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U
UDF-
(See
DIRECTION FINDER.)
UHF-
(See ULTRAHIGH FREQUENCY.)
ULTRAHIGH FREQUENCY-
The frequency band between 300 and 3,000 MHz. The bank of radio
frequencies used for military air/ground voice communications. In some
instances this may go as low as 225 MHz and still be referred to as
UHF.
ULTRALIGHT VEHICLE-
An aeronautical vehicle operated for sport or recreational purposes
which does not require FAA registration, an airworthiness certificate,
nor pilot certification. They are primarily single occupant vehicles,
although some two-place vehicles are authorized for training purposes.
Operation of an ultralight vehicle in certain airspace requires
authorization from ATC.
(Refer to
14 CFR Part 103.)
UNABLE-
Indicates inability to comply with a specific instruction, request, or
clearance.
UNDER THE HOOD-
Indicates that the pilot is using a hood to restrict visibility
outside the cockpit while simulating instrument flight. An
appropriately rated pilot is required in the other control seat while
this operation is being conducted.
(Refer to
14 CFR Part 91.)
UNFROZEN- The Scheduled Time of Arrival (STA) tags,
which are still being rescheduled by traffic management advisor (TMA)
calculations. The aircraft will remain unfrozen until the time the
corresponding estimated time of arrival (ETA) tag passes the preset
freeze horizon for that aircraft's stream class. At this point the
automatic rescheduling will stop, and the STA becomes "frozen."
UNICOM- A nongovernment
communication facility which may provide airport information at
certain airports. Locations and frequencies of UNICOMs are shown on
aeronautical charts and publications.
(See AIRPORT/FACILITY DIRECTORY.)
(Refer to AIM.)
UNPUBLISHED ROUTE-
A route for which no minimum altitude is published or charted for
pilot use. It may include a direct route between NAVAIDs, a radial, a
radar vector, or a final approach course beyond the segments of an
instrument approach procedure.
(See
PUBLISHED ROUTE.)
(See ROUTE.)
UPWIND LEG-
(See
TRAFFIC PATTERN.)
URET-
(See USER REQUEST EVALUATION TOOL CORE CAPABILITY LIMITED DEPLOYMENT.)
URET CCLD-
(See USER REQUEST EVALUATION TOOL CORE CAPABILITY LIMITED DEPLOYMENT.)
URGENCY- A condition of being
concerned about safety and of requiring timely but not immediate
assistance; a potential distress condition.
(See ICAO term URGENCY.)
URGENCY [ICAO]- A
condition concerning the safety of an aircraft or other vehicle, or of
person on board or in sight, but which does not require immediate
assistance.
USAFIB-
(See ARMY AVIATION FLIGHT INFORMATION BULLETIN.)
USER REQUEST EVALUATION TOOL CORE CAPABILITY LIMITED DEPLOYMENT (URET
CCLD)- User Request Evaluation Tool Core Capability Limited
Deployment is an automated tool provided at each Radar Associate
position in selected En Route facilities. This tool utilizes flight
and radar data to determine present and future trajectories for all
active and proposal aircraft and provides enhanced, automated flight
data management.
UVDF-
(See
DIRECTION FINDER.)
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