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

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 AAL        Above aerodrome level ABM      Abeam ABN       Aerodrome beacon ABT        About ABV       Above AC          Altocumulus 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 ACT        Active or activated or activity AD          Aerodrome ADA       Advisory area ADDN    Addition or additional ADF        Automatic direction finding equipment ADIZ      (to be pronounced "AY-DIZ") Air defence identification zone ADJ        Adjacent ADR       Advisory route ADS        Automatic dependent surveillance 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 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 AMD      Amend or amended (used to indicate amended meteorological message; message type designator) AMDT   Amendment (AIP amendment) AMHS* Air traffic services message handling system AMS      Aeronautical mobile service AMSL    Above mean sea level AMSS    Aerodrome mobile satellite service ANS       Answer AOC       Aerodrome obstacle chart AOM*   Aerodrome operating minima AP          Airport APCH     Approach APP        Approach control office or approach control or approach control service APR        April APRX     Approximate or approximately APSG     After passing APV       Approve or approved or approval ARFOR  Area forecast (in aeronautical meteorological code) ARNG    Arrange ARO       Air traffic services reporting office ARP        Aerodrome reference point ARP        Air-report (message type designator) ARQ       Automatic error correction ARR        Arrive or arrival ARR        Arrival (message type designator) 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 ASECNA* Agency for the Safety of Air Navigation in Africa and Madagascar 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 operations 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) 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 ATZ        Aerodrome traffic zone AUG      August AUTH    Authorized or authorization AUW     All up weight AUX       Auxiliary AVASIS Abbreviated visual approach slope indicator system AVBL     Available or availability AVG       Average AVGAS Aviation gasoline 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 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

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 (runway identification) C             Degrees celsius (Centigrade) 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) CCO       Continuous climb operation CD          Candela CDN       Co-ordination (message type designator) CDO       Continuous descent operation CDR        Conditional route (followed by a number) CF           Change frequency to ... CGL        Circling guidance light(s) CH          Channel 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 CLR         Clear(s) or cleared to ... or clearance 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 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) CRZ        Cruise 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 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 DCL*      Departure clearance via data link DCS        Double channel simplex DCT        Direct (in relation to flight plan clearances and type of approach) DEC        December DEG       Degrees DEP        Depart or departure DEP        Departure (message type designator) DES        Descend to or descending to DEST      Destination DETRESFA            Distress phase DEV        Deviation or deviating DFTI       Distances from touch down indicator DH          Decision height DIF         Diffuse DIST       Distance DIV         Divert or diverting DLA        Delay (message type designator) DLA        Delay or delayed DME      Distance measuring equipment DNG      Danger or dangerous 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 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 EB           Eastbound EET         Estimated elapsed time EFC         Expect further clearance EHF        Extremely high frequency (30 000 to 300 000 MHz) 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 ENRT     En route EOBT     Estimated off-block time EQPT     Equipment 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 EV           Every EXC        Except EXER      Exercises or exercising or to exercise EXP        Expect or expected or expecting EXTD      Extend or extending

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 FAC        Facilities FAF        Final approach fix FAL         Facilitation of international air transport FAP        Final approach point 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) FC           Funnel cloud (tornado or water spout) FCST      Forecast FCT         Friction coefficient FEB         February FEW       Few FG          Fog FIC          Flight information centre FIR          Flight information region FIS          Flight information service FISA       Automated flight information service 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) FMU      Flow management unit FNA       Final approach FPL         Filed flight plan (message type designator) FPM       Feet per minute FPR        Flight plan route FR           Fuel remaining FREQ     Frequency FRI          Friday FRNG    Firing FRONT  Front (relating to weather) FRQ        Frequent FSL         Full stop landing FSS         Flight service FST         First FT           Feet (dimensional unit) FU          Smoke 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/A        Ground-to-air G/A/G  Ground-to-air and air-to-ground GAMET Area forecast for low-level operations GCA       Ground controlled approach system or ground controlled approach GCC*     Gulf cooperation council GEN       General GEO       Geographic or true GES        Ground earth station GLD        Glider GMC      Ground movement control GND      Ground GNDCK Ground check GNSS     Global navigation satellite system GP          Glide path GR          Hail 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

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 
H24        Continuous day and night service 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) HGT       height or height above HJ           Sunrise to sunset HLDG     Holding 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 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 IAF         Initial approach fix IAO        In and out of clouds IAR         Intersection of air routes IAS         Indicated air speed IATA      International air transport association IBN         Identification beacon IC            Diamond dust (very small ice crystals in suspension, also known as diamond dust) ICE          Icing ID            Identifier or identify IDENT    Identification IF            Intermediate approach fix IFF          Identification friend/foe IFPS*     Initial flight plan processing system IFR          Instrument flight rules IGA        International general aviation ILS          Instrument landing system IM          Inner marker IMC        Instrument meteorological conditions IMG       Immigration 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 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  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 KIAS       Knots indicated airspeed KHZ        Kilohertz KM         Kilometres KMH      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 (runway identification) L              Locator (see LM, LO) LAM       Logical acknowledgement (message type designator) LAN        Inland LAT         Latitude LCN*     Load Classification Number 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 LM          Locator middle LMT       Local mean time 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) LRG        Long range LTD         Limited LTT         Landline teletypewriter LV           Light and variable (relating to wind) LVE         Leave or leaving LVL         Level 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) MAA      Maximum authorized altitude MAG     Magnetic MAINT  Maintenance MAP      Aeronautical maps and charts MAPT    Missed approach point MAR      March MAR      At sea MARS* Multiple aircraft ramp system MAS      Manual A1 simplex MAX      Maximum MAY      May MBST    Microburst MCA      Minimum crossing altitude MCC*    Maritime coordination centre 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) MF         Medium frequency (300 kHz to 3 000 kHz) 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 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) MOD     moderate (used to indicate the intensity of weather phenomena, interference or static reports e.g. MOD RA = moderate rain) MON     Above mountains MON     Monday MOTNE Meteorological Operational Telecommunications Network Europe 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 MSG      Message MSL       Mean sea level MT         Mountain MTOW  Maximum take-off weight MTU      Metric units MTW     Mountain waves 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) NAT       North atlantic NAV       Navigation NB          North bound NBFR     Not before NC          No change NDB       Non-directional radio beacon NE          North-east NEB        North-eastbound NEG       No or negative or permission not granted or that is not correct NGT       Night NIL         None or 1 have nothing to send to you NM        Nautical miles NML      Normal NNE       North north east NNW     North north west NOF       International NOTAM office 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 NR          Number NRH       No reply heard NS          Nimbostratus NSC        Nil significant cloud NSW      Nil significant weather 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 OBS        Observe or observed or observation OBSC     Observe 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 OHD       Overhead 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 OTLK      Outlook (used in SIGMET message for volcanic ash and tropical cyclones) 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 ...        Prohibited area (followed by identification) PALS      Precision approach lighting system (specify category) PANS     Procedures for air navigation services PAPI      Precision approach path indicator PAR        Precision approach radar PARL      Parallel PAX        Passenger(s) PBN       Performance-based navigation PCD        Proceed or proceeding PCN       Pavement classification number PDG       Procedure design gradient PE           Ice pellets PER        Performance PERM    Permanent PIB         Preflight information bulletin PJE         Parachute jumping exercise PLA        Practice low approach PLN        Flight plan PLVL      Present level PN          Prior notice required PNR       Point of no return PO          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 PROV    Provisional PS           Plus PSG        Passing PSN        Position PSP        Pierced steel plank 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 
QBI         Compulsory IFR flight QDM     Magnetic heading (zero wind) QDR       Magnetic bearing QFE        Atmospheric pressure at aerodrome elevation (or at runway threshold) QFU       Magnetic orientation of runway 
QNH      Altimeter sub-scale setting to obtain elevation when on the ground 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            Red R ...        Restricted area (followed by identification) R            Right (runway identification) RA          Rain RAC       Rules or the air and air traffic services RAFC     Regional area forecast centre RAG       Ragged RAG       Runway arresting gear RAI         Runway alignment indicator RB          Rescue boat RCA        Reach cruising altitude 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 RDH       Reference datum height (for ILS) RDL        Radial RDO       Radio 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 RG          Range (lights) RIF          Reclearance in flight 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    (to be pronounced "AR-NAV") Area navigation RNG       Radio range RNP       Required navigation performance ROBEX  Regional OPMET bulletin exchange(scheme) ROC       Rate of climb ROD       Rate of descent ROFOR  Route forecast (in aeronautical meteorological code) RON       Receiving only RPL         Repetitive flight plan RPLC      Replace or replaced RPS        Radar position symbol 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 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) RUT        Standard regional route transmitting frequencies RV          Rescue vessel RVR        Runway visual range RWY       Runway

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 SA           Sand 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 SB           Southbound SC           Stratocumulus SCT         Scattered SDBY      Stand by SE           South-east SEB         South-eastbound SEC         Seconds 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) SID         Standard instrument departure SIF          Selective identification feature SIGMET Information concerning en-route weather phenomena which may affect the safety of operations SIGWX  Significant weather SIMUL   Simultaneous or simultaneously SIWL      Single isolated wheel load SKC       Sky clear SKED     Schedule or scheduled SLP        Speed limiting point SLW       Slow SMC       Surface movement control SMR       Surface movement radar SN          Snow 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 SPECI     Aviation selected special weather report (in aeronautical meteorological code) SPECIAL Special meteorological report (in abbreviated plain language) 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 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              Temperature TA           Transition altitude TACAN  UHF tactical air navigation aid TAC        TACAN TAF        Aerodrome forecast TAIL       Tail, wind TAR        Terminal area surveillance radar TAS        True airspeed TAX        Taxiing or taxi TC           Tropical cyclone TCAS      Traffic alert and collision avoidance system TCH        Threshold crossing height TCU        Towering cumulus TDO       Tornado TDZ        Touchdown zone TECR      Technical reason TEL         Telephone TEMPO Temporary or temporarily TEND     Trend forecast TFC         Traffic TGL        Touch-and-go landing TGS        Taxiing guidance system THR        Threshold THRU     Through THU       Thursday 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 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 TP          Turning point TR          Track TRA       Temporary reserved airspace TRANS  Transmits or transmitter 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) TT           Teletypewriter TUE        Tuesday TURB     Turbulence TVOR     Terminal VOR TWR       Aerodrome control tower or aerodrome control TWY       Taxiway TWYL     Taxiway-link 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) UAB       Until advised by... UAC       Upper area control centre UAR       Upper air route 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 ULR       Ultra long range UNA      Unable UNAP    Unable to approve UNL       Unlimited UNREL  Unreliable U/S        Unserviceable UTA       Upper control area UTC      Co-ordinated universal time

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 
VA          Volcanic ash VAC       Visual approach chart VAL        In valleys VAN       Runway control van VAR       Magnetic variation VAR       Visual-aural radio range 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. VC FG = vicinity fog) VCY        Vicinity VDF        Very high frequency direction-finding station VDGS    Visual docking guidance system 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 VOLMET  Meteorological information for aircraft in flight VOR       VHF omnidirectional radio range VORTAC       VOR and TACAN combination VOT       VOR airborne equipment test facility VRB        Variable VSA        By visual reference to the ground VSP        Vertical speed VTOL     Vertical take-off and landing

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 WAC      World aeronautical chart-ICAO 1:1 000 000 WAFC    World area forecast centre WB         Westbound WBAR   Wing bar lights WDI       Wind direction indicator WDSPR Widespread WED      Wednesday WEF       With effect from or effective from WI          Within WID       Width WIE        With immediate effect or effective immediately WILCO  Will comply WINTEM     Forecast upper wind and temperature for aviation WIP        Work in progress WKN      Weaken or weakening WMO    World meteorological organization 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 WX        Weather

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) 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)