Aviation Glossaries

AGL
Above Ground Level Used in reference to altitude, e.g. 5000 ft AGL - see also: MSL (Mean Sea Level)

airspeed
The speed of an aircraft relative to its surrounding air mass - see also: CAS; IAS; TAS

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 inches of Hg)

AOA (Angle Of Attack)
The angle between the chord line of the wing of an aircraft and the relative wind

approach speed
The recommended speed contained in aircraft manuals used by pilots when making an approach to landing. This speed will vary for different segments of an approach as well as for aircraft weight and configuration

apron
A defined area on an airport or heliport intended to accommodate aircraft for purposes of loading or unloading passengers or cargo, refueling, parking, or maintenance

CAS (Calibrated AirSpeed)
The indicated airspeed of an aircraft, corrected for position and instrument error Calibrated airspeed is equal to true airspeed in standard atmosphere at sea level

chord line
A line drawn from the leading edge of the wing to the trailing edge

contrail
Streaks of condensed water vapor created in the air by aircraft flying at high altitudes

control inputs
The controlling influences a pilot exerts on an aircraft's control surfaces

coordinated turn
A combination of control inputs that cause a maximally efficient turn

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deadstick
Flying without the aid of engine power

dihedral
The upward angle of the airplane's wings with respect to the horizontal

directional stability
The tendency of an aircraft to keep flying the direction it's pointed

dirty; dirty up
Extension of gear, hook, flaps, etc. for slow speed flight or landing

distress
A condition of being threatened by serious and/or imminent danger and of requiring immediate assistance

ditch
To land safely somewhere other than a runway

divert
To change from a scheduled landing base to an alternate airfield

drag
Force created by an airfoil moving through atmosphere, opposite to the direction of motion

ETA
Estimated Time of Arrival. The time the flight is estimated to arrive at its destination

expedite
Used when prompt compliance is required to avoid the development of an imminent situation

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FARs
Federal Aviation Regulations. The laws under which airmen in the US fly

FBO (Fixed Base Operator)
The small but important building near the ramp and runways of a small airport, from which airfield activity is coordinated

final
Used to mean an aircraft is on proper heading, descent rate, airspeed, and altitude during runway approach prior to landing, or to a target prior to weapons release

flare
The maneuver performed moments before landing in which the nose of an aircraft is pitched up to minimize the touchdown descent rate. Also ensures that the main landing gear touches before the nose wheel in tricycle geared aircraft

FPM
Feet Per Minute. Unit of measure, used for ROC (Rate of Descent) or sometimes speed

ground speed
The speed of an aircraft relative to the surface of the earth

IAS (Indicated AirSpeed)
The speed of an aircraft as shown on its pitot static airspeed indicator calibrated to reflect standard atmosphere adiabatic compressible flow at sea level uncorrected for airspeed system errors.

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IFR
Instrument Flight Rules. Weather conditions too poor for flight under VFR. Instrument Navigation Equipment and IR (Instrument Rating) by pilot required to fly under these conditions

ILS
Intrument Landing System. A precision instrument approach system, generally used to land at fields experiencing weather

indicated altitude
The altitude as shown by an altimeter

INS (Inertial Navigation System)
A totally self-contained system which requires no information from outside references. Provides aircraft position and navigation information in response to signals resulting from inertial effects on components within the system

jet stream
A migrating stream of high-speed winds present at high altitudes

KIAS
Knots Indicated Air Speed. IAS, in knots.

knot
One nautical mile (nm) per hour, which is about 1.15 stature miles or 1,85 kilometer per hour.

KTAS
Knots True Air Speed. TAS, in knots

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lateral axis
The axis about which an aircraft pitches, extending out along each wing.

lateral stability
Stability about an airplane's longitudinal (nose to tail) axis

lift
Force created by an airfoil moving through atmosphere, perpendicular to the direction of motion

load factor
The ratio of a specified load to the total weight of the aircraft. The specified load is expressed in terms of any of the following: aerodynamic forces, inertia forces, or ground or water reactions

logbook
A pilot's record of his flying achievements, including flight time, takeoffs, landings, and maneuvers mastered

longitudinal axis
The axis about which an aircraft rolls, extending from nose to tail

longitudinal stability
The characteristic of returning to the trimmed angle of attack after a displacement

Mayday
The international radiotelephony distress signal. When repeated three times, it indicates imminent and grave danger and that immediate assistance is requested. (It originally comes from the French words: m'aider, which means: 'to help me')

MCA
Minimum Controllable Airspeed. The speed below which your control surfaces do not generate sufficient lift to control the aircraft

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MSL (Mean Sea Level)
The average height of the surface of the sea for all stafes of tide; used as a reference for elevations throughout the U.S

N1
The rotational speed of the low-pressure compressor in a dual-spool gas turbine engine

N2
The rotational speed of the high-pressure compressor in a dual-spool gas turbine engine.

NM
Nautical Miles. One nautical mile = 1.15 statute miles = 6,076 feet = 1.85 kilometers

Pan-Pan
The international radio-telephony urgency signal. When repeated three times, indicates uncertainty or alert followed by the nature of the urgency

PIC
Pilot In Command. The pilot responsible for the operation and safety of an aircraft during flight time

pilotage
Navigation by visual reference to landmarks

pitch
The angle of the airplane's longitudinal axis relative to horizontal

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ramp
An airfield parking lot for aircraft

redline
For a given airplane, the airspeed above which it is unsafe to fly. Redlining the plane may over stress or even damage structural elements in the plane

ROC
Rate Of Climb. The speed at which an aircraft is gaining (or losing) altitude, usually measured in hundreds or thousands of FPM

roll
To change the angle of the plane's wings relative to horizontal; also, any maneuver in which the aircraft attains every roll attitude

RPMs
Rotations Per Minute. A unit of measure for such things as engine speed

standard rate turn
A turn of three degrees compass heading per second

TAS
True AirSpeed. The airspeed of an aircraft relative to undisturbed air

taxi
The movement of an airplane under its own power on the surface of an airport

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taxiway
A road leading from the airplane parking area to the runway; always marked with yellow lines

tower
A terminal facility that uses air/ground communications, visual signaling, and other devices to provide ATC services to aircraft operating in the vicinity of an airport or on the movement area

traffic pattern
The traffic flow that is prescribed for aircraft landing at, taxiing on, or taking off from, an airfield

trim
To adjust an aircraft's trim tabs and thereby relieve the pressure required on the controls to keep the nose in the desired position

V(x)
Speed for best angle of climb

V(y)
Speed for best rate of climb

waypoint
A predetermined geographical position used for route/instrument approach definition, or progress reporting purposes, that is defined relative to a VORTAC station or in terms of latitude/longitude coordinates

yaw
The angle of the plane's longitudinal axis relative to its direction of motion

yaw axis
The imaginary vertical axis about which an aircraft yaws

ZULU
Greenwich Mean Time, also known as Universal Coordinated Time

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