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upper bramch
upper branch That half of meridian or celestial meridian
passing through observer or observer’s zenith.
Upper Flight Information Region Same geographic areas
as FIR but imposes special rules above 24,500 ft (7468 m)
[in US, 25,000 ft, 7,620 m].
upper limb That half of limb of celestial body having
greater altitude.
upper sideband USB = carrier frequency + modulation
frequency; it carries the information.
upper stage Second or subsequent stage in multistage
rocket, in most vehicles not fired in atmosphere.
upper-surface aileron Split surface forming part of upper
surface of wing only, used for roll or, in some cases, as
spoiler (rare).
upper-surface blowing Discharge of main propulsive jets
(flattened laterally to cover more span) across top of wing;
in high-lift mode deflected down by Coanda-effect attachment
to upper surface of large trailing-edge flaps to give
augmented lift. Can achieve C L up to about 12 but reduces
cruise efficiency.
upper-tier technology That required for exoatmospheric
ballistic-missile defence.
upper wing Top wing of biplane; hence ** pylon, pylon
attached above top plane of biplane.
UPPL Undergraduate private pilot’s licence.
UPR 1 Upper airspace.
2 User-preferred routing [air route].
uprated Cleared to deliver more power, usually but not
necessarily after incorporation of improvements; eg * gas
turbine may operate at higher TGT or incorporate more
efficient blades with reduced tip clearance; hence
uprating, process of authorizing greater output from
existing or improved machine.
uprig To adjust neutral position of spoiler or airbrakes
(normally recessed in upper surface of wing) to provide
up/down direct lift control.
UPRM Universal platform resource management.
UPS 1 Uninterruptable power supply, or supplies.
2 UV photoelectron spectroscopy.
upset 1 Sudden externally imposed or undesired disturbance
to flightpath, eg by violent gust. Classed as
moderate if not worse than zero-g, severe if vertical
acceleration is strongly negative. Usual definition of
severe includes speed varying anywhere from Vs to V DF ,
bank 60° and pitch 30°.
2 Metalworking process akin to forging in which rod
or other slender workpiece is heated and placed under
axial compression to reduce length and increase diameter,
usually at particular place and to attain particular longitudinal
profile.
upset rate Frequency of problems suffered by
computer[s] due to radiation.
UPSLP Upslope.
UPSMS UPS(1) management system.
upstage In a direction towards nose of multistage
ballistic vehicle; * and downstage can refer to positions of
items within same stage or to items in different stages.
upstairs 1 Aloft, ie flying (colloq.).
2 High altitude, especially as distinct from low.
upstream injection Fuel is sprayed in opposite direction
to engine airflow.
UPT Undergraduate pilot training (S adds system.)
uptime Time when equipment is available for use.
UPU Universal Postal Union (Int.).
USAAAVS
upward Charlie Upward roll (UK colloq.).
upward ident Upward identification light; white light
visible from hemisphere above aircraft and usually
provided with manual keying from cockpit, eg to send
aircraft callsign or other message.
upward roll Roll while in steep climb, usually zoom after
fast low pass.
upwash 1 Upward movement of air around outside of
trailing vortex behind wing giving positive lift, usually
curving over to become downwash on inner side of vortex.
2 Upward movement of air ahead of leading edge of
subsonic wing giving positive lift.
3 See fountain.
upwind Towards the direction from which the wind is
coming: G/S = TAS - W/V.
UQ Ultra-quick (fuze).
UR 1 Unsatisfactory report.
2 Unscheduled removal.
U R Helicopter rotor-blade radial velocity along blade at
plane of disk.
U r Gust reference velocity.
URA 1 Unrestricted article.
2 Ultra-reliable aircraft.
uranium U, silvery radioactive metal, density 19.0, MPt
1,132°C. See nuclear weapon, depleted *.
URAV Uninhabited, or unmanned, reconnaissance air
vehicle.
URCS Unmanned radar and communications station.
URD User requirement[s] document.
URE Unintentional radiation exploitation.
UREA Universities Research Assessment Exercise
(UK).
urea CO(NH 2 ) 2 , traditional runway deicer, also used in
some plastics.
URET User-request evaluation tool; CCLD adds corecapability
limited deployment (FAA/FFP-1).
Ureti University research, engineering and technology
institutes (NASA-DoD).
URG Underway Replenishment Group.
urinal Same word can mean an overboard tube or a sealable
bladder.
URIPS, Urips Undersea radioisotope power supply.
Urits USAF rangeless instrumentation [originally
interim] training system, not compatible with Actions and
Raids, which are not compatible with each other.
URR 1 Ultra-reliable radar.
2 Ultimate recoverable reserve [petroleum].
URS User-requirements specification.
Ursi, URSI Union Radio Scientifique International
(Int., pronounced as word).
URTA Upset recovery training aid.
URV Unmanned research vehicle.
URVC Unshielded rudder volume coefficient.
US 1 Under instruction.
2 Ultrasonic (sometimes U/S).
U/S, U/s Unserviceable.
u/s Unsubstantiated intelligence.
U s Gust velocity at distance s into the gust.
USA 1 United States Army.
2 Useful screen area (HDD).
3 United Space Alliance, a linking of US industrial
firms.
usa Usable screen area [meaning same as USA (2)].
USAAAVS USA Agency for Aviation Safety.
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