Glossary — O

OAO Otkrytolye Aktsionernoye Obshchestvo (JSC; Russian company constitution).

OAT Outside air temperature.

OBIGGS Onboard inert gas generating system.

OBOGS Onboard oxygen generating system.

OCU (1) Operational Conversion Unit; (2) Operational Capabilities Upgrade.

OEI One engine inoperative.

OEU Operational Evaluation Unit.

offset Workshare granted to a customer nation to offset the cost of an imported system.

OGE Out of ground effect; helicopter hovering, far above nearest surface.

OKB Opytnyi Konstruktorskoye Byuro (Russian experimental design bureau).

Omega Long-range hyperbolic radio navaid.

000 Obshchestvo Ogranichennoye Otvetstvennostyu (Russian company constitution).

opeval Operational evaluation.

OSD Out-of-Service Date.

OSF Optronique Secteur Frontale.

OTH Over-the-horizon.

OTHT Over-the-horizon targeting.

OTPI On-top position indicator (indicates overhead of submarine in ASW).

OWE Operating weight empty. MTOW minus payload, usable fuel and oil and other consumables (thus, includes crew).