Pilot/Controller Glossary
5/19/22
pilot/controller communications under the general
term “airspeed.”
(Refer to 14 CFR Part 1.)
b.
True Airspeed
−
The airspeed of an aircraft
relative to undisturbed air. Used primarily in flight
planning and en route portion of flight. When used in
pilot/controller communications, it is referred to as
“true airspeed” and not shortened to “airspeed.”
AIRSPACE RESERVATION
−
The term used in
oceanic ATC for airspace utilization under prescribed
conditions normally employed for the mass
movement of aircraft or other special user
requirements which cannot otherwise be accom-
plished. Airspace reservations must be classified as
either “moving” or “stationary.”
(See MOVING AIRSPACE RESERVATION)
(See STATIONARY AIRSPACE RESERVATION.)
(See ALTITUDE RESERVATION.)
AIRSTART
−
The starting of an aircraft engine while
the aircraft is airborne, preceded by engine shutdown
during training flights or by actual engine failure.
AIRWAY
−
A Class E airspace area established in the
form of a corridor, the centerline of which is defined
by radio navigational aids.
(See FEDERAL AIRWAYS.)
(See ICAO term AIRWAY.)
(Refer to 14 CFR Part 71.)
(Refer to AIM.)
AIRWAY [ICAO]
−
A control area or portion thereof
established in the form of corridor equipped with
radio navigational aids.
AIRWAY BEACON
−
Used to mark airway segments
in remote mountain areas. The light flashes Morse
Code to identify the beacon site.
(Refer to AIM.)
AIS
−
(See AERONAUTICAL INFORMATION
SERVICES.)
AIT
−
(See AUTOMATED INFORMATION
TRANSFER.)
ALERFA (Alert Phase) [ICAO]
−
A situation wherein
apprehension exists as to the safety of an aircraft and
its occupants.
ALERT
−
A notification to a position that there
is an aircraft-to-aircraft or aircraft-to-airspace
conflict, as detected by Automated Problem
Detection (APD).
ALERT AREA
−
(See SPECIAL USE AIRSPACE.)
ALERT NOTICE (ALNOT)
−
A request originated
by a flight service station (FSS) or an air route traffic
control center (ARTCC) for an extensive commu-
nication search for overdue, unreported, or missing
aircraft.
ALERTING SERVICE
−
A service provided to notify
appropriate organizations regarding aircraft in need
of search and rescue aid and assist such organizations
as required.
ALNOT
−
(See ALERT NOTICE.)
ALONG
−
TRACK DISTANCE (ATD)
−
The hori-
zontal distance between the aircraft’s current position
and a fix measured by an area navigation system that
is not subject to slant range errors.
ALPHANUMERIC DISPLAY
−
Letters and numer-
als used to show identification, altitude, beacon code,
and other information concerning a target on a radar
display.
(See AUTOMATED RADAR TERMINAL
SYSTEMS.)
ALTERNATE AERODROME [ICAO]
−
An aero-
drome to which an aircraft may proceed when it
becomes either impossible or inadvisable to proceed
to or to land at the aerodrome of intended landing.
Note: The aerodrome from which a flight departs
may also be an en-route or a destination alternate
aerodrome for the flight.
ALTERNATE AIRPORT
−
An airport at which an
aircraft may land if a landing at the intended airport
becomes inadvisable.
(See ICAO term ALTERNATE AERODROME.)
ALTIMETER SETTING
−
The barometric pressure
reading used to adjust a pressure altimeter for
variations in existing atmospheric pressure or to the
standard altimeter setting (29.92).
(Refer to 14 CFR Part 91.)
(Refer to AIM.)
ALTITUDE
−
The height of a level, point, or object
measured in feet Above Ground Level (AGL) or from
Mean Sea Level (MSL).
(See FLIGHT LEVEL.)
a.
MSL Altitude
−
Altitude expressed in feet
measured from mean sea level.
PCG A
−
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