| O&M |
Operations & maintenance |
| OAT |
Outside air temperature |
| OBIGGS |
On-board inert gas generating system |
| oblique wing |
Wing pivoted at mid-point so that one-half is
swept forward, the other half swept |
| |
backward; aka 'slew wing' |
| OBOGS |
On-board oxygen generating system |
| OBS |
Omni-bearing selector; also:
on-board simulation |
| OC |
Officer commanding |
| OCA |
Obstacle clearance altitude |
| OCH |
Obstacle clearance height |
| OCU |
Operational conversion unit;
also: operational capabilities upgrade |
| OEI |
One engine inoperative |
| OEU |
Operational evaluation unit |
| offset |
Agreement with a customer nation to contract
local workshare; helps to offset |
| |
purchase costs of aircraft/system aquisition and
creates local employment |
| OG |
Operations Group (USAF) |
| OGE |
Out of ground effect; helicopter hovering
performance far above land or water surface |
| OGMA |
Oficinas Gerais de Material Aeronautico
(Portugal) |
| OKB |
Opytno-Kunstruktorskoye Byuro; Russian
designation for aircraft or missile design |
| |
bureau |
| Omega |
Long-range radio navigation aid |
| OMI |
Omni-bearing magnetic indicator |
| Opeval |
Operational evaluation |
| OR |
Operational requirement (RAF) |
| OSS |
Operational Support Squadron (USAF) |
| OTH |
Over the horizon |
| OTHT |
Over the horizon targeting |
| OTU |
Operational training unit |
| outer marker |
ILS marker situated on centerline of approach,
about 4.5 nm (8.3 km) from runway |
| |
threshold |
| OWE |
Operating weight empty |