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Basic Aviation Terms
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adverse yaw
Yaw generated when the ailerons are used. The lifting wing generates more
drag, causing the plane to yaw toward it.
AGL
Above Ground Level. Used in reference to altitude, e.g. 5000 ft AGL. See also
MSL.
ailerons
Hinged portions of the trailing edges of a wing which can change the wing's
lifting properties.
AIM (Airman's Information Manual)
A primary FAA publication whose purpose is to instruct airmen about operating
in the US airspace system.
airspeed
The speed of an aircraft relative to its surrounding air mass. See: calibrated
airspeed; indicated airspeed; true airspeed.
airspeed indicator
An onboard instrument which registers velocity through the air, in miles per
hour or in knots.
altimeter
An onboard instrument which senses air pressure in order to gauge altitude.
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.
ATC
Air Traffic Control. A service operated by appropriate authority to promote
the safe, orderly and expeditious flow of air traffic.
attitude indicator; artificial horizon
A vacuum powered instrument which displays pitch and roll movement about the
lateral and longitudinal axes.
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.
ceiling
The height above the earth's surface of the lowest layer of clouds or obscuring
phenomena, under which fighter-bombers can visually work a target, i.e. a
200-foot ceiling would be quite dangerous. Or, in reference to aircraft performance,
the maximum altitude an aircraft is able to reach and maintain.
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.
control surfaces
The moving, pilot-controllable parts of the air-frame, including flaps, ailerons,
rudders and elevators.
coordinated turn
A combination of control inputs that cause a maximally efficient turn.
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 its 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.
elevator
Hinged portion of the horizontal stabilizer, which adds or subtracts lift
from the tail, changing the pitch attitude of the aircraft.
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.
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.
flaps
Hinged portions of the wing that act together to increase the lift characteristics
of the wing. Most often used to allow slower landings, and shorter takeoffs.
Not present in most aerobatic aircraft.
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.
flightline
Where aircraft are parked between missions.
FPM
Feet Per Minute. Unit of measure, used for ROC or sometimes speed.
fuselage
The central part of an aircraft, which besides being a common attachment point
for other major components also contains the cockpit/cabin, avionics, and
any cargo space.
gear
Landing gear, the undercarriage and wheels of an aircraft.
ground speed
The speed of an aircraft relative to the surface of the earth.
horizontal stabilizer
The horizontal section of the tail, which provides downward lift to balance
the weight of the nose.
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.
IFR
Instrument Flight Rules. Weather conditions too poor for flight under VFR.
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 per hour, which is about 1.15 stature miles per hour.
KTAS
Knots True AirSpeed. TAS, in knots.
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.
MCA
Minimum Controllable Airspeed. The speed below which your control surfaces
do not generate sufficient lift to control the aircraft.
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.
NM
Nautical Miles. One nautical mile = 1.15 statute miles = 6,080 feet.
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.
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.
rudder
A hinged, movable section of the vertical stabilizer used to control the aircraft's
yaw. Also used as a verb, meaning to angle the rudder in a particular direction.
standard rate turn
A turn of three degrees compass heading per second.
stick
A control in the cockpit which controls the elevators (forward/back axis)
and the ailerons (left/right axis).
tachometer
An onboard instrument which gauges engine speed, in RPMs.
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.
taxiway
A road leading from the airplane parking area to the runway; always marked
with yellow lines.
throttle
The control in the cockpit which controls engine output.
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.
transponder
A receiver/transmitter which will generate a reply signal upon proper interrogation;
the interrogation and reply being on different frequencies.
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.
vertical stabilizer
The vertical section of the tail, which helps keep the airplane aligned with
its direction of motion.
VSI (Vertical Speed Indicator)
An onboard instrument which gauges rate of climb or descent, in feet per minute.
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.