TACAN -- TWO-WAY RADIO COMMUNICATIONS FAILURE
TACAN- (See TACTICAL AIR NAVIGATION.)
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.
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-
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.
TARGET- The 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.
TARGET RESOLUTION- A process to ensure that correlated radar
targets do not touch. Target resolution shall be applied as follows:
a. Between the edges of two primary targets or the edges of the
ASR-9 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.
MANDATORY
TRAFFIC ADVISORIES AND SAFETY ALERTS SHALL BE ISSUED WHEN THIS PROCEDURE IS
USED.
Note: This procedure shall not be provided utilizing mosaic radar systems.
TARGET SYMBOL- A computer-generated indication shown on a radar display
resulting from a primary radar return or a radar beacon reply.
TAXI- The movement of an airplane under its own power on the surface of an
airport (FAR Part 135.100 [Note]). Also, it describes the surface movement of
helicopters equipped with wheels.
(Refer to FAR Part 135.100.)
TAXI INTO POSITION AND HOLD-
Used by ATC to inform a pilot to taxi onto the departure runway in
takeoff position and hold. It is not authorization for takeoff. It is used when
takeoff clearance cannot immediately be issued because of traffic or other
reasons.
(See CLEARED FOR TAKEOFF.)
TAXI PATTERNS- Patterns established to
illustrate the desired flow of ground traffic for the different runways or
airport areas available for use.
TCAS-
(See TRAFFIC ALERT AND COLLISION AVOIDANCE SYSTEM.)
TCH-
(See THRESHOLD CROSSING HEIGHT.)
TCLT-
(See TENTATIVE CALCULATED LANDING TIME.)
TDZE-
(See TOUCHDOWN ZONE ELEVATION.)
TELEPHONE INFORMATION BRIEFING
SERVICE- A continuous telephone recording of meteorological and/or aeronautical
information.
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 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.
(See APPROACH CONTROL FACILITY.)
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. TRSA's 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.
a. Basic Radar Service- These services are provided for VFR
aircraft by all commissioned terminal radar facilities. Basic radar service
includes safety alerts, traffic advisories, limited radar vectoring when
requested by the pilot, and sequencing at locations where procedures have been
established for this purpose and/or when covered by a letter of agreement. The
purpose of this service is to adjust the flow of arriving IFR and VFR aircraft
into the traffic pattern in a safe and orderly manner and to provide traffic
advisories to departing VFR aircraft.
b. 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.
c. Class C Service- This service provides, in addition to basic
radar service, approved separation between IFR and VFR aircraft, and
sequencing of VFR aircraft, and sequencing of VFR arrivals to the primary
airport.
d. Class B Service- This service provides, in addition to basic
radar service, approved separation of aircraft based on IFR, VFR, and/or
weight, and sequencing of VFR arrivals to the primary airport(s).
(See CONTROLLED AIRSPACE.)
(See TERMINAL RADAR SERVICE AREA.)
(Refer to AIRPORT/FACILITY DIRECTORY.)
(See TERMINAL RADAR PROGRAM.)
(Refer to 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 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.
TETRAHEDRON- A device normally located on uncontrolled airports and used as a
landing direction indicator. The small end of a tetrahedron points in the
direction of landing. At controlled airports, the tetrahedron, if installed,
should be disregarded because tower instructions supersede the indicator.
TF-
THAT IS CORRECT- The
understanding you have is right.
360 OVERHEAD-
THRESHOLD- The beginning of that portion
of the runway usable for landing.
(See DISPLACED THRESHOLD.)
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 LIGHTS-
TIBS-
(See TELEPHONE INFORMATION BRIEFING SERVICE.)
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.
TMPA-
(See TRAFFIC MANAGEMENT PROGRAM ALERT.)
TMU-
(See TRAFFIC MANAGEMENT UNIT.)
TODA [ICAO]-
(See ICAO Term TAKE-OFF DISTANCE AVAILABLE.)
TORA [ICAO]-
(See ICAO Term TAKE-OFF RUN AVAILABLE.)
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.
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 takeoff to arrive over the
destination aerodrome.
(See ESTIMATED ELAPSED TIME.)
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-
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.
(See ICAO term TOUCHDOWN.)
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.
TOUCHDOWN RVR-
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.
(See ICAO term TOUCHDOWN ZONE.)
TOUCHDOWN ZONE [ICAO]- The portion
of a runway, beyond the threshold, where it is intended landing aircraft first
contact the runway.
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 LIGHTING-
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).
(See AIRPORT TRAFFIC CONTROL SERVICE.)
(See APPROACH CONTROL FACILITY.)
(See APPROACH CONTROL SERVICE.)
(See TOWER EN ROUTE CONTROL SERVICE.)
(See ICAO term AERODROME CONTROL TOWER.)
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-
(See TOWER EN ROUTE CONTROL SERVICE.)
TPX-42- A numeric beacon
decoder equipment/system. It is designed to be added to terminal radar systems
for beacon decoding. It provides rapid target identification, reinforcement of
the primary radar target, and altitude information from Mode C.
(See AUTOMATED RADAR TERMINAL SYSTEMS.)
TRACK- The actual flight path of an aircraft
over the surface of the earth.
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).
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:
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
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 should not assume that all
traffic will be issued.
TRAFFIC ALERT (aircraft call sign), TURN
(left/right) IMMEDIATELY, (climb/descend) AND MAINTAIN (altitude). (See
SAFETY ALERT.)
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 INFORMATION-
(See TRAFFIC ADVISORIES.)
TRAFFIC IN SIGHT- Used by
pilots to inform a controller that previously issued traffic is in sight.
(See TRAFFIC ADVISORIES.)
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 ARTCC's and designated terminals
responsible for direct involvement 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. The components of a typical traffic
pattern are upwind leg, crosswind leg, downwind leg, base leg, and final
approach.
a. Upwind Leg- A flight path parallel to the landing runway in the
direction of landing.
b. Crosswind Leg- A flight path at right angles to the landing
runway off its upwind end.
c. Downwind Leg- A flight path parallel to the landing runway in
the direction opposite to landing. The downwind leg normally extends between
the crosswind leg and the base leg.
d. Base Leg- A flight path at right angles to the landing runway
off its approach end. The base leg normally extends from the downwind leg to
the intersection of the extended runway centerline.
e. Final Approach. A flight path in the direction of landing along
the extended runway centerline. The final approach normally extends from the
base leg to the runway. An aircraft making a straight-in approach VFR is also
considered to be on final approach.
(See STRAIGHT-IN APPROACH VFR.)
(See ICAO term AERODROME TRAFFIC CIRCUIT.)
TRANSCRIBED WEATHER
BROADCAST- A continuous recording of meteorological and aeronautical information
that is broadcast on L/MF and VOR facilities for pilots.
TRANSFER OF CONTROL- That action whereby the
responsibility for the separation of an aircraft is transferred from one
controller to another.
(See ICAO term TRANSFER OF CONTROL.)
TRANSFER OF CONTROL [ICAO]-
Transfer of responsibility for providing air traffic control service.
TRANSFERRING CONTROLLER- A controller/facility transferring control of an
aircraft to another controller/facility.
(See ICAO term TRANSFERRING UNIT/CONTROLLER.)
TRANSFERRING
FACILITY-
(See 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. 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.
b. 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.
(Refer to DP/STAR Charts.)
TRANSITIONAL AIRSPACE- That portion of
controlled airspace wherein aircraft change from one phase of flight or flight
condition to another.
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.
TRANSMISSOMETER- An apparatus used to determine visibility by measuring the
transmission of light through the atmosphere. It is the measurement source for
determining runway visual range (RVR) and runway visibility value (RVV).
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.
(See ICAO term TRANSPONDER.)
TRANSPONDER [ICAO]- A
receiver/transmitter which will generate a reply signal upon proper
interrogation; the interrogation and reply being on different frequencies.
TRANSPONDER CODES-
TRSA-
(See TERMINAL RADAR SERVICE AREA.)
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).
TVOR-
(See TERMINAL-VERY HIGH FREQUENCY OMNIDIRECTIONAL RANGE
STATION.)
TWEB-
(See TRANSCRIBED WEATHER BROADCAST.)
TWO-WAY RADIO COMMUNICATIONS
FAILURE-
(See LOST COMMUNICATIONS.)