451 / 476
441
6 – i ndex
NNW
NorthNorth-West
NOF
International NOTAMOffice
#NOZ
Normal OperatingZone
+NOTAM
Notice toAirmen
NOV
November
NPA
Non-PrecisionApproach
NR
Number
NS
Nimbostratus
NSC
Nil Significant Cloud
NSW Nil Significant weather
NTA
NoTAFAmendment
NTL
National
#NTZ
NoTransgressionZone
NVG
Night VisionGoggles (by the
MIL)
NW
North-West
NXT
Next
O
OBS
Observe, Observed,
Observation
OBSC
Obscure, Obscured, Obscuring
OBST
Obstacle
OBSTR
Obstruction
#OCA
OceanicControl Area
OCA
ObstacleClearanceAltitude
OCC
Occulting (light)
OCNL
Occasional, Occasionally
OCT
October
#OCTA
OutsideControl Area
#OCTR
OutsideControl Zone
OFZ
ObstacleFreeZone
OHD
Overhead
OK
We agreed, or It is correct
#OLDI
On LineData Interchange
OM
OuterMarker
OPA
Opaque, white type of ice
formation
OPMET
Operational Meteorological
OPN
Open, Opening,Opened
OPN
Operational Notification
Message
OPR
Operator, Operate, Operative,
Operating, Operational
OPS
Operations
O/R
OnRequest
OT
Other Times
OTLK
Outlook (used inSIGMET
messages for volcanic ash and
tropical cyclones)
OTP
On top
OUBD
Outboard
abbreviations and acronyms
CODE DEFINITION
CODE DEFINITION