Aeronautical Terms beginning with T
TA
Traffic Advisory
TAC
Terminal Area Chart
TACAN
Tactical Air Navigation Aid. An ultra-high frequency electronic rho-theta air navigation aid which provides suitably equipped aircraft with a continuous indication of bearing and distance to the TACAN station.
TAF
Terminal Aerodrome Forecast
Tailwind
Any wind more than 90 degrees to the longitudinal axis of the runway. The magnetic direction of the runway shall be used as the basis for determining the longitudinal axis.
Takeoff Area
Landing Area.
Takeoff distance
The distance required to complete an all-engines operative takeoff to the 35-foot height. It must be at least 15 percent less than the distance required for a one-engine inoperative engine takeoff. This distance is not normally a limiting factor as it is usually less than the one-engine inoperative takeoff distance.
Takeoff power
(1) With respect to reciprocating engines, the brake horsepower that is developed under standard sea level conditions, and under the maximum conditions of crankshaft rotational speed and engine manifold pressure approved for the normal takeoff, and limited in continuous use to the period of time shown in the approved engine specification; and
(2) With respect to turbine engines, the brake horsepower that is developed under static conditions at a specified altitude and atmospheric temperature, and under the maximum conditions of rotor shaft rotational speed and gas temperature approved for the normal takeoff, and limited in continuous use to the period of time shown in the approved engine specification.
Takeoff Roll (Ground Roll)
The total distance required for an aircraft to become airborne.
Target
The indication shown on an analog display resulting from a primary radar return or a radar beacon reply.
Tarmac Delay
The holding of an aircraft on the ground either before departure or after landing with no opportunity for its passengers to deplane.
TAS
True Airspeed.
TAWS
Terrain Awareness and Warning System.
Taxi
The movement of an airplane under its own power on the surface of an airport (14 CFR Section 135.100 [Note]). Also, it describes the surface movement of helicopters equipped with wheels.
Taxi Patterns
Patterns established to illustrate the desired flow of ground traffic for the different runways or airport areas available for use.
Taxiway Lights
Omnidirectional lights that outline the edges of the taxiway and are blue in color.
Taxiway Turnoff Lights
Flush lights which emit a steady green color.
TCAS
A Traffic Alert and Collision Avoidance System.
TD
Time Difference
TDLS
Tower Data Link System
TDWR
Terminal Doppler Weather Radar
TDZL
Touchdown Zone Lights
Temporary flight restriction (TFR)
Restriction to flight imposed in order to:
1. Protect persons and property in the air or on the surface from an existing or imminent flight associated hazard;
2. Provide a safe environment for the operation of disaster relief aircraft;
3. Prevent an unsafe congestion of sightseeing aircraft above an incident;
4. Protect the President, Vice President, or other public figures; and,
5. Provide a safe environment for space agency operations.
Pilots are expected to check appropriate NOTAMs during flight planning when conducting flight in an area where a temporary flight restriction is in effect.
Terminal Area
A general term used to describe airspace in which approach control service or airport traffic control service is provided.
Terminal Radar Service Area
Airspace surrounding designated airports wherein ATC provides radar vectoring, sequencing, and separation on a full-time basis for all IFR and participating VFR aircraft. The AIM contains an explanation of TRSA. TRSAs are depicted on VFR aeronautical charts. Pilot participation is urged but is not mandatory.
Terminal VFR Radar Service
A national program instituted to extend the terminal radar services provided instrument flight rules (IFR) aircraft to visual flight rules (VFR) aircraft. The program is divided into four types service referred to as basic radar service, terminal radar service area (TRSA) service, Class B service and Class C service. The type of service provided at a particular location is contained in the Airport/Facility Directory.
Terrain awareness and warning system (TAWS)
A timed-based system that provides information concerning potential hazards with fixed objects by using GPS positioning and a database of terrain and obstructions to provide true predictability of the upcoming terrain and obstacles.
Terrain/Obstruction Alert
A safety alert issued by ATC to aircraft under their control if ATC is aware the aircraft is at an altitude which, in the controller’s judgment, places the aircraft in unsafe proximity to terrain/obstructions; e.g., “Low Altitude Alert, check your altitude immediately.”
Tetrahedron
A large, triangular-shaped, kite-like object installed near the runway. Tetrahedrons are mounted on a pivot and are free to swing with the wind to show the pilot the direction of the wind as an aid in takeoffs and landings.
TFC
Traffic
TFR
Temporary Flight Restriction.
That Is Correct
The understanding you have is right.
THL
Takeoff Hold Lights
Three-Hour Tarmac Rule
Rule that relates to Department of Transportation (DOT) requirements placed on airlines when tarmac delays are anticipated to reach 3 hours.
Threshold
The beginning of that portion of the runway usable for landing.
Threshold Lights
Fixed green lights arranged symmetrically left and right of the runway centerline, identifying the runway threshold.
Thrust (aerodynamic force)
The forward aerodynamic force produced by a propeller, fan, or turbojet engine as it forces a mass of air to the rear, behind the aircraft.
Thrust line
An imaginary line passing through the center of the propeller hub, perpendicular to the plane of the propeller rotation.
TIBS
Telephone Information Briefing Service - Discontinued in the CONUS in September 2018 and in Alaska on Jan 1, 2020.
Timed turn
A turn in which the clock and the turn coordinator are used to change heading a definite number of degrees in a given time.
TIS
Traffic Information Service
Torque
1. A resistance to turning or twisting.
2. Forces that produce a twisting or rotating motion.
3. In an airplane, the tendency of the aircraft to turn (roll) in the opposite direction of rotation of the engine and propeller.
Total Drag
The sum of the parasite and induced drag.
Touch-And-Go
An operation by an aircraft that lands and departs on a runway without stopping or exiting the runway.
Touch-And-Go Landing
Touch-And-Go.
Touchdown
A. The point at which an aircraft first makes contact with the landing surface.
B. Concerning a precision radar approach (PAR), it is the point where the glide path intercepts the landing surface.
Touchdown Zone Lighting
Two rows of transverse light bars located symmetrically about the runway centerline normally at 100 foot intervals. The basic system extends 3,000 feet along the runway.
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. Authorizes aircraft to land or takeoff at the airport controlled by the tower or to transit the Class D airspace area regardless of flight plan or weather conditions (IFR or VFR). A tower may also provide approach control services (radar or nonradar).
Trace Icing
Ice becomes perceptible. Rate of accumulation is slightly greater than the rate of sublimation. Deicing/anti-icing equipment is not utilized unless encountered for an extended period of time (over 1 hour).
Track
The actual path made over the ground in flight.
Tracking
Flying a heading that will maintain the desired track to or from the station regardless of crosswind conditions.
TRACON
Terminal Radar Control Facility. A terminal ATC facility that uses radar and nonradar capabilities to provide approach control services to aircraft arriving, departing, or transiting airspace controlled by the facility.
Traffic
A. A term used by a controller to transfer radar identification of an aircraft to another controller for the purpose of coordinating separation action. Traffic is normally issued:
1. In response to a handoff or point out,
2. In anticipation of a handoff or point out, or
3. In conjunction with a request for control of an aircraft.
B. A term used by ATC to refer to one or more aircraft.
Traffic Advisories
Advisories issued to alert pilots to other known or observed air traffic which may be in such proximity to the position or intended route of flight of their aircraft to warrant their attention. Such advisories may be based on: a. Visual observation. b. Observation of radar identified and nonidentified aircraft targets on an ATC radar display, or c. Verbal reports from pilots or other facilities. Note 1: The word “traffic” followed by additional information, if known, is used to provide such advisories; e.g., “Traffic, 2 o’clock, one zero miles, southbound, eight thousand.” Note 2: Traffic advisory service will be provided to the extent possible depending on higher priority duties of the controller or other limitations; e.g., radar limitations, volume of traffic, frequency congestion, or controller workload. Radar/ nonradar traffic advisories do not relieve the pilot of his/her responsibility to see and avoid other aircraft. Pilots are cautioned that there are many times when the controller is not able to give traffic advisories concerning all traffic in the aircraft’s proximity; in other words, when a pilot requests or is receiving traffic advisories, he/she should not assume that all traffic will be issued.
Traffic Alert
(aircraft call sign), TURN (left/right) IMMEDIATELY, (climb/descend) AND MAINTAIN (altitude).
Traffic In Sight
Used by pilots to inform a controller that previously issued traffic is in sight.
Traffic Information
Traffic Advisories.
Traffic information service (TIS)
A ground-based service providing information to the flight deck via data link using the S-mode transponder and altitude encoder to improve the safety and efficiency of “see and avoid” flight through an automatic display that informs the pilot of nearby traffic.
Traffic No Factor
Indicates that the traffic described in a previously issued traffic advisory is no factor.
Traffic No Longer Observed
Indicates that the traffic described in a previously issued traffic advisory is no longer depicted on radar, but may still be a factor.
Traffic Pattern
The traffic flow that is prescribed for aircraft landing at, taxiing on, or taking off from an airport. The components of a typical traffic pattern are upwind leg, crosswind leg, downwind leg, base leg, and final approach.
Trailing edge
The portion of the airfoil where the airflow over the upper surface rejoins the lower surface airflow.
Transfer Of Control
That action whereby the responsibility for the separation of an aircraft is transferred from one controller to another.
Transition
The general term that describes the change from one phase of flight or flight condition to another; e.g., transition from en route flight to the approach or transition from instrument flight to visual flight.
Transition training
An instructional program designed to familiarize and qualify a pilot to fly types of aircraft not previously flown, such as tail wheel aircraft, high performance aircraft, and aircraft capable of flying at high altitudes.
Transmitting In The Blind
A transmission from one station to other stations in circumstances where two-way communication cannot be established, but where it is believed that the called stations may be able to receive the transmission.
Transponder
The airborne radar beacon receiver/transmitter portion of the Air Traffic Control Radar Beacon System (ATCRBS) which automatically receives radio signals from interrogators on the ground, and selectively replies with a specific reply pulse or pulse group only to those interrogations being received on the mode to which it is set to respond.
Transponder code
One of 4,096 four-digit discrete codes ATC assigns to distinguish between aircraft.
Transponder Observed
Phraseology used to inform a VFR pilot the aircraft’s assigned beacon code and position have been observed. Specifically, this term conveys to a VFR pilot the transponder reply has been observed and its position correlated for transit through the designated area.
Trend
Immediate indication of the direction of aircraft movement, as shown on instruments.
Tricycle gear
Landing gear employing a third wheel located on the nose of the aircraft.
Trim
To adjust the aerodynamic forces on the control surfaces so that the aircraft maintains the set attitude without any control input.
Trim tab
A small auxiliary hinged portion of a movable control surface that can be adjusted during flight to a position resulting in a balance of control forces.
TRSA
Terminal Radar Service Area
TRSA Service
This service provides, in addition to basic radar service, sequencing of all IFR and participating VFR aircraft to the primary airport and separation between all participating VFR aircraft. The purpose of this service is to provide separation between all participating VFR aircraft and all IFR aircraft operating within the area defined as a TRSA.
True airspeed
Actual airspeed, determined by applying a correction for pressure altitude and temperature to the CAS.
True Altitude
The vertical distance of the airplane above sea level—the actual altitude. It is often expressed as feet above mean sea level (MSL). Airport, terrain, and obstacle elevations on aeronautical charts are true altitudes.
True Course
A predetermined desired course direction to be followed (measured in degrees from true north).
TSA
Transportation Security Administration (TSA) protects the nation’s transportation systems to ensure freedom of movement for people and commerce.
TSD
Traffic Situation Display. A tool used by Traffic Management Specialists to monitor the position of air traffic and to determine the traffic demand on airports and sectors.
TSO
Technical Standard Order.
TSTMS
Thunderstorms
Turbojet Aircraft
An aircraft having a jet engine in which the energy of the jet operates a turbine which in turn operates the air compressor.
Turboprop Aircraft
An aircraft having a jet engine in which the energy of the jet operates a turbine which drives the propeller.
Turn Anticipation
(maneuver anticipation).
Turn coordinator
A rate gyro that senses both roll and yaw due to the gimbal being canted. Has largely replaced the turn-and-slip indicator in modern aircraft.
Turn-and-slip indicator
A flight instrument consisting of a rate gyro to indicate the rate of yaw and a curved glass inclinometer to indicate the relationship between gravity and centrifugal force. The turn-and-slip indicator indicates the relationship between angle of bank and rate of yaw. Also called a turn-and-bank indicator.
Turning Error
One of the errors inherent in a magnetic compass caused by the dip compensating weight. It shows up only on turns to or from northerly headings in the Northern Hemisphere and southerly headings in the Southern Hemisphere. Turning error causes the compass to lead turns to the north or south and lag turns away from the north or south.
TVOR
Very High Frequency Terminal Omnirange Station.
TWEB
Transcribed Weather Broadcast - Discontinued in the CONUS in September 2018 and in Alaska on Jan 1, 2020.
TWIB
Terminal Weather Information for Pilots System
Two-Way Radio Communications Failure
Lost Communications.
Type
(1) As used with respect to the certification, ratings, privileges, and limitations of airmen, a specific make and basic model of aircraft, including modifications thereto that do not change its handling or flight characteristics. Examples include: DC–7, 1049, and F–27; and
(2) As used with respect to the certification of aircraft, those aircraft which are similar in design. Examples include: DC–7 and DC–7C; 1049G and 1049H; and F–27 and F–27F.
(3) As used with respect to the certification of aircraft engines, those engines which are similar in design. For example, JT8D and JT8D–7 are engines of the same type, and JT9D–3A and JT9D–7 are engines of the same type.
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