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.
(See VORTAC.)
(Refer to AIM.)
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-
(See LANDING 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.
(See RADAR.)
(See TARGET SYMBOL.)
(See ICAO term TARGET.)
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.
(See AIR TAXI.)
(See HOVER TAXI.)
(Refer to AIM.)
(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.
(Refer to AIM.)
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.)
(See TOWER.)
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 AIM.)
(Refer to AIRPORT/FACILITY DIRECTORY.)
(See TERMINAL RADAR PROGRAM.)
(Refer to AIM.)
(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.
(See NAVIGATIONAL AID.)
(See VOR.)
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.
(See SEGMENTED CIRCLE.)
(Refer to AIM.)
TF-
(See TERRAIN FOLLOWING.)
THAT IS CORRECT- The understanding you have is
right.
360 OVERHEAD-
(See OVERHEAD APPROACH.)
THRESHOLD- The beginning of that portion of the
runway usable for landing.
(See AIRPORT LIGHTING.)
(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.
(See GLIDESLOPE.)
(See THRESHOLD.)
THRESHOLD LIGHTS-
(See AIRPORT LIGHTING.)
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-
(See 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.
(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-
(See VISIBILITY.)
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.
(See TOUCHDOWN ZONE.)
TOUCHDOWN ZONE LIGHTING-
(See AIRPORT 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 MOVEMENT AREA.)
(See TOWER EN ROUTE CONTROL SERVICE.)
(Refer to AIM.)
(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.)
(See TRANSPONDER.)
TRACK- The actual flight path of an aircraft over
the surface of the earth.
(See COURSE.)
(See ROUTE.)
(See FLIGHT PATH.)
(See ICAO term TRACK.)
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:
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
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.
(Refer to AIM.)
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 NEGATIVE CONTACT.)
(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 TAXI PATTERNS.)
(Refer to AIM.)
(Refer to FAR Part 91.)
(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.
(Refer to AIM.)
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).
(See VISIBILITY.)
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 INTERROGATOR.)
(Refer to AIM.)
(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-
(See 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.)
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