Aviation Dictionary

On this page you will find a searchable and comprehensive alphabetical list of aviation terms. You can help us make it the most comprehensive list in the world. If we have missed anything, click on the ‘send us your word’ button to send us your word, acronym or definition and we will consider adding it to our dictionary.

Aviation Dictionary: T

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TA Traffic advisory
TAF Terminal aerodrome forecast. Issued 1 hour before validity and are valid for 24 hrs. Issued 4 times per day
Tailwind The wind direction that is coming from behind the aircraft and moving in the same direction as the aircraft. This increases the aircrafts groundspeed.
Takeoff Distance The total distance it takes for the aircraft to start rolling, to the point of 50 ft in height.
TAS True air speed
TAT Total air temperature
Taxi Any time the aircraft is moving under its own power on the ground. Directional control is achieved by using the rudder pedals while the control column is used to prevent the wind from raising a wing in strong winds.
Taxiway The areas the aircraft is permitted to move between the runway and apron
TCAS Traffic collision avoidance system
TCU Towering Cumulus
TEM Threat error management
Temperature The measure of how hot or cold something is. Temperature can greatly affect the performance of aircraft. The standard sea level temperature is 15 degrees Celsius.
Temporary Hazards Temporary special use airspace that may have some form of hazard to the pilot. These can be found in Supplements or NOTAMS
Terminal A building within the airport where passengers go to depart a flight, or arrive from a flight which can be made up of several gates where the aircraft can park
TGT Turbine gas temperature
Thermosphere The fourth layer in the earth's atmosphere which lies between the mesosphere and exosphere.
THP Thrust horsepower
Threshold The beginning portion of the runway which is useable for landing
Throttle Lever Also referred to as a Thrust lever or Power lever and is the primary way a pilot controls the amount of fuel that is supplied to the engine.
Thrust A force that opposes drag and is created with engine power. If thrust is more than drag, the airspeed will increase and if it is less than drag then the airspeed will decrease.
Thrust Lever Also referred to as a Throttle lever or Power lever and is the primary way a pilot controls the amount of fuel that is supplied to the engine.
Thunderstorm A storm which is extremely hazardous for aircraft. Severe turbulence is associated with the massive Cumulonimbus cloud, both inside the cloud and below it. Severe icing can be experienced within the cloud as well as hail, which can damage an aircraft.
TIT Turbine inlet temperature
TMG Track made good
TODA Take off distance available
TODR Take off distance required
TOEFL CBT Test of English as a foreign language computer-based test
TOEFL IBT Test of English as a foreign language internet-based test
TOEFL PB Test of English as a foreign language paper-based test
TOEIC Test of English for international communication
Torque A force that attempts to rotate the aircraft, rather than the propeller. This force is noticed on take-off in a single, piston engine aircraft when throttle is increased. You will notice that the aircraft begins yawing and the correct rudder input needs to be applied to maintain centreline
Touch and Go Normally only done while training in the circuit, this is the process of conducting a normal landing, followed by a normal take-off, without stopping in between.
TR Track
Track The path over the ground that the aircraft is flying. This can vary to the aircrafts heading based on the direction of the wind
Traffic Any other aircraft within your vicinity
Transition Altitude (TA) This is the altitude where aircraft switch between using local or area QNH settings to Flight levels using the ISA setting of 1013 hPa
Transition Level The lowest flight level available for use above the transition altitude. This layer will differ between countries.
Trailing Edge The rear edge of the wing
Transponder A transponder is a piece of radio equipment in the aircraft that picks up and automatically responds to an incoming signal. Also the pilot can use to  input various codes which ATC can view and track. The code that the pilot inputs is either a generic code , given directly from ATC or is the standard emergency codes if required
Transponder Code The four digit code inserted into the transponder.
Trend A forecast which is attached to Metar Auto reports. A trend will supersede a TAF
Trim Most often referred to when ‘trimming’ the aircraft using a trim wheel inside the aircraft. In smaller aircraft, a movable trim tab is located on the elevator and can be manually adjusted in flight to balance out small pitching forces. There can also be a fixed trim tab, normally on the rudder which can only be adjusted on the ground. In larger aircraft, the rudder will also have a movable trim tab. 
Tri-Plane An aircraft with three sets of wings, stacked on top of each other.
Troposphere The first layer closest to the earth which has the majority of the atmosphere’s mass. It is wider at the equator than it is at the poles.
True North The geographic North Pole which is determined by an imaginary line drawn through the Earth to find the Northernmost point. It is not in the same position as Magnetic North.
TS Thunderstorm
TTF Trend type forecast
Turbulence This is the ‘bumpiness’ that is experienced during a flight. This can be caused by a number of different sources and can range from light to severe. Different forms of turbulence are; Mechanical turbulence, Wind-shear turbulence, Convective turbulence and Wake turbulence.
Turns Are controlled by a co-ordinated use of the ailerons and the rudder. As a turn begins, the weight vector is no longer directly opposite to the weight vector and we begin to lose altitude, so some backpressure (slight pitch up) needs to be applied to maintain altitude.
Turn & Slip Indicator A gyroscopic instrument which measures the rate at which the aircraft turns as well as the direction that it is turning and gives an indication whether the turn is a balanced turn.
TWS Take off warning system

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