.
see also: AIP Canada (ICAO)

Fr: Manuel d’information aéronautique de Transports Canada
TRP Abbreviation for: tower radar plan Fr: TRP
TRSA U.S.: Abbreviation for: terminal radar service area
true airspeed The airspeed of an aircraft relative to undisturbed air. It is used primarily in flight planning and the en route portion of flight. When used in pilot/controller communications, it is referred to as “true airspeed” and not shortened to “airspeed.”
. abbreviation: TAS
Fr: vitesse air vraie
true Mach number
A ratio of the true airspeed of an aircraft to the local speed of sound at the flight altitude.
Fr: nombre de Mach vrai
TSB Abbreviation for: Transportation Safety Board of Canada Fr: BST
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. Fr: aéronef à turboréacteur
turboprop aircraft An aircraft that derives most of its propulsive power from the thrust developed by a turbojet engine having a turbine-driven propeller. Fr: aéronef à turbopropulseur
turnoff taxiway Other expression for: high speed taxiway
TWEB U.S.: Abbreviation for: transcribed weather broadcast
TWR Abbreviation for: control tower Fr: TWR
TWY Abbreviation for: taxiway Fr: TWY
U

UAV Abbreviation for: unmanned aerial vehicle Fr: UAV
UHF Abbreviation for: ultrahigh frequency Fr: UHF
ultrahigh frequency
The frequency band between 300 and 3000 MHz.
.  abbreviation: UHF
Fr: ultra-haute fréquence
ultralight aeroplane
(a)
A single-seat aeroplane that has a launch weight of 165 kg (363.8 lb) or less, and a wing area, expressed in square metres, of not less than the launch weight minus 15, divided by 10, and in no case less than 10 m2;

(b)
a two-seat instructional aeroplane that has a launch weight of 195 kg (429.9 lb) or less, and a wing area, expressed in square metres, of not less than 10 m2 and a wing loading of not more than 25 kg/m2 (5.12 lb/ft2), the wing loading being calculated using the launch weight plus the occupant weight of 80 kg (176.4 lb) per person; or 

(c)
an advanced ultralight aeroplane.

.  see also: advanced ultralight aeroplane
Fr: avion ultra-léger
“Unable”
An expression that indicates inability to comply with a specific instruction, request or clearance.
Fr: . Incapable .
uncertainty phase
(1) Canada: A phase that begins when:
(a)  
with the exception of an arrival report, no communication has been received from an aircraft within 30 min after the time a communication should have been received, or from the time an unsuccessful attempt to establish communication with such aircraft was first made, whichever is the earlier;