or maintenance.
Apron, Aircraft Access--See Apron, Hangar Access.
Apron, Alert--A designated area for multiple alert aircraft parking.
Apron Edge--See Edge of Apron.
Apron, Hangar Access--Hangar access aprons are paved areas connecting hangars with adjacent
Apron, Holding (Engine Run up Area)--A paved area adjacent to the taxiway near the runway ends
where final preflight warmup and engine and instrument checks are performed.
Apron, Parking--A parking apron is a designated paved area on an airfield intended to accommodate
fixed-and rotary-wing aircraft for parking.
Arming and Disarming--The loading
of missiles, rockets,
Arrestment Capable Aircraft--An aircraft whose flight manual specifies arrestment procedures.
Autorotation Lane--A helicopter landing lane or designated area on a runway used for practicing
landings under simulated engine failure or certain other emergency conditions. Also known as a slide
area when designed specifically for USAF skid-type helicopters.
Aviation Facility--The combination of land, airspace, pavements and buildings which are needed to
support an aviation movement or action. An aviation facility can be an airfield, heliport, or helipad.
The aviation facility includes "airside" and "landside" facilities.
Aviation Intermediate Maintenance (AVIM)--For Army, units that provide mobile, responsive "one-
stop" maintenance and repair of equipment to return to user.
Aviation Movement or Action--An aviation movement or action includes but is not limited to: the
landing and take-off of aircraft; readiness of aircraft; flight training of pilots; loading and unloading of
aircraft; and the maintenance and fueling of aircraft.
Aviation Unit Maintenance (AVUM)--For Army, activities staffed and equipped to perform high
frequency "on aircraft" maintenance tasks required to retain or return aircraft to a serviceable condition.
Avigation Easement--A legal right obtained from a property owner to operate aircraft over that
property and to restrict the height of any construction or growth on that property.
Beam Wind Component--The wind velocities perpendicular to the axis of the runway centerline used
to measure the degree by which a runway pattern covers incident wind.
Blast Protective Area--An area protected by pavement construction at the ends of runways and
taxiways against jet blast erosion.
Circling Approach Area--The area in which aircraft circle to land under visual conditions.
Clear Zone--A surface on the ground or water beginning at the runway end and symmetrical about the
runway centerline extended.
Compass Calibration Pad--
An aircraft compass calibration pad
is a paved area
electromagnetically quiet zone where an aircraft's compass is calibrated.