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OFDM
OFDM 1 Operational flight-data monitoring.
2 Orthogonal frequency-division [or domain] multiplexing.
OFDPS Oceanic flight-data processing system.
OFE Oil-free engine.
OFEMA, Ofema Office Français d’Exportation des
Matériels Aéronautiques.
OFF, Off Officer.
off-block[s] time When aircraft leaves gate [probably
travelling backwards] or starts to taxi.
offboard Released or ejected from the platform [aircraft
or ship], usually as decoy.
offboard data Supplied by sensors outside the aircraft.
off-design 1 Any operating condition other than that or
those [defined numerically] for which equipment was
intended.
2 Less common definition: at or near stall or buffet
boundary, or in severe turbulence.
offensive avionics Those carried in attacking aircraft to
assist fulfilment of mission, eg by providing navigation,
target sensing and weapon guidance.
offensive sweep Low-level flight by fighters over enemy
territory looking for targets of opportunity.
office Cockpit or flight deck (colloq.).
off-line 1 Connected to computer but not forming part
of dedicated controlled sytem.
2 Computer peripheral not directly communicating
with central processor.
3 Not on airline’s route network (eg Western Airlines
has an * office in Washington DC).
4 Computer or EDP (4) installation which stores input
data for processing when commanded.
5 No longer supplying power [usually electric] to
system.
off-mounted SSR aerial [antenna] not mounted on
primary radar but on its own turning gear, and can thus
be either synchronized to primary radar or rotated at
predetermined data rate.
offset 1 In major international purchase, eg of quantity
of combat aircraft, agreement in reverse direction in
which purchasing country is awarded one or more
contracts for products which may or may not be
connected with original hardware. This kind of * may be
(1) purely window dressing to render costly import less
unpalatable, (2) important commercial deal to benefit
original importing country, (3) designed to bolster ailing
home industry, or (4) important vehicle for transfer of
advanced technology to importer.
2 Linear distances, usually small, measured from baseline
to joggled or tapered edge, bevel, flange at angle other
than 90°, or similar part dimension.
3 Precisely defined point on ground in surface attack
(see * bombing) or in space in air interception (see * point).
4 Linear or angular difference beween major axis (eg
of aircraft or engine) and axis of drive shaft from gearbox.
5 In fir-tree root, distance between teeth measured
parallel to major axis of blade.
6 Length of normal common to landing-gear castor
axis and wheel axle [can be zero].
7 Lateral and vertical distances from desired G/S and
runway centreline of (a) an actual landing aircraft, or
(b) ILS beam (locus of peak signal strength).
8 Bearing/distance to runway threshold from point
navaid, eg Tacan.
OFV
9 See * factor).
10 See next.
offset angle 1 Angle in vertical plane between horizontal
through tug and line joining tug to glider, tow-target or
other towed body.
2 Offset (4).
offset attack See offset bombing.
offset bombing Any surface-attack procedure which
employs aiming or reference point other than target.
offset distance 1 See offset (2).
2 Distance from desired ground zero or actual ground
zero to point target or centre of area target (DoD,
NATO).
offset factor In parafoil delivery, distance divided by
drop altitude.
offset frequency simplex Two stations transmit to each
other on slightly different frequencies.
offset frontal Meeting between two DA (3) aircraft and
two hostiles (7–10 miles ahead) on reciprocal, such that no
aircraft will pass between opposing pair.
offset hinge Helicopter main-rotor hinge at substantial
radial distance from axis of rotation.
offshore procurement Procurement by direct obligation
of MAP funds of materiel outside US territory; may
include common items financed by other appropriations
(DoD). In other words, US taxpayers paid for aircraft
made in Europe, to assist industrial recovery 1951–55.
offst Offset track.
offtake Route through which power-source physical
output is extracted, notably pipe for hot bleed air or shaft
for rotary power.
off the shelf Already fully developed to military or
commercial standards and available from industry for
procurement without change to meet military requirement.
off-wing With the engine removed from the aircraft [not
necessarily an under-wing installation].
off-wing slide Emergency escape slide well ahead of or
behind wing.
OFHC Oxygen-free high-conductivity copper.
OFIC Oceanic Flight Information Centre.
OFIS, Ofis Operational Flight Information Service
(ICAO).
OF/NT Operational flight/navigation trainer (USN).
OFO Orbiting frog otolith [programme].
OFP 1 Operational flight program; LS adds loading
system (USAF).
2 Occluded frontal passage.
OFPP Office of Procurement and Policy (DoD).
OFS Operational flying school (RN).
OFSHR Offshore.
OFT 1 Operational flight trainer.
2 Operational flight test.
3 Operational flying training.
4 Orbital flight test.
5 Office of Fair Trading (UK).
6 Outer-fix time.
7 Office of Force Transformation (DoD).
8 Occupied flight time (fractional ownership).
Oftcom Office of Transport and Communications
(UK).
OFTS Operational flight and tactics simulator.
OFU Overseas Ferry Unit (RAF, WW2).
OFV Outflow valve.
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