| . abbreviation: NTZ
 Fr: zone de non-transgression
 “. . . now” An expression used by ATC when immediate compliance with an instruction is required to avoid an imminent situation. Fr: . ... maintenant .
 NOZ Abbreviation for: normal operating zone Fr: NOZ
 NTZ Abbreviation for: no-transgression zone Fr: NTZ
 NWS Abbreviation for: North Warning System Fr: NWS
 O
 OBST Abbreviation for: obstacle Fr: OBST obstacle All fixed (whether temporary or permanent) and mobile objects, or parts thereof, that are located on an area intended for the surface movement of aircraft or that extend above a defined surface intended to protect aircraft in flight.
 .
 abbreviation: OBST
 . also called: obstruction
 Fr: obstacle
 obstacle clearance altitude The lowest altitude above the elevation of the relevant runway threshold or above the aerodrome elevation, as applicable, used in establishing compliance with appropriate obstacle clearance criteria.
 .
 abbreviation: OCA
 . see also : obstacle clearance height
 Fr: altitude de franchissement d’obstacles
 obstacle clearance height The lowest height above the elevation of the relevant runway threshold or above the aerodrome elevation, as applicable, used in establishing compliance with appropriate obstacle clearance criteria.
 .
 abbreviation: OCH
 . see also : obstacle clearance altitude
 Fr: hauteur de franchissement d’obstacles
 obstacle clearance limit The height above the aerodrome elevation below which the minimum prescribed vertical clearance cannot be maintained either on approach or in the event of a missed approach.
 . abbreviation: OCL
 Fr: hauteur limite de franchissement d’obstacles
 obstacle light A light or one of a group of lights, usually red or white, frequently mounted on a surface structure or natural terrain to warn pilots of the presence of an obstacle. Fr: feu d’obstacle
 obstruction Other expression for: obstacle (OBST)
 OCA
 (1) Abbreviation for: obstacle clearance altitude
 Fr: OCA
 (2) Abbreviation for: oceanic control area
 Fr: OCA
 oceanic control area
 A controlled airspace extending upwards from specified limits over the high seas and over land.
 . abbreviation: OCA
 Fr: région de contr.le océanique
 OCH Abbreviation for: obstacle clearance height Fr: OCH
 OCL Abbreviation for: obstacle clearance limit Fr: OCL
 off-route vector A vector provided by ATC that takes an aircraft off a previously assigned route. Altitudes assigned by ATC during such vectors provide the required obstacle clearance. Fr: vecteur hors route
 offset parallel runways
 Runways with parallel centrelines but thresholds that are not aligned.
 Fr: pistes parallèles décalées
 OM Abbreviation for: outer marker Fr: OM
 |