Aeronautical Terms beginning with T
T-Tail
An aircraft with the horizontal stabilizer mounted on the top of the vertical stabilizer, forming a T.
Tacan-Only Aircraft
An aircraft, normally military, possessing TACAN with DME but no VOR navigational system capability. Clearances must specify TACAN or VORTAC fixes and approaches.
Tactical Air Navigation
An ultra-high frequency electronic rho-theta air navigation aid which provides suitably equipped aircraft a continuous indication of bearing and distance to the TACAN station.
Tactical air navigation (TACAN)
An electronic navigation system used by military aircraft, providing both distance and direction information.
Tailwheel Aircraft
See Conventional landing Gear.
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.
Take-Off Distance Available [ICAO]
The length of the take-off run available plus the length of the clearway, if provided.
Take-Off Run Available [ICAO]
The length of runway declared available and suitable for the ground run of an aeroplane take-off.
Takeoff Area
Landing Area.
Takeoff decision speed (V1)
Per 14 CFR section 23.51: “the calibrated airspeed on the ground at which, as a result of engine failure or other reasons, the pilot assumed to have made a decision to continue or discontinue the takeoff.”.
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 Distance Available (TODA)
ICAO defines TODA as the length of the takeoff runway available plus the length of the clearway, if provided.
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.
Takeoff Run Available (TORA)
The runway length declared available and suitable for the ground run of an airplane taking off.
Takeoff Runway Available (TORA)
ICAO defines TORA as the length of runway declared available and suitable for the ground run of an aeroplane takeoff.
Takeoff safety speed
A referenced airspeed obtained after lift-off at which the required one-engine-inoperative climb performance can be achieved.
Takeoff safety speed (V2)
Per 14 CFR part 1: “A referenced airspeed obtained after lift-off at which the required one-engine-inoperative climb performance can be achieved.”.
Takeoff thrust
With respect to turbine engines, the jet thrust that is developed under static conditions at a specific altitude and atmospheric temperature under the maximum conditions of rotorshaft 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 Weight
The weight of an aircraft just before beginning the takeoff roll. It is the ramp weight less the weight of the fuel burned during start and taxi.
Tandem wing configuration
A configuration having two wings of similar span, mounted in tandem.
Tangent Point (TP)
The point on the VOR/DME RNAV route centerline from which a line perpendicular to the route centerline would pass through the reference facility.
Tare Weight
The weight of any chocks or devices that are used to hold an aircraft on the scales when it is weighed. The tare weight must be subtracted from the scale reading to get the net weight of the aircraft.
Target
In radar, any of the many types of objects detected by radar.
Target Resolution
A process to ensure that correlated radar targets do not touch. Target resolution must be applied as follows: a. Between the edges of two primary targets or the edges of the ASR-9/11 primary target symbol. b. Between the end of the beacon control slash and the edge of a primary target. c. Between the ends of two beacon control slashes. Note 1: Mandatory traffic advisories and safety alerts must be issued when this procedure is used. Note 2: This procedure must not be used when utilizing mosaic radar systems or multi-sensor mode.
Target Reverser
A thrust reverser in a jet engine in which clamshell doors swivel from the stowed position at the engine tailpipe to block all of the outflow and redirect some component of the thrust forward.
Target Symbol
A computer-generated indication shown on a radar display resulting from a primary radar return or a radar beacon reply.
Target [ICAO]
In radar: a. Generally, any discrete object which reflects or retransmits energy back to the radar equipment. b. Specifically, an object of radar search or surveillance.
Tarmac Delay
The holding of an aircraft on the ground either before departure or after landing with no opportunity for its passengers to deplane.
Tarmac Delay Aircraft
An aircraft whose pilot-in-command has requested to taxi to the ramp, gate, or alternate deplaning area to comply with the Three-hour Tarmac Rule.
Tarmac Delay Request
A request by the pilot-in-command to taxi to the ramp, gate, or alternate deplaning location to comply with the Three-hour Tarmac Rule.
Task
Knowledge area, flight procedure, or maneuver within an area of operation in a practical test standard.
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.
Taxonomy of educational objectives
A systematic classification scheme for sorting learning outcomes into three broad categories (cognitive, affective, and psychomotor) and ranking the desired outcomes in a developmental hierarchy from least complex to most complex.
Teaching
Instructing, training, or imparting knowledge or skill; the profession of someone who teaches.
Teaching lecture
An oral presentation that is directed toward desired learning outcomes. Some student participation is allowed.
Technique
The manner in which procedures are executed.
Telephone Information Briefing Service
A continuous telephone recording of meteorological and/or aeronautical information. Discontinued in the CONUS in September 2018 and in Alaska on Jan 1, 2020.
Telephone information briefing service (TIBS)
Telephone recording of area and/or route meteorological briefings, airspace procedures, and special aviation-oriented announcements. Discontinued in the CONUS in September 2018 and in Alaska on Jan 1, 2020.
Telling-and-doing technique
A technique of flight instruction that consists of the instructor first telling the student about a new procedure and then demonstrating it. This is followed by the student telling and the instructor doing. Third, the student explains the new procedure while doing it. Last, the instructor evaluates while the student performs the procedure.
Temperature
In general, the degree of hotness or coldness as measured on some definite temperature scale by means of any of various types of thermometers.
Temperature inversion
Inversion. An increase in temperature with height-a reversal of the normal decrease with height in the troposphere; may also be applied to other meteorological properties.
Temporary Ballast
Weights that can be carried in a cargo compartment of an aircraft to move the location of CG for a specific flight condition. Temporary ballast must be removed when the aircraft is weighed.
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.
Tension
Maintaining an excessively strong grip on the control column, usually resulting in an overcontrolled situation.
Tentative Calculated Landing Time
A projected time calculated for adapted vertex for each arrival aircraft based upon runway configuration, airport acceptance rate, airport arrival delay period, and other metered arrival aircraft. This time is either the VTA of the aircraft or the TCLT/ACLT of the previous aircraft plus the AAI, whichever is later. This time will be updated in response to an aircraft’s progress and its current relationship to other arrivals.
Terminal aerodrome forecast (TAF)
A report established for the 5 statute mile radius around an airport. Utilizes the same descriptors and abbreviations as the METAR report.
Terminal Area
A general term used to describe airspace in which approach control service or airport traffic control service is provided.
Terminal Area Facility
A facility providing air traffic control service for arriving and departing IFR, VFR, Special VFR, and on occasion en route aircraft.
Terminal Arrival Area (TAA)
TAAs are the method by which aircraft are transitioned from the RNAV en route structure to the terminal area with minimal ATC interaction. The TAA consists of a designated volume of airspace designed to allow aircraft to enter a protected area, offering guaranteed obstacle clearance where the initial approach course is intercepted based on the location of the aircraft relative to the airport.
Terminal Automation Systems (TAS)
TAS is used to identify the numerous automated tracking systems including ARTS IIE, ARTS IIIA, ARTS IIIE, STARS, and MEARTS.
Terminal Data Link System (TDLS)
A system that provides Digital Automatic Terminal Information Service (D-ATIS) both on a specified radio frequency and also, for subscribers, in a text message via data link to the cockpit or to a gate printer. TDLS also provides Pre-departure Clearances (PDC), at selected airports, to subscribers, through a service provider, in text to the cockpit or to a gate printer. In addition, TDLS will emulate the Flight Data Input/Output (FDIO) information within the control tower.
Terminal instrument approach procedure (TERP)
Prescribes standardized methods for use in designing instrument flight procedures.
Terminal Instrument Approach Procedure (TERP).
Prescribes standardized methods for use in designing instrument flight procedures.
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 radar service areas (TRSA)
Areas where participating pilots can receive additional radar services. The purpose of the service is to provide separation between all IFR operations and participating VFR aircraft.
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.
Terminal-Very High Frequency Omnidirectional Range Station
A very high frequency terminal omnirange station located on or near an airport and used as an approach aid.
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 Awareness Warning System (TAWS)
An on-board, terrain proximity alerting system providing the aircrew `Low Altitude warnings’ to allow immediate pilot action.
Terrain Following
The flight of a military aircraft maintaining a constant AGL altitude above the terrain or the highest obstruction. The altitude of the aircraft will constantly change with the varying terrain and/or obstruction.
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.”
Terrestrial radiation
The total infrared radiation emitted by the Earth and its atmosphere.
Test
A set of questions, problems, or exercises for determining whether a person has a particular knowledge or skill.
Test item
A question, problem, or exercise that measures a single objective and requires a single response.
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.
That Is Correct
The understanding you have is right.
Theodolite
An optical instrument which, in meteorology, is used principally to observe the motion of a pilot balloon.
Thermograph
A continuous-recording thermometer.
Thermometer
An instrument for measuring temperature.
Thermosphere
The last layer of the atmosphere that begins above the mesosphere and gradually fades away into space.
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 the part of the runway usable for landing.
Threshold Crossing Height
The theoretical height above the runway threshold at which the aircraft’s glideslope antenna would be if the aircraft maintains the trajectory established by the mean ILS glideslope or MLS glidepath.
Threshold crossing height (TCH)
The theoretical height above the runway threshold at which the aircrafts glide slope antenna would be if the aircraft maintains the trajectory established by the mean ILS glide slope or MLS glide path.
Threshold Lights
Airport Lighting.
Throttle
The valve in a carburetor or fuel control unit that determines the amount of fuel-air mixture that is fed to the engine.
Thrust
The force which imparts a change in the velocity of a mass. This force is measured in pounds but has no element of time or rate. The term, thrust required, is generally associated with jet engines. A forward force which propels the airplane through the air.
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.
Thrust Reversers
Devices which redirect the flow of jet exhaust to reverse the direction of thrust.
Thunderstorm
In general, a local storm invariably produced by a cumulonimbus cloud, and always accompanied by lightning and thunder.
Time and opportunity
A perception factor in which learning something is dependent on the student having the time to sense and relate current experiences in context with previous events.
Time and speed table
A table depicted on an instrument approach procedure chart that identifies the distance from the FAF to the MAP, and provides the time required to transit that distance based on various groundspeeds.
Time Group
Four digits representing the hour and minutes from the Coordinated Universal Time (UTC) clock. FAA uses UTC for all operations. The term “ZULU” may be used to denote UTC. The word “local” or the time zone equivalent shall be used to denote local when local time is given during radio and telephone communications. When written, a time zone designator is used to indicate local time; e.g. “0205M” (Mountain). The local time may be based on the 24-hour clock system. The day begins at 0000 and ends at 2359.
Time in service
With respect to maintenance time records, the time from the moment an aircraft leaves the surface of the earth until it touches it at the next point of landing.
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.
Timing
The application of muscular coordination at the proper instant to make flight, and all maneuvers incident thereto, a constant smooth process.
Tire Cord
Woven metal wire laminated into the tire to provide extra strength. A tire showing any cord must be replaced prior to any further flight.
Top of Climb (TOC)
An identifiable waypoint representing the point at which cruise altitude is first reached. TOC is calculated based on your current aircraft altitude, climb speed, and cruise altitude. There can only be one TOC waypoint at a time.
Top of Descent (TOD)
Generally utilized in flight management systems, top of descent is an identifiable waypoint representing the point at which descent is first initiated from cruise altitude. TOD is generally calculated using the destination elevation (if available) and the descent speed schedule.
Torching
The burning of fuel at the end of an exhaust pipe or stack of a reciprocating aircraft engine, the result of an excessive richness in the fuel air mixture.
Tornado (sometimes called cyclone, twister)
A violently rotating column of air, pendant from a cumulonimbus cloud, and nearly always observable as “funnel-shaped.” It is the most destructive of all small-scale atmospheric phenomena.
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.
Torque Meter
An indicator used on some large reciprocating engines or on turboprop engines to indicate the amount of torque the engine is producing.
Torque Sensor
See Torque Meter.
Torquemeter
An instrument used with some of the larger reciprocating engines and turboprop or turboshaft engines to measure the reaction between the propeller reduction gears and the engine case.
Total Drag
The sum of the parasite and induced drag.
Total Estimated Elapsed Time [ICAO]
For IFR flights, the estimated time required from take-off to arrive over that designated point, defined by reference to navigation aids, from which it is intended that an instrument approach procedure will be commenced, or, if no navigation aid is associated with the destination aerodrome, to arrive over the destination aerodrome. For VFR flights, the estimated time required from take-off to arrive over the destination aerodrome.
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 and Lift-Off Area (TLOF)
The TLOF is a load bearing, usually paved area at a heliport where the helicopter is permitted to land. The TLOF can be located at ground or rooftop level, or on an elevated structure. The TLOF is normally centered in the FATO.
Touchdown RVR
The RVR visibility readout values obtained from sensors serving the runway touchdown zone.
Touchdown Zone
The first 3,000 feet of the runway beginning at the threshold. The area is used for determination of Touchdown Zone Elevation in the development of straight-in landing minimums for instrument approaches.
Touchdown Zone Elevation
The highest elevation in the first 3,000 feet of the landing surface. TDZE is indicated on the instrument approach procedure chart when straight-in landing minimums are authorized.
Touchdown Zone Elevation (TDZE)
The highest elevation in the first 3,000 feet of the landing surface.
Touchdown Zone Lighting
Airport Lighting.
Touchdown Zone Lights
Two rows of transverse light bars disposed symmetrically about the runway centerline in the runway touchdown zone.
Touchdown Zone [ICAO]
The portion of a runway, beyond the threshold, where it is intended landing aircraft first contact the runway.
Touchdown [ICAO]
The point where the nominal glide path intercepts the runway. Note: Touchdown as defined above is only a datum and is not necessarily the actual point at which the aircraft will touch 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).
Tower En Route Control (TEC)
The control of IFR en route traffic within delegated airspace between two or more adjacent approach control facilities. This service is designed to expedite air traffic and reduces air traffic control and pilot communication requirements.
Tower En Route Control Service
The control of IFR en route traffic within delegated airspace between two or more adjacent approach control facilities. This service is designed to expedite traffic and reduce control and pilot communication requirements.
Tower To Tower
Tower En Route Control Service.
Tower visibility
Prevailing VIsibility determined from the control tower.
Towering cumulus
A rapidly growing cumulus in which height exceeds width.
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).
Traceable Pressure Standard
The facility station pressure instrument, with certification/calibration traceable to the National Institute of Standards and Technology. Traceable pressure standards may be mercurial barometers, commissioned ASOS/AWSS or dual transducer AWOS, or portable pressure standards or DASI.
Track
The actual path made over the ground in flight.
Track Of Interest (TOI)
Displayed data representing an airborne object that threatens or has the potential to threaten North America or National Security. Indicators may include, but are not limited to: noncompliance with air traffic control instructions or aviation regulations; extended loss of communications; unusual transmissions or unusual flight behavior; unauthorized intrusion into controlled airspace or an ADIZ; noncompliance with issued flight restrictions/security procedures; or unlawful interference with airborne flight crews, up to and including hijack. In certain circumstances, an object may become a TOI based on specific and credible intelligence pertaining to that particular aircraft/object, its passengers, or its cargo.
Track Of Interest Resolution
A TOI will normally be considered resolved when: the aircraft/object is no longer airborne; the aircraft complies with air traffic control instructions, aviation regulations, and/or issued flight restrictions/security procedures; radio contact is re-established and authorized control of the aircraft is verified; the aircraft is intercepted and intent is verified to be nonthreatening/nonhostile; TOI was identified based on specific and credible intelligence that was later determined to be invalid or unreliable; or displayed data is identified and characterized as invalid.
Track [ICAO]
The projection on the earth’s surface of the path of an aircraft, the direction of which path at any point is usually expressed in degrees from North (True, Magnetic, or Grid).
Tracking
Flying a heading that will maintain the desired track to or from the station regardless of crosswind conditions.
Trade winds
Prevailing, almost continuous winds blowing with an easterly component from the subtropical high pressure belts toward the intertropical convergence cone; northeast in the Northern Hemisphere, southeast in the Southern Hemisphere.
Traditional assessment
Written testing, such as multiple choice, matching, true/false, or fill-in-the-blank.
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 Alert And Collision Avoidance System
An airborne collision avoidance system based on radar beacon signals which operates independent of ground-based equipment. TCAS-I generates traffic advisories only. TCAS-II generates traffic advisories, and resolution (collision avoidance) advisories in the vertical plane.
Traffic Alert Collision Avoidance System (TCAS)
An airborne system developed by the FAA that operates independently from the ground-based Air Traffic Control system. Designed to increase flight deck awareness of proximate aircraft and to serve as a “last line of defense” for the prevention of midair collisions.
Traffic Alert Collision Avoidance System (TCAS).
An airborne system developed by the FAA that operates independently from the ground-based Air Traffic Control system. Designed to increase flight deck awareness of proximate aircraft and to serve as a last line of defense for the prevention of mid-air collisions.
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 Information Service-Broadcast (TIS-B)
An air traffic surveillance system that combines all available traffic information on a single display.
Traffic Management Advisor (TMA)
A software suite that helps air traffic controllers to sequence arriving air traffic.
Traffic Management Program Alert
A term used in a Notice to Airmen (NOTAM) issued in conjunction with a special traffic management program to alert pilots to the existence of the program and to refer them to either the Notices to Airmen publication or a special traffic management program advisory message for program details. The contraction TMPA is used in NOTAM text.
Traffic Management Unit
The entity in ARTCCs and designated terminals directly involved in the active management of facility traffic. Usually under the direct supervision of an assistant manager for traffic management.
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.
Traffic Situation Display (TSD)
TSD is a computer system that receives radar track data from all 20 CONUS ARTCCs, organizes this data into a mosaic display, and presents it on a computer screen. The display allows the traffic management coordinator multiple methods of selection and highlighting of individual aircraft or groups of aircraft. The user has the option of superimposing these aircraft positions over any number of background displays. These background options include ARTCC boundaries, any stratum of en route sector boundaries, fixes, airways, military and other special use airspace, airports, and geopolitical boundaries. By using the TSD, a coordinator can monitor any number of traffic situations or the entire systemwide traffic flows.
Trailing Edge
The portion of the airfoil where the airflow over the upper surface rejoins the lower surface airflow.
Training course outline
Within a curriculum, describes the content of a particular course by statement of objectives, descriptions of teaching aids, definition of evaluation criteria, and indication of desired outcome.
Training media
Any physical means that communicates an instructional message to students.
Training syllabus
A step by- step, building block progression of learning with provisions for regular review and evaluations at prescribed stages of learning. The syllabus defines the unit of training, states by objective what the student is expected to accomplish during the unit of training, shows an organized plan for instruction, and dictates the evaluation process for either the unit or stages of learning.
Trajectory
A URET representation of the path an aircraft is predicted to fly based upon a Current Plan or Trial Plan.
Trajectory Modeling
The automated process of calculating a trajectory.
Transcribed Weather Broadcast (TWEB)
Meteorological and aeronautical data recorded on tapes and broadcast over selected NAVAIDs. Generally, the broadcast contains route-oriented data with specially prepared NWS forecasts, inflight advisories, and winds aloft. It also includes selected current information such as weather reports (METAR/SPECI), NOTAMs, and special notices. Discontinued in the CONUS in September 2018 and in Alaska on Jan 1, 2020.
Transfer Of Control
That action whereby the responsibility for the separation of an aircraft is transferred from one controller to another.
Transfer Of Control [ICAO]
Transfer of responsibility for providing air traffic control service.
Transfer of learning
The ability to apply knowledge or procedures learned in one context to new contexts.
Transferring Controller
A controller/facility transferring control of an aircraft to another controller/facility.
Transferring Facility
Transferring Controller.
Transferring Unit/Controller [ICAO]
Air traffic control unit/air traffic controller in the process of transferring the responsibility for providing air traffic control service to an aircraft to the next air traffic control unit/air traffic controller along the route of flight. Note: See definition of accepting unit/controller.
Transition
A published procedure (DP Transition) used to connect the basic DP to one of several en route airways/jet routes, or a published procedure (STAR Transition) used to connect one of several en route airways/jet routes to the basic STAR.
Transition Altitude (QNH)
The altitude in the vicinity of an airport at or below which the vertical position of an aircraft is controlled by reference to altitudes (MSL).
Transition Height (QFE)
Transition height is the height in the vicinity of an airport at or below which the vertical position of an aircraft is expressed in height above the airport reference datum.
Transition Layer
Transition layer is the airspace between the transition altitude and the transition level. Aircraft descending through the transition layer will set altimeters to local station pressure, while departing aircraft climbing through the transition layer will be using standard altimeter setting (QNE) of 29.92 inches of Mercury, 1013.2 millibars, or 1013.2 hectopascals.
Transition Level (QNE)
The lowest flight level available for use above the transition altitude.
Transition Liner
The portion of the combustor that directs the gases into the turbine plenum.
Transition Point
A point at an adapted number of miles from the vertex at which an arrival aircraft would normally commence descent from its en route altitude. This is the first fix adapted on the arrival speed segments.
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.
Transition Waypoint
The waypoint that defines the beginning of a runway or en route transition on an RNAV SID or STAR.
Transitional Airspace
That portion of controlled airspace wherein aircraft change from one phase of flight or flight condition to another.
Transmissometer
An instrument system which shows the transmissivity of light through the atmosphere. Transmissivity may be translated either automatically or manually into visibility and/or runway visual range.
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.
Transonic
At the speed of sound.
Transponder
The airborne portion of the secondary surveillance radar system. The transponder emits a reply when queried by a radar facility.
Transponder code
One of 4,096 four-digit discrete codes ATC assigns to distinguish between aircraft.
Transponder Codes
Codes.
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.
Transponder [ICAO]
A receiver/transmitter which will generate a reply signal upon proper interrogation; the interrogation and reply being on different frequencies.
Trend
Immediate indication of the direction of aircraft movement, as shown on instruments.
Trial Plan
A proposed amendment which utilizes automation to analyze and display potential conflicts along the predicted trajectory of the selected aircraft.
Tricycle Gear
Landing gear employing a third wheel located on the nose of the aircraft.
Trim
Adjusting 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.
Triple Spool Engine
Usually a turbofan engine design where the fan is the N1 compressor, followed by the N2 intermediate compressor, and the N3 high pressure compressor, all of which rotate on separate shafts at different speeds.
Tropical air
An air mass with characteristics developed over low latitudes. Maritime tropical air (mT), the principal type, is produced over the tropical and subtropical seas; very warm and humid. Continental tropical (cT) is produced over subtropical arid regions and is hot and very dry. Compare polar air.
Tropical cyclone
A general term for a cyclone that originates over tropical oceans. By international agreement, tropical cyclones have been classified according to their intensity, as follows: (1) tropical depression-winds up to 34 knots (64 km/h); (2) tropical storm-winds of 35 to 64 knots (65 to 119 km/h); (3) hurricane or typhoon-winds of 65 knots or higher (120 km/h).
Tropical depression
A cyclone that originates over tropical oceans. A tropical depression winds up to 34 knots (64 km/h).
Tropical storm
A cyclone that originates over tropical oceans. A tropical storm has winds of 35 to 64 knots (65 to 119 km/h).
Tropopause
The boundary layer between the troposphere and the mesosphere which acts as a lid to confine most of the water vapor, and the associated weather, to the troposphere.
Troposphere
The layer of the atmosphere extending from the surface to a height of 20,000 to 60,000 feet depending on latitude.
Trough (also called trough line)
In meteorology, an elongated area of relatively low atmospheric pressure; usually associated with and most clearly identified as an area of maximum cyclonic curvature of the wind flow (isobars, contours, or streamlines); compare with ridge.
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 Airspeed (TAS)
Calibrated airspeed corrected for altitude and nonstandard temperature. Because air density decreases with an increase in altitude, an airplane has to be flown faster at higher altitudes to cause the same pressure difference between pitot impact pressure and static pressure. Therefore, for a given calibrated airspeed, true airspeed increases as altitude increases; or for a given true airspeed, calibrated airspeed decreases as altitude increases.
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).
True wind direction
The direction, with respect to true north, from which the wind is blowing.
True-false test item
A test item consisting of a statement followed by an opportunity for the student to determine whether the statement is true or false.
Truss
A fuselage design made up of supporting structural members that resist deformation by applied loads. The truss-type fuselage is constructed of steel or aluminum tubing. Strength and rigidity is achieved by welding the tubing together into a series of triangular shapes, called trusses.
Turbine Blades
The portion of the turbine assembly that absorbs the energy of the expanding gases and converts it into rotational energy.
Turbine discharge pressure
The total pressure at the discharge of the low-pressure turbine in a dual-turbine axial-flow engine.
Turbine engine
An aircraft engine which consists of an air compressor, a combustion section, and a turbine. Thrust is produced by increasing the velocity of the air flowing through the engine.
Turbine Outlet Temperature (TOT)
The temperature of the gases as they exit the turbine section.
Turbine Plenum
The portion of the combustor where the gases are collected to be evenly distributed to the turbine blades.
Turbine Rotors
The portion of the turbine assembly that mounts to the shaft and holds the turbine blades in place.
Turbine Section
The section of the engine that converts high pressure high temperature gas into rotational energy.
Turbocharger
An air compressor driven by exhaust gases, which increases the pressure of the air going into the engine through the carburetor or fuel injection system.
Turbofan Engine
A turbojet engine in which additional propulsive thrust is gained by extending a portion of the compressor or turbine blades outside the inner engine case. The extended blades propel bypass air along the engine axis but between the inner and outer casing. The air is not combusted but does provide additional thrust.
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.
Turbojet Engine
A jet engine incorporating a turbine-driven air compressor to take in and compress air for the combustion of fuel, the gases of combustion being used both to rotate the turbine and create a thrust producing jet.
Turboprop Aircraft
An aircraft having a jet engine in which the energy of the jet operates a turbine which drives the propeller.
Turboprop Engine
A turbine engine that drives a propeller through a reduction gearing arrangement. Most of the energy in the exhaust gases is converted into torque, rather than its acceleration being used to propel the aircraft.
Turboshaft engine
A gas turbine engine that delivers power through a shaft to operate something other than a propeller.
Turbulence
An occurrence in which a flow of fluid is unsteady.
Turn Anticipation
The capability of RNAV systems to determine the point along a course, prior to a turn WP, where a turn should be initiated to provide a smooth path to intercept the succeeding course, and to enunciate the information to the pilot.
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 WP [Turning Point]
A WP which identifies a change from one course to another.
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.
Twilight
The intervals of incomplete darkness following sunset and preceding sunrise. The time at which evening twilight ends or morning twilight begins is determined by arbitrary convention, and several kinds of twilight have been defined and used; most commonly civil, nautical, and astronomical twilight.
Twister
In the United States, a colloquial term for tornado.
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.
Type Certificate Data Sheets (TCDS)
The official specifications issued by the FAA for an aircraft, engine, or propeller.
Typhoon
A tropical cyclone in the Eastern Hemisphere with winds in excess of 65 knots (120 km/h).
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