Abbreviations marked by an asterisk (*) are either different from or not contained in ICAO Doc 8400.

† When radiotelephony is used, the abbreviations and terms are transmitted as spoken words.

‡ When radiotelephony is used, the abbreviations and terms are transmitted using the individual letters in non phonetic form.

** Signal is also available for use in communicating with stations of the maritime mobile service.

# Signal for use in the teletypewriter service only.

A - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
A Amber
AAA (or AAB, AAC...etc, in sequence) Amended meteorological message (message type designator)
A/A Air-to-air
AAD Assigned altitude deviation
AAIM Aircraft autonomous integrity monitoring
AAL Above aerodrome level
AAR Air to air refuelling
ABI Advance boundary information
ABM Abeam
ABN Aerodrome beacon
ABT About
ABV Above
AC Altocumulus
ACARS Aircraft communication addressing and reporting system †
ACAS Airborne collision avoidance system †
ACC Area control centre or area control ‡
ACCID Notification of an aircraft accident
ACFT Aircraft
ACK Acknowledge
ACL Altimeter check location
ACN Aircraft classification number
ACP Acceptance (message type designator)
ACPT Accept or accepted
ACS* Area control service
ACT Active or activated or activity
AD Aerodrome
ADA Advisory area
ADC Aerodrome chart
ADDN Addition or additional
ADF Automatic direction finding equipment ‡
ADIZ (to be pronounced "AY-DIZ") Air defence identification zone †
ADJ Adjacent
ADO Aerodrome office (specify service)
ADR Advisory route
ADS The address (when this abbreviation is used to request a repetition, the question mark (IMI) precedes the abbreviation, e.g IMI ADS) (to be used in AFS as a procedure signal) **
ADS Automatic dependent surveillance
ADS-B Automatic dependent surveillance-broadcast ‡
ADS-C Automatic dependent surveillance-contract ‡
ADSU Automatic dependent surveillance unit
ADVS Advisory service
ADZ Advise
AES Aircraft earth station
AFIL Flight plan filed in the air
AFIS Aerodrome flight information service
AFM Yes or affirm or affirmative or that is correct
AFS Aeronautical fixed service
AFT After...(time or place)
AFTN Aeronautical fixed telecommunication network ‡
A/G Air-to-ground
AGA Aerodrome, air routes and ground aids
AGL Above ground level
AGN Again
AIC Aeronautical information circular
AIDC ATS interfacility data communication
AIM Aeronautical information management
AIP Aeronautical information publication
AIRAC Aeronautical information regulation and control
AIREP Air-report †
AIRMET Information concerning en-route weather phenomena which may affect the safety of low-level aircraft operations †
AIS Aeronautical information services
ALA Alighting area
ALERFA Alert phase †
ALR Alerting (message type designator)
ALRS Alerting service
ALS Approach lighting system
ALT Altitude
ALTN Alternate or alternating (light alternates in colour)
ALTN Alternate (aerodrome)
AMA Area minimum altitude
AMC* Airspace Management Cell
AMD Amend or amended (used to indicate amended meteorological message; message type designator)
AMDT Amendment (AIP amendment)
AMS Aeronautical mobile service
AMSL Above mean sea level
AMSS Aerodrome mobile satellite service
ANC Aeronautical Chart – 1:500 000 (followed by name/title)
ANCS Aeronautical navigation chart – small scale (followed by name/title and scale)
ANS Answer
AO Aircraft operator
AOC Aerodrome obstacle chart
AP Airport
APAPI Abbreviated precision approach path indicator †
APCH Approach
APDC Aircraft parking/docking chart (followed by name/ title)
APN Apron
APP Approach control office or approach control or approach control service
APR April
APRX Approximate or approximately
APSG After passing
APU auxiliary power unit
APV Approve or approved or approval
APV Approach procedure with vertical guidance
ARC Area chart
ARNG Arrange
ARO Air traffic services reporting office
ARP Aerodrome reference point
ARP Air-report (message type designator)
ARQ Automatic error correction
ARR Arrival (message type designator)
ARR Arrive or arrival
ARS Special air-report (message type designator)
ARST Arresting (specify (part of) aircraft arresting equipment)
AS Altostratus
ASC Ascent to or ascending to
ASDA Accelerate stop distance available
ASE Altimetry system error
ASHTAM Special series NOTAM notifying, by means of a specific format, change in activity of a volcano, a volcanic eruption and/or volcanic ash cloud that is of significance to aircraft operation
ASPH Asphalt
AT At (followed by time at which weather change is forecast to occur)
ATA Actual time of arrival ‡
ATC Air traffic control (in general) ‡
ATCSMAC Air traffic control surveillance minimum altitude chart (followed by name/title)
ATD Actual time of departure ‡
ATFM Air traffic flow management
ATIS Automatic terminal information service †
ATM Air traffic management
ATN Aeronautical telecommunication network
ATP At...(time or place)
ATS Air traffic services
ATTN Attention
AT-VASIS Abbreviated T visual approach slope indicator system †
ATZ Aerodrome traffic zone
AUG August
AUTH Authorized or authorization
AUP* Airspace Use Plan
AUW All up weight
AUX Auxiliary
AVBL Available or availability
AVG Average
AVGAS Aviation gasoline †
AWOS Automatic weather observation system
AWTA Advise at what time able
AWY Airway
AZM Azimuth
B - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
B Blue
BA Braking action
BARO-VNAV Barometric vertical navigation †
BASE Cloud base †
BCFG Fog patches
BCN Beacon (aeronautical ground light)
BCST Broadcast
BDRY Boundary
BECMG Becoming
BFR Before
BKN Broken
BL Blowing (followed by DU= dust, SA= sand or SN= snow)
BLDG Building
BLO Below clouds
BLW Below ...
BOMB Bombing
BR Mist
BRF Short (used to indicate the type of approach desired or required)
BRG Bearing
BRKG Braking
BS Commercial broadcasting station
BTL Between layers
BTN Between
BUFR Binary universal form for the representation of meteorological data
C - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
C Centre (preceded by runway designation number to identify a parallel runway)
C Degrees Celsius (Centigrade)
CA Course to an altitude
CAT Category
CAT Clear air turbulence
CAVOK (to be pronounced "KAV-OH-KAY") visibility, cloud and present weather better than prescribed values or conditions †
CB (to be pronounced "CEE BEE") Cumulonimbus ‡
CC Cirrocumulus
CCA (or CCB, CCC....etc.. in sequence) corrected meteorological message (message type designator)
CD Candela
CDN Co-ordination (message type designator)
CDR Conditional Route
CF Change frequency to ...
CF Course to a fix
CFM Confirm or I confirm (to be used in AFS as a proce-dure signal) **
CGL Circling guidance light(s)
CH Channel
CH This is a channel-continuity-check of transmission to permit comparison of your record of channel-sequence numbers of messages received on the channel (to be used in AFS as a procedure signal) #
CHEM Chemical
CHG Modification (message type designator)
CI Cirrus
CIDIN† Common ICAO data interchange network
CIT Near or over large towns
CIV Civil
CK Check
CL Centre line
CLA Clear type of ice formation
CLBR Calibration
CLD Cloud
CLG Calling
CLIMB-OUT Climb-out area
CLR Clear(s) or cleared to ... or clearance
CLRD Runway(s) cleared (used in METAR/SPECI)
CLSD Close or closed or complete
cm Centimetre
CMB Climb to or climbing to
CMPL Completion or completed or complete
CNL Cancel or cancelled
CNL Flight plan cancellation message (message type designator)
CNS Communication, navigation and surveillance
COM Communications
CONC Concrete
COND Condition
CONS Continuous
CONST Construction or constructed
CONT Continue or continued
COOR Co-ordinate or coordination
COORD Coordinates
COP Change over point
COR Correct or correction or corrected (used to indicate corrected meteorological message; message type designator)
COT At the coast
COV Cover or covered or covering
CPDLC Controller-pilot data link communications ‡
CPL Current flight plan (message type designator)
CRC Cyclic redundancy check
CRP Compulsory reporting point
CRM Collision risk model
CRZ Cruise
CS Call sign
CS Cirrostratus
CTA Control area
CTAM Climb to and maintain
CTC Contact
CTL Control
CTN Caution
CTR Control zone
CU Cumulus
CUF Cumuliform
CUST Customs
CVR Cockpit voice recorder
CW Continuous wave
CWY Clearway
D - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
D Danger area (followed by identification)
D Downward (tendency in RVR during previous 10 minutes)
DA Decision altitude
D-ATIS Data link automatic terminal information service †
DCD Double channel duplex
DCKG Docking
DCP Datum crossing point
DCPC Direct controller-pilot communications
DCS Double channel simplex
DCT Direct (in relation to flight plan clearances and type of approach)
DE From (used to precede the call sign of the calling station) (to be used in AFS as a procedure signal) **
DEC December
DEG Degrees
DEP Depart or departure
DEP Departure (message type designator)
DEPO Deposition
DER Departure end of the runway
DES Descend to or descending to
DEST Destination
DETRESFA Distress phase †
DEV Deviation or deviating
DF Direction finding
DFDR Digital flight data recorder
DFTI Distances from touch down indicator
DGS Docking guidance system
DH Decision height
DIF Diffuse
DIST Distance
DIV Divert or diverting
DLA Delay (message type designator)
DLA Delay or delayed
DLIC Data link initiation capability
DLY Daily
DME Distance measuring equipment ‡
DNG Danger or dangerous
DOF Date of flight
DOM Domestic
DP Dew point temperature
DPT Depth
DR Dead reckoning
DR Low drifting (followed by DU= dust, SA= sand or SN = snow)
DRG During
DS Duststorm
DSB Double sideband
DTAM Descend to and maintain
DTG Date-time group
DTHR Displaced runway threshold
DTRT Deteriorate or deteriorating
DTW Dual tandem wheels
DU Dust
DUC Dense upper cloud
DUPE This is a duplicate message (to be used in AFS as a procedure signal) #
DUR Duration
DVOR Doppler VOR
DW Dual wheels
DZ Drizzle
E - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
E East or eastern longitude
EAT Expected approach time
eAUP* electronic Airspace Use Plan
EB Eastbound
EDA Elevation differential area
EEE Error (to be used in AFS as a procedure signal) #
EET Estimated elapsed time
EFC Expect further clearance
EFIS Electronic flight instrument system †
EGNOS European geostationary navigation overlay service †
EHF Extremely high frequency (30 000 to 300 000 MHz)
ELBA Emergency location beacon – aircraft †
ELEV Elevation
ELR Extra long range
ELT Emergency locator transmitter
EM Emission
EMBD Embedded in a layer (to indicate cumulonimbus embedded in layers of other clouds)
EMERG Emergency
EN* English
END Stop-end (related to RVR)
ENE East north east
ENG Engine
ENR En route
ENRC Enroute chart (followed by name/title)
EOBT Estimated off-block time
EQPT Equipment
ER Here… or herewith **
ET* Estonian
ESE East south east
EST Estimate or estimated or estimate (as message type designator)
ETA Estimated time of arrival or estimating arrival **‡
ETD Estimated time of departure or estimating departure ‡
ETO Estimated time over significant point
EUR RODEX European regional OPMET data exchange
eUUP* Electronic Updated Airspace Use Plan
EV Every
EVS Enhanced vision system
EXC Except
EXER Exercises or exercising or to exercise
EXP Expect or expected or expecting
EXTD Extend or extending or extended
F - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
F Fixed
FA Course from a fix to an altitude
FAB* Functional airspace block
FAC Facilities
FAF Final approach fix
FAL Facilitation of international air transport
FAP Final approach point
FAS Final approach segment
FATO Final approach and take-off area
FAX Facsimile transmission
FBL Light (used to indicate the intensity of weather phenomena, interference or static reports, e.g. FBL RA = light rain)
FBZ* Flight plan buffer zone
FC Funnel cloud (tornado or water spout)
FCST Forecast
FCT Friction coefficient
FDPS Flight data processing system
FEB February
FG Fog
FIC Flight information centre
FIR Flight information region ‡
FIS Flight information service
FISA Automated flight information service
FIZ* Flight information zone
FL Flight level
FLD Field
FLG Flashing
FLR Flares
FLT Flight
FLTCK Flight check
FLUC Fluctuating or fluctuation or fluctuated
FLW Follow(s) or following
FLY Fly or flying
FM From
FM From (followed by time weather change is forecast to begin)
FMC Flight management computer
FMP* Flow management position
FMS Flight management system ‡
FMU Flow management unit
FNA Final approach
FPAP Flight path alignment position
FPL Flight plan
FPM Feet per minute
FPR Flight plan route
FR Fuel remaining
FRA* Free route airspace
FREQ Frequency
FRI Friday
FRNG Firing
FRONT Front (relating to weather)
FROST Frost (used in aerodrome warnings)
FRQ Frequent
FSL Full stop landing
FSS Flight service
FST First
ft Feet (dimensional unit)
FTE Flight technical error
FTP Fictitious threshold point
FTT Flight technical tolerance
FU Smoke
FUA* Flexible use of airspace
FZ Freezing
FZDZ Freezing drizzle
FZFG Freezing fog
FZRA Freezing rain
G - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
G Green
G Variations from the mean wind speed (gusts) (followed by figures in METAR/SPECI and TAF)
GA Go ahead, resume sending (to be used in AFS as a procedure signal)
GA General aviation
G/A Ground-to-air
G/A/G Ground-to-air and air-to-ground
GAGAN GPS and geostationary earth orbit augmented navigation †
GAIN Airspeed or headwind gain
GAMET Area forecast for low-level operations
GARP GBAS azimuth reference point
GAT General Air Traffic
GBAS Ground-based augmentation system †
GCA Ground controlled approach system or ground controlled approach ‡
GEN General
GEO Geographic or true
GES Ground earth station
GLD Glider
GLONASS Global orbiting navigation satellite system †
GLS GBAS landing system ‡
GMC Ground movement chart (followed by name/title)
GND Ground
GNDCK Ground check
GNSS Global navigation satellite system ‡
GP Glide path
GPA Glide path angle
GPIP Glide path intercept point
GPS Global positioning system ‡
GPU Ground power unit
GPWS Ground proximity warning system ‡
GR Hail
GRAS Ground-based regional augmentation system †
GRASS Grass landing area
GRIB Processed meteorological data in the form of grid point values (aeronautical meteorological code)
GRVL Gravel
GS Ground speed
GS Small hail and/or snow pellets
GTS* Global Telecommunication System
GUND Geoid undulation
H - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
H High pressure area or the centre of high pressure
H24 Continuous day and night service
HA Holding/racetrack to an altitude
HAPI Helicopter approach path indicator
HBN Hazard beacon
HDF High frequency direction-finding station
HDG Heading
HEL Helicopter
HF High frequency (3 000 to 30 000 kHz) ‡
HF Holding/racetrack to a fix
HGT height or height above
HJ Sunrise to sunset
HLDG Holding
HLS Helicopter landing site
HM Holding/racetrack to a manual termination
HN Sunset to sunrise
HO Service available to meet operational requirements
HOL Holiday
HOSP Hospital aircraft
hPa Hectopascal
HR Hours
HS Service available during hours of scheduled operations
HUD Head-up display
HURCN Hurricane
HVDF High and very high frequency direction finding stations (at the same location)
HVY Heavy
HVY Heavy (used to indicate the intensity of weather phenomena, e.g. HVY RA = heavy rain)
HX No specific working hours
HYR Higher
HZ Haze
Hz Hertz (cycle per second)
I - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
IAC Instrument approach chart (followed by name/title)
IAF Initial approach fix
IAO In and out of clouds
IAP Instrument approach procedure
IAR Intersection of air routes
IAS Indicated air speed
IBN Identification beacon
IBOF* Integrated briefing office
IC Diamond dust (very small ice crystals in suspension, also known as diamond dust)
ICAO International Civil Aviation Organization
ICE Icing
ID Identifier or identify
IDENT Identification †
IF Intermediate approach fix
IFF Identification friend/foe
IFPS Integrated initial flight plan processing system
IFPZ Integrated initial flight plan processing zone
IFR Instrument flight rules ‡
IGA International general aviation
ILS Instrument landing system ‡
IM Inner marker
IMC Instrument meteorological conditions ‡
IMG Immigration
IMI Interrogation sign (question mark) (to be used in AFS as a procedure signal)
IMPR Improve or improving
IMT Immediate or immediately
INA Initial approach
INBD Inbound
INC In cloud
INCERFA Uncertainty phase †
INFO Information †
INOP Inoperative
INP If not possible
INPR In progress
INS Inertial navigation system
INSTL Install or installed or installation
INSTR Instrument
INT Intersection
INTL International
INTRG Interrogator
INTRP Interrupt or interruption or interrupted
INTSF intensify or intensifying
INTST Intensity
IR Ice on runway
IRS Inertial reference system
ISA International standard atmosphere
ISB Independent sideband
ISOL Isolated
J - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
JAA* Joint Aviation Authorities
JAN January
JTST Jet stream
JUL July
JUN June
K - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
kg Kilograms
kHz Kilohertz
KIAS Knots indicated airspeed
km Kilometres
km/h Kilometres per hour
KPA Kilopascal
kt Knots
kW Kilowatts
L - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
L Left (preceded by runway designation number to identify a parallel runway)
L Low pressure area or the centre of low pressure
L Locator (see LM, LO)
L Litre
LAM Logical acknowledgement (message type designator)
LAN Inland
LAT Latitude
LCA Local or locally or location or located
LDA Landing distance available
LDAH Landing distance available, helicopter
LDG Landing
LDI Landing direction indicator
LEN Length
LF Low frequency (30 to 300 kHz)
LGT Light or lighting
LGTD Lighted
LIH Light intensity high
LIL Light intensity low
LIM Light intensity medium
LINE Line (used in SIGMET)
LM Locator middle
LMT Local mean time
LNAV Lateral navigation †
LNG Long (used to indicate the type of approach desired or required)
LO Locator, outer
LOC Localizer
LONG Longitude
LORAN LORAN (long range air navigation system) †
LOSS Airspeed or headwind loss
LPV Localizer performance with vertical guidance
LR The last message received by me was... (to be used in AFS as a procedure signal)
LRG Long range
LS The last message sent by me was... or Last message was... (to be used in AFS as a procedure signal)
LTA Lower control area
LTD Limited
LTP Landing threshold point
LTT Landline teletypewriter
LV Light and variable (relating to wind)
LVE Leave or leaving
LVL Level
LVP Low visibility procedures
LVPTO* Low visibility procedures for take-off
LVTO* Low visibility take-off
LYR Layer or layered
M - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
M Mach number (followed by figures)
m Metres (preceded by figures)
M Minimum value of runway visual range (followed by figures in METAR/SPECI)
MAA Maximum authorized altitude
MAG Magnetic
MAHF Missed approach holding fix
MAINT Maintenance
MAP Aeronautical maps and charts
MAPT Missed approach point
MAR March
MAR At sea
MAS Manual A1 simplex
MASPS* Minimum aircraft system performance specification
MATF Missed approach turning fix
MAX Maximum
MBST Microburst
MCA Minimum crossing altitude
MCW Modulated continuous wave
MDA Minimum descent altitude
MDF Medium frequency direction-finding station
MDH Minimum descent height
MEA Minimum en-route altitude
MEHT Minimum eye height over threshold (for visual approach slope indicator system)
MET Meteorological or meteorology †
METAR Aviation routine weather report (in aeronautical meteorological code) †
MET REPORT Local routine meteorological report (in abbreviated plain language)
MF Medium frequency (300 kHz to 3 000 kHz)
MHA Minimum holding altitude
MHDF Medium and high frequency direction-finding station (at the same location)
MHVDF Medium, high and very high frequency direction-finding station (at the same location)
MHz Megahertz
MID Mid-point (related to RVR)
MIFG Shallow fog
MIL Military
MIN Minutes **
MIS Missing... (transmission identification) (to be used in AFS as a procedure signal)
MKR Marker radio beacon
MLS Microwave landing system ‡
MM Middle marker
MNM Minimum
MNPS Minimum navigation performance specifications
MNT Monitor or monitoring or monitored
MNTN Maintain
MOA Military operating area
MOC Minimum obstacle clearance (required)
MOCA Minimum obstacle clearance altitude
MOD Moderate (used to indicate the intensity of weather phenomena, interference or static reports e.g. MODRA = moderate rain)
MON Above mountains
MON Monday
MOPS Minimum operational performance standards †
MOV Move or moving or movement
MPS Metres per second
MRA Minimum reception altitude
MRG Medium range
MRP ATS/MET reporting point
MS Minus
MSA Minimum sector altitude
MSAS Multifunctional transport satellite (MTSAT) satellite based augmentation system †
MSAW Minimum safe altitude warning
MSG Message
MSL Mean sea level
MSR Message... (transmission identification) has been misrouted (to be used in AFS as a procedure signal) #
MSSR Monopulse secondary surveillance radar
MT Mountain
MTU Metric units
MTW Mountain waves
MTOM Maximum take-off mass
MTOW* Maximum take-off weight
MVDF Medium and very high frequency direction-finding station (at the same location)
MWO Meteorological watch office
MX Mixed type of ice formation (white and clear)
N - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
N North or northern latitude
N No distinct tendency (in RVR during previous 10 minutes)
NADP Noise abatement departure procedure
NASC National AIS system centre †
NAT North atlantic
NAV Navigation
NAVAID Navigation aid
NB North bound
NBFR Not before
NC No change
NCD No cloud detected (used in automated METAR/ SPECI)
NDB Non-directional radio beacon ‡
NDV No directional variations available (used in automated METAR/SPECI)
NE North-east
NEB North-eastbound
NEG No or negative or permission not granted or that is not correct
NEFAB* North-European functional airspace block
NGT Night
NIL None or I have nothing to send to you **
NM Nautical miles
NML Normal
NN No name, unnamed
NNE North north east
NNW North north west
NO No (negative) (to be used in AFS as a procedure signal)
NOF International NOTAM office
NONSTD Non-standard
NOSIG No significant change (used in trend-type landing forecasts)
NOTAM A notice containing information concerning the establishment, condition or change in any aeronautical facility, service, procedure or hazard, the timely knowledge of which is essential to personnel concerned with flight operations
NOV November
NOZ Normal operating zone ‡
NPA Non-precision approach
NR Number
NRH No reply heard
NS Nimbostratus
NSC Nil significant cloud
NSE Navigation system error
NSW Nil significant weather
NTL National
NTZ No transgression zone ‡
NW North-west
NWB North-westbound
NXT Next
O - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
OAC Oceanic area control centre
OAS Obstacle assessment surface
OAT Operational Air Traffic
OBS Observe or observed or observation
OBSC Obscure or obscured or obscuring
OBST Obstacle
OCA Obstacle clearance altitude
OCA Oceanic control area
OCC Occulting (light)
OCH Obstacle clearance height
OCNL Occasional or occasionally
OCS Obstacle clearance surface
OCT October
OFZ Obstacle Free Zone
OGN Originate (to be used in AFS as a procedure signal)
OHD Overhead
OIS Obstacle identification surface
OK We agree or It is correct (to be used in AFS as a procedure signal) **
OLDI On-line data interchange †
OM Out marker
OPA Opaque, white type of ice formation
OPC The control indicated is operational control
OPMET Operational meteorological (information) †
OPN Open or opening or opened
OPR Operator or operate or operative or operating or operational
OPS Operations †
O/R On request
ORD Indication of an order
OSV Ocean station vessel
OTH* Other
OTP On top
OTS Organized track system
OUBD Out-bound
OVC Overcast
P - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
P Maximum value of wind speed or runway visual range (followed by figures in METAR/SPECI and TAF)
P Prohibited area (followed by identification)
PA Precision approach
PALS Precision approach lighting system (specify category)
PANS Procedures for air navigation services
PAPI Precision approach path indicator †
PAR Precision approach radar ‡
PARL Parallel
PATC Precision approach terrain chart (followed by name/title)
PAX Passenger(s)
PBN Performance-based navigation
PCD Proceed or proceeding
PCL Pilot-controlled lighting
PCN Pavement classification number
PCT Per cent
PDC Pre-departure clearance ‡
PDG Procedure design gradient
PER Performance
PERM Permanent
PIB Pre-flight information bulletin
PJE Parachute jumping exercise
PL Ice pellets
PLA Practice low approach
PLN Flight plan
PLVL Present level
PN Prior notice required
PNR Point of no return
PO Dust/sand whirls (dust devils)
POB Persons on board
POSS Possible
PPI Plan position indicator
PPR Prior permission required
PPSN Present position
PRFG Aerodrome partially covered by fog
PRI Primary
PRKG Parking
PROB Probability †
PROC Procedure
PROP Propeller
PROV Provisional
PRP Point-in-space reference point
PS Plus
PSG Passing
PSN Position
PSP Pierced steel plank
PSR Primary surveillance radar ‡
PSYS Pressure system(s)
PTN Procedure turn
PTS Polar track structure
PWR Power
Q - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
QDL Do you intend to ask me for a series of bearings? or I intend to ask you for a series of bearings (to be used in radiotelegraphy as a Q code)
QDM Magnetic heading (zero wind) ‡
QDR Magnetic bearing
QFE Atmospheric pressure at aerodrome elevation (or at runway threshold) ‡
QFU Magnetic orientation of runway
QGE What is my distance to your station? or Your distance to my station is (distance figures and units) (to be used in radiotelegraphy as a Q Code)
QNH Altimeter sub-scale setting to obtain elevation when on the ground ‡
QTA Shall I cancel telegram number...? or Cancel telegram number... (to be used in AFS as a Q Code)
QTE True bearing
QUAD Quadrant
R - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
R Radial (followed by three figures)
R Rate of turn
R Received (acknowledgement of receipt) (to be used in AFS as a procedure signal) **
R Red
R Restricted area (followed by identification)
R Right (preceded by runway designation number to identify a parallel runway)
R Runway (followed by figures in METAR/SPECI)
RA Rain
RA Resolution advisory
RAC Rules of the air and air traffic services
RAD* Route availability document
RAFC Regional area forecast centre
RAG Ragged
RAI Runway alignment indicator
RAIM Receiver autonomous integrity monitoring †
RASC Regional AIS system centre †
RASS Remote altimeter setting source
RB Rescue boat
RCA Reach cruising altitude
RCAM Runway condition assessment matrix
RCC Rescue co-ordination centre
RCF Radiocommunication failure (message type designator)
RCH Reach or reaching
RCL Runway centre line
RCLL Runway centre line light(s)
RCLR Recleared
RCP Required communication performance ‡
RCR Runway condition report
RDH Reference datum height (for ILS)
RDL Radial
RDO Radio
RDOACT Radioactive
RE Recent (used to qualify weather phenomena, e.g. RERA = recent rain)
REC Receive or receiver
REDL Runway edge light(s)
REF Reference to ... or refer to ...
REG Registration
RENL Runway end light(s)
REP Report or reporting or reporting point
REQ Request or requested
RERTE Reroute
RESA Runway end safety area
RFFS Rescue and fire fighting services
RG Range (lights)
RHC Right-hand circuit
RIF Reclearance in flight
RIME Rime (used in aerodrome warnings) †
RITE Right (direction of turn)
RL Report leaving
RLA Relay to
RLCE Request level change en-route
RLLS Runway lead-in lighting system
RLNA Requested level not available
RMK Remark
RMZ* Radio mandatory zone
RNAV Area navigation †
RNG Radio range
RNP Required navigation performance ‡
ROBEX Regional OPMET bulletin exchange (scheme) †
ROC Rate of climb
ROD Rate of descent
RON Receiving only
RPDS Reference path data selector
RPI Radar position indicator ‡
RPL Repetitive flight plan
RPLC Replace or replaced
RPS Radar position symbol
RPT Repeat or I repeat (to be used in AFS as a procedure signal) **
RQ Request (to be used in AFS as a procedure signal) **
RQMNTS Requirements
RQP Request flight plan (message type designator)
RQS Request supplementary flight plan (message type designator)
RR Report reaching
RRA (or RRB, RRC....etc in sequence) delayed meteorological message (message type designator)
RSC Rescue sub-centre
RSCD Runway surface condition
RSP Responder beacon
RSR En-route surveillance radar
RSS Root sum square
RTD Delayed (used to indicate delayed meteorological message); message type designator)
RTE Route
RTF Radiotelephone
RTG Radiotelegraph
RTHL Runway threshold light(s)
RTN Return or returned or returning
RTODAH Rejected take-off distance available, helicopter
RTS Return to service
RTT Radioteletypewriter
RTZL Runway touchdown zone light(s)
RU* Russian
RUT Standard regional route transmitting frequencies
RV Rescue vessel
RVR Runway visual range ‡
RVSM Reduced vertical separation minimum (300 M (1000 FT)) between FL 290 and FL 410 ‡
RWY Runway
RWYCC Runway condition code
S - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
S South or southern latitude
S State of the sea (followed by figures in METAR/ SPECI)
SA Sand
SADIS Satellite Distribution System
SALS Simple approach lighting system
SAN Sanitary
SAP As soon as possible
SAR Search and rescue
SARPS Standards and recommended practices [ICAO]
SAT Saturday
SATCOM Satellite communication (used only when referring generally to both voice and data satellite communication or only data satellite communication) †
SB Southbound
SBAS Satellite-based augmentation system †
SC Stratocumulus
SCT Scattered
SD Standard deviation
SDBY Stand by
SDF Step down fix
SE South-east
SEA Sea (used in connection with sea-surface temperature and state of the sea)
SEB South-eastbound
SEC Seconds
SECN Section
SECT Sector
SELCAL Selective calling system †
SEP September
SER Service or servicing or served
SEV Severe (used e.g. to qualify icing and turbulence reports)
SFC Surface
SG Snow grains
SGL Signal
SH Showers (followed by RA=rain, SN=snow, PE=ice pellets, GR=hail, GS=small hail and or snow pellets or combinations thereof, e.g SHRASN=showers of rain and snow)
SHF Super high frequency (3 000 to 30 000 MHz)
SI International system of units
SID Standard instrument departure †
SIF Selective identification feature
SIG Significant
SIGMET Information concerning en-route weather and other phenomena in the atmosphere that may affect the safety of operations †
SIGWX* Significant weather
SIMUL Simultaneous or simultaneously
SIWL Single isolated wheel load
SKED Schedule or scheduled
SLP Speed limiting point
SLW Slow
SMAA Surveillance minimum altitude area
SMAC Surveillance minimum altitude chart
SMC Surface movement control
SMR Surface movement radar
SN Snow
SNOCLO Aerodrome being closed due to snow (used in the METAR/SPECI)
SNOWTAM A special series NOTAM notifying the presence or removal of hazardous conditions due to snow, ice, slush or standing water associated with snow, slush and ice on the movement area , by means of a specific format †
SOC Start of climb
SPECI Aviation selected special weather report (in aeronautical meteorological code) †
SPECIAL Special meteorological report (in abbreviated plain language) †
SPI Special position indicator
SPL Supplementary flight plan (message type designator)
SPOC SAR point in contact
SPOT Spot wind †
SQ Squall
SQL Squall line
SR Sunrise
SRA Surveillance radar approach
SRE Surveillance radar element of precision approach radar system
SRG Short range
SRR Search and rescue region
SRY Secondary
SS Sandstorm
SS Sunset
SSB Single sideband
SSE South south east
SSR Secondary surveillance radar ‡
SST Supersonic transport
SSW South southwest
ST Stratus
STA Straight-in approach
STAR Standard instrument arrival †
STD Standard
STF Stratiform
STN Station
STNR Stationary
STOL Short take-off and landing
STS Status
STWL Stopway light(s)
SUBJ Subject to
SUN Sunday
SUP Supplement (AIP supplement)
SUPPS Regional supplementary procedures
SVC Service (message type only)
SVCBL Serviceable
SW South-west
SWB South-westbound
SWY Stopway
T - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
T True (preceded by a bearing to indicate reference to True North)
T Temperature
TA Traffic advisory
TA Transition altitude
TAA Terminal arrival altitude
TACAN UHF tactical air navigation aid †
TAF Aerodrome forecast (in aeronautical meteorological code)†
TA/H Turn at altitude/height
TAIL Tailwind †
TAR Terminal area surveillance radar
TAS True airspeed
TAX Taxiing or taxi
TC Tropical cyclone
TCAC Tropical cyclone advisory centre
TCAS Traffic alert and collision avoidance system
TCAS RA Traffic alert and collision avoidance system resolution advisory †
TCH Threshold crossing height
TCO* Third country operator
TCU Towering cumulus
TDO Tornado
TDZ Touchdown zone
TECR Technical reason
TEL Telephone
TEMPO Temporary or temporarily †
TF Track to fix
TFC Traffic
TGL Touch-and-go landing
TGS Taxiing guidance system
THR Threshold
THRU Through
THU Thursday
TIBA Traffic information broadcast by aircraft †
TIL Until †
TIP Until past...(place)
TKOF Take off
TL Till (followed by time by which weather change is forecast to end)
TLOF Touchdown and lift-off area
TMA Terminal control area ‡
TMZ* Transponder mandatory zone
TN Minimum temperature (followed by figures in TAF)
TNA Turn altitude
TNH Turn height
TO To...(place)
TOC Top of climb
TODA Take-off distance available
TODAH Take-off distance available, helicopter
TOP Cloud top †
TORA Take-off run available
TOX Toxic
TP Turning point
TR Track
TRA Temporary reserved airspace
TRANS Transmits or transmitter
TREND Trend forecast †
TRG Training
TRL Transition level
TROP Tropopause
TS Thunderstorm (in aerodrome reports and forecasts, TS used alone means thunder heard but no precipitation at the aerodrome)
TS Thunderstorm (followed by RA= RAIN, SN= snow, PE= ice pellets, GR= hail, GS= small hail and/or snow pellets or combinations thereof, e.g TSRASN= thunderstorm with rain and snow)
TSA* Temporary segregated area
TSUNAMI Tsunami (used in aerodrome warnings) †
TT Teletypewriter
TUE Tuesday
TURB Turbulence
T-VASIS T visual approach slope indicator system †
TVOR Terminal VOR
TWR Aerodrome control tower or aerodrome control
TWY Taxiway
TWYL Taxiway-link
TX Maximum temperature (followed by figures in TAF)
TXL Taxilane
TXT Text (when the abbreviation is used to request a repetition the question mark (IMI) precedes the abbreviation, e.g. IMI TXT) (to be used in AFS as a procedure signal) **
TYP Type of aircraft
TYPH Typhoon
U - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
U Upward (tendency in RVR during previous 10 minutes)
UA Unmanned aircraft
UAB Until advised by...
UAC Upper area control centre
UAR Upper air route
UAS Unmanned aircraft system
UDF Ultra high frequency direction-finding station
UFN Until further notice
UHDT Unable higher due traffic
UHF Ultra high frequency (300 to 3 000 MHz) ‡
UIC Upper information centre
UIR Upper flight information region ‡
ULM Ultra light motorized aircraft
ULR Ultra long range
UNA Unable
UNAP Unable to approve
UNL Unlimited
UNREL Unreliable
UP Unidentified precipitation (used in automated METAR/SPECI)
U/S Unserviceable
UTA Upper control area
UTC Co-ordinated universal time ‡
UUP* Updated Airspace Use Plan
V - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
V Variations from the mean wind direction (preceded and followed by figures in METAR/SPECI, e.g. 350V070)
VA Volcanic ash
VAAC Volcanic ash advisory centre
VAC Visual approach chart (followed by name/title)
VAL In valleys
VAN Runway control van
VAR Magnetic variation
VASIS Visual approach slope indicator system
VC Vicinity of the aerodrome (followed by FG=fog, FC=funnel cloud, PO=dust-sand whirls, BLDU=blowing dust, BLSA = blowing sand or BLSN=blowing snow, e.g VCFG = vicinity fog)
VCY Vicinity
VDF Very high frequency direction-finding station
VER Vertical
VFR Visual flight rules ‡
VHF Very high frequency (30 to 300 Mhz) ‡
VIP Very important person ‡
VIS Visibility
VLF Very low frequency (3 to 30 khz)
VLR Very long range
VMC Visual meteorological conditions ‡
VNAV Vertical navigation †
VOL Volume (followed by I, II...)
VOLMET Meteorological information for aircraft in flight †
VOR VHF omnidirectional radio range ‡
VORTAC VOR and TACAN combination †
VOT VOR airborne equipment test facility
VPA Vertical path angle
VPT Visual manoeuvre with prescribed track
VRB Variable
VSA By visual reference to the ground
VSP Vertical speed
VTF Vector to final
VTOL Vertical take-off and landing
VV Vertical visibility (followed by figures in METAR/ SPECI and TAF)
W - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
W West or western longitude
W White
W Sea-surface temperature (followed by figures in METAR/SPECI)
WAAS Wide area augmentation system †
WAC World aeronautical chart ICAO 1:1 000 000 (followed by name/title)
WAFC World area forecast centre
WAM Wide area multilateration
WB Westbound
WBAR Wing bar lights
WDI Wind direction indicator
WDSPR Widespread
WED Wednesday
WEF With effect from or effective from
WGS-84 World Geodetic System – 84
WI Within
WID Width
WIE With immediate effect or effective immediately
WILCO Will comply †
WIP Work in progress
WKN Weaken or weakening
WNW West north west
WO Without
WPT Way-point
WRNG Warning
WS Wind shear
WSPD Wind speed
WSW West south west
WT Weight
WTSPT Waterspout
WWW Worldwide web
WX Weather
WXR Weather radar
X - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
X Cross
XBAR Crossbar (of approach lighting system)
XNG Crossing
XS Atmospherics
Y - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Y Yellow
YCZ Yellow caution zone (runway lighting)
YES Yes (affirmative) (to be used in AFS as a procedure signal) **
YR Your
Z - A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Z Co-ordinated universal time (in meteorological messages)