Definition |
Contraction |
Usage |
|
Obliterate |
OBL |
GEN |
|
obscure |
OBSC |
NWS |
|
obscured sky condition |
X |
NWS |
|
observation |
OBS |
NWS |
|
obstacle |
OBST |
ICAO |
|
obstacle assessment surface |
OAS |
ICAO |
|
obstacle clearance altitude |
OCA |
ICAO |
|
obstacle clearance height |
OCH |
ICAO |
|
obstacle clearance limit |
OCL |
ICAO |
|
obstacle clearance surface |
OCS |
ICAO |
|
Obstacle free zone |
OFZ |
ICAO |
|
obstruct |
OBST |
GEN |
|
obstruction |
OBSTN |
GEN |
|
obstruction chart |
OC |
GEN |
|
occasional |
OCNL |
GEN |
|
occlude |
OCLD |
NWS |
|
occluded frontal passage |
OFP |
NWS |
|
occlusion |
OCLN |
NWS |
|
occluded front |
OCFNT |
NWS |
|
occur |
OCR |
GEN |
|
ocean station vessel |
OSV |
NWS |
|
oceanic air route tracking system |
OARTS |
GEN |
|
oceanic area control |
OAC |
GEN |
|
oceanic ATC |
OCAC |
GEN |
|
oceanic control area |
OCA |
ICAO |
|
Oceanic Display and Planning System |
ODAPS |
ATC |
|
oceanic navigational error report |
ONER |
ATC |
|
off watch |
OFW |
GEN |
|
office |
OFC |
GEN |
|
official |
OFFL |
GEN |
|
Official Airline Guide |
OAG |
GEN |
|
offshore |
OFSHR |
NWS |
|
omni intersection |
OINT |
GEN |
|
omnidirectional approach lighting system |
ODALS |
GEN |
|
on and off instruments |
OAOI |
ATC |
|
on board |
OB |
GEN |
|
on course |
OC |
ATC |
|
on file |
O/F |
GEN |
|
on ground |
OG |
ATC |
|
on instruments |
OI |
ATC |
|
On line data interchange |
OLDI |
ICAO |
|
on request |
O/R |
GEN |
|
on shore |
ONSHR |
NWS |
|
on time |
OT |
ATC |
|
on top |
OTP |
ATC |
|
on top and smooth |
OTAS |
NWS |
|
on watch |
ONW |
GEN |
|
one way |
OW |
GEN |
|
Ontario |
ONT |
NWS |
|
on-the-job training |
OJT |
GEN |
|
opaque, white type of ice formation |
OPA |
ICAO |
|
open |
OPN |
ICAO |
|
operate |
OPER |
GEN |
|
operate, operator, operational |
OPR |
ICAO |
|
operating normally |
OK |
GEN |
|
operation |
OPN |
GEN |
|
operation and regulation |
OANDR |
GEN |
|
operational control |
OPC |
ICAO |
|
operational information system |
OIS |
ATC |
|
operational meteorological (information) |
OPMET |
ICAO |
|
operations |
OPS |
ICAO |
|
operations network |
OPSNET |
ATC |
|
operations normal |
OPNML |
GEN |
|
opposite direction traffic |
OPDT |
GEN |
|
optical landing system |
OLS |
ATC |
|
optimum working frequency |
OWF |
GEN |
|
order, indication of |
ORD |
ICAO |
|
organized track system |
OTS |
GEN |
|
original |
ORIG |
GEN |
|
original flight plan |
OFP |
GEN |
|
Originate |
OGN |
ICAO |
|
orographic |
ORGPHC |
NWS |
|
other |
OTR |
GEN |
|
otherwise |
OTRW |
GEN |
|
our message |
OMSG |
GEN |
|
out for maintenance |
OFM |
GEN |
|
out of control area |
OCTLA |
ATC |
|
out of controlled airspace |
OCAS |
ATC |
|
out of service |
OTS |
GEN |
|
out of tolerance |
OOT |
GEN |
|
outbound |
OBND |
ATC |
|
outbound |
OUBD |
ICAO |
|
outer fix time |
OFXT |
ATC |
|
outer locator |
LO |
ICAO |
|
outer marker |
OM |
GEN |
|
outlook |
OTLK |
NWS |
|
outside air temperature |
OAT |
GEN |
|
over |
OVR |
GEN |
|
over mountains |
OMTNS |
NWS |
|
over range station |
ORS |
ATC |
|
overcast |
OVC |
NWS |
|
overdue |
OVD |
GEN |
|
overflight traffic |
OTFC |
GEN |
|
overhead |
OHD |
ICAO |
|
overhead |
OVHD |
GEN |
|
overhead approach |
OA |
ATC |
|
overlay |
OVLA |
GEN |
|
overnight |
OVNGT |
GEN |
|
overrun |
OVRN |
GEN |
|
overrun lights |
ORL |
GEN |
|
overseas |
OVSEA |
GEN |
|
overseas flight assistance service |
OFAS |
GEN |
|
overtake |
OVTK |
GEN |
|
overtime |
O/T |
GEN |
|
oxygen |
OXY |
GEN |