Pilot/Controller Glossary

UNMANNED AIRCRAFT (UA)- A device used or intended to be used for flight that has no onboard pilot. This
device can be any type of airplane, helicopter, airship, or powered-lift aircraft. Unmanned free balloons, moored
balloons, tethered aircraft, gliders, and unmanned rockets are not considered to be a UA.
UNMANNED AIRCRAFT SYSTEM (UAS)- An unmanned aircraft and its associated elements related to safe
operations, which may include control stations (ground, ship, or air based), control links, support equipment,
payloads, flight termination systems, and launch/recovery equipment. It consists of three elements: unmanned
aircraft, control station, and data link.
UNPUBLISHED ROUTE- A route for which no minimum altitude is published or charted for pilot use.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.)

UNRELIABLE (GPS/WAAS)- An advisory to pilots indicating the expected level of service of the GPS and/or
WAAS may not be available. Pilots must then determine the adequacy of the signal for desired use.
UNSERVICEABLE (U/S)
(See OUT OF SERVICE/UNSERVICEABLE.)

UPWIND LEG-
(See TRAFFIC PATTERN.)

URBAN AIR MOBILITY (UAM)- A subset of Advanced Air Mobility (AAM), referring to an air transportation
system utilizing highly automated aircraft to transport passengers or cargo in urban/suburban areas.
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.)

UTM-
(See UAS TRAFFIC MANAGEMENT.)