the Aviation Dictionary

aperiodic-type compass - A magnetic compass in
which the floating magnet assembly is fitted with
damping vanes to increase the period of its oscillations.
aperture - A device used to control the bandwidth of an
antenna.
API scale - A scale that has been developed by the
American Petroleum Institute to measure the specific
gravity of a liquid.
apogee - The point at which an orbiting vehicle is the
greatest distance from the center of the object it is
circling.
apparent power - In an AC circuit, the product of RMS
(Root Mean Square) current and RMS voltage,
expressed in volt-amperes
apparent weight - The weight of the object plus or
minus any outside influence. The apparent weight of an
object immersed in water would be the weight of the
object minus any buoyancy. The apparent weight of an
object in an elevator would be the weight of the object
plus or minus the effects of acceleration due to the
elevator moving upward or downward.
aperiodic-type compass approach/departure control service
approach control service - Air traffic control service
provided by an approach control facility for arriving
and departing VFRIIFR aircraft and, on occasion,
enroute aircraft. At some airports not served by an
approach control facility, the ARTCC provides limited
approach control service.
approach end of runway (AER)- The first portion of
the runway available for landing. If the runway
threshold is dis~laced, the disvlaced threshold
latitude/longitude is the AER.
approach fix - From a database coding standpoint, an
approach fix is considered to be an identifiable point in
space from the intermediate fix (IF) inbound. A fix
located from the initial approach fix (IAF) to the
intermediate fix is considered to be associated with the
approach transition or feeder route.
approach gate - An imaginary point used within ATC
as a basis for vectoring aircraft to the final approach
course. The gate will be established along the final
approach course 1 mile from the final approach fix on
the side away from the airport and will be no closer
than 5 miles from the landing threshold.
appliance - Any instrument, equipment, mechanism, approach light system (ALS) - An airport lighting
part, apparatus, or accessory, including facility which provides visual guidance to landing
communications equipment, used or intended to be aircraft by radiating light beams in a directional pattern
used in operating or controlling an aircraft in flight. An by which the pilot aligns the aircraft with the extended
appliance is installed or attached to the aircraft, but is centerline of the runway on his final approach for
not part of the engine, airframe, or propeller.
landing. Condenser Discharge Sequential Flashing
LightdSequenced Flashing Lights may be installed in
applicability - Something that applies to andlor affects
conjunction with the ALS at some airports.
another.
approach lights - High intensity lights along the
application - A basic level of learning where the
approach end of an instrument runway that aid the pilot
student puts something to use that has been learned and
in the transition from instruments to visual flight at the
understood.
end of an instrument approach.
step - The third step of the teaching
approach sequence - The order in which aircraft are
process, where the student perfoms the procedure or
positioned while on approach or awaiting approach
demonstrates the knowledge required in the lesson. In
clearance.
the telling-and-doing technique of flight instruction,
this step consists of the student doing the procedure approach speed - The recommended speed contained in
while explaining it.
aircraft manuals used by pilots when making an
approach to landing. This speed will vary for different
approach - The flight of an airplane just preceding the
segments of an approach as well as for aircraft weight
landing.
and configuration.
approach clearance - Authorization by ATC for a pilot
approach with vertical guidance (APV) - An
to conduct an instrument approach. The type of
instrument approach based on a navigation system that
instrument approach for which a clearance and other
is not required to meet the precision approach
pertinent information is provided in the approach
standards of ICAO Annex 10 but provides course and
clearance when required.
glidepath - deviation information. Raro-VNAV, LDA
A
approach control - A terminal air traffic control facility with glidepath, LNAVNNAV and LPV are APV
providing approach control service.
approaches.
approach control facility - A terminal ATC facility
that provides approach control service in a terminal
area.
approach/departure control service - An air traffic
control service provided by an approach control facility
for arriving and departing VFRflFR aircraft and, on
occasion, enroute aircraft.
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