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 GLOSSARY OF TERMS | |
| 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 |
| AFI | Africa/Indian Ocean |
| AFIL | Flight plan filed in the air |
| AFIS | Aerodrome flight information service |
| AFM | Yes or affirm or affirmative or that is correct |
| AFPL | Abbreviated flight plan |
| AFS | Aeronautical fixed service |
| AFT | After... (time or place) |
| A/G | Air-to-ground |
| AGA | Aerodromes, air routes and ground aids |
| AGL | Above ground level |
| 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 |
| AMC | Airspace management cell |
| AMD | Amend or amended (used to indicate amended meteorological message; message type designator) |
| AMDT | Amendment (AIP amendment) |
| AMHS | Aeronautical message handling system |
| AMS | Aeronautical mobile service |
| AMSL | Above mean sea level |
| AMSS | Aeronautical mobile satellite service |
| ANS | Answer |
| AOC | Aerodrome obstacle chart |
| AOR | Area of responsibility |
| 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 |
| ARCC | Aeronautical rescue coordination centre |
| 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) |
| ARST | Arresting (specify (part of) aircraft arresting equipment) |
| AS | Altostratus |
| ASC | Ascend or ascending to |
| ASDA | Accelerate-stop distance available |
| 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 servce |
| 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 |
| AWOS | Automated weather observing 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 GLOSSARY OF TERMS | |
| 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 |
| B-RNAV | Basic area navigation |
| 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 GLOSSARY OF TERMS | |
| C | Centre (runway identification) |
| C | Degrees Celsius (Centigrade) |
| C | Chart |
| 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 type designator) |
| CD | Candela |
| CDN | Co-ordination (message type designator) |
| *CDR | Conditional route |
| CF | Change frequency to... |
| CF | Course to a fix |
| 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 closing |
| CM | Centimetre |
| CMB | Climb to or climbing to |
| CMPL | Completion or completed or complete |
| CNL | Cancel or cancelled |
| CNL | Flight plan cancellation (message type designator) |
| CNS | Communications, navigation and surveillance |
| COM | Communications |
| CONC | Concrete |
| COND | Condition |
| CONS | Continuous |
| CONST | Construction or constructed |
| CONT | Continue(s) or continued |
| COOR | Co-ordination |
| 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 |
| CTOT | Calculated Take-Off Time |
| 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 GLOSSARY OF TERMS | |
| D | Danger area (followed by identification) |
| D | Downward (tendency in RVR during previous 10 minutes) |
| DA | Decision altitude |
| DCD | Double channel duplex |
| DCKG | Docking |
| DCS | Double channel simplex |
| DCT | Direct (in relation to flight plan clearances and type of approach) |
| DEC | December |
| DEG | Degrees |
| DENEB | Fog dispersal operations |
| DEP | Depart or departure |
| DEP | Departure (message type designator) |
| DES | Descend to… or descending to… |
| DEST | Destination |
| DETRESFA | Distress phase |
| DEV | Deviation or deviating |
| *DF | Direct to a fix |
| DFTI | Distance from touchdown 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 |
| DNM | Directorate Network Management |
| 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 |
| 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 GLOSSARY OF TERMS | |
| 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) |
| ELBA | Emergency location beacon-aircraft |
| ELEV | Elevation |
| ELR | Extra long range |
| EM | Emission |
| EMBD | Embedded in layer (to indicate cumulonimbus embedded in layers of other clouds) |
| EMERG | Emergency |
| END | Stop-end (related to RVR) |
| ENE | East north east |
| ENG | Engine |
| ENRT | En route |
| EOBT | Estimated off-block time |
| EQPT | Equipment |
| ER | Here... or herewith |
| ESE | East south east |
| EST | Estimate or estimated or estimate (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 | European (ICAO region) |
| 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 GLOSSARY OF TERMS | |
| F | Fixed |
| *FAB | Functional Airspace Block |
| 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 |
| 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) |
| FMS | Flight management system |
| FNA | Final approach |
| FPL | Filed flight plan (message type designator) |
| 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) |
| FRQ | Frequent |
| FSL | Full stop landing |
| FSS | Flight service station |
| 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 GLOSSARY OF TERMS | |
| G | Green |
| G/A | Ground-to-air |
| G/A/G | Ground-to-air and air-to-ground |
| GAMET | Area forecast for low-level flights |
| GAT | General air traffic |
| GEN | General |
| GEO | Geographic or true |
| GES | Ground earth station |
| GLD | Glider |
| GND | Ground |
| GNDCK | Ground check |
| GNSS | Global navigation satellite system |
| GP | Glide path |
| GPS | Global position system |
| GR | Hail |
| GRASS | Grass landing area |
| GRIB | Processed meteorological data in the form of grid point values (in aeronautical meteorological code) |
| GRVL | Gravel |
| GS | Ground speed |
| GS | Small hail and/or snow pellets |
| 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 GLOSSARY OF TERMS | |
| H24 | Continuous day and night service |
| HAPI | Helicopter approach path indicator |
| HBN | Hazard beacon |
| HDG | Heading |
| HDF | High frequency direction-finding station |
| HEL | Helicopter |
| HF | High frequency (3 000 to 30 000 KHz) |
| HGT | Height or height above |
| HIRL | High intensity runway lights |
| HJ | Sunrise to sunset |
| HLDG | Holding |
| HM | Holding/racetrack |
| 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 directionfinding station (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 GLOSSARY OF TERMS | |
| IAC | Instrument approach chart |
| 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 |
| IC | Diamond dust (very small ice crystals in suspension) |
| 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 |
| 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 |
| IRS | Inertial reference system |
| ISA | International standard atmosphere |
| 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 GLOSSARY OF TERMS | |
| 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 GLOSSARY OF TERMS | |
| KG | Kilograms |
| KHz | Kilohertz |
| KM | Kilometres |
| KMH | Kilometres per hour |
| *KOP | Air Force |
| 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 GLOSSARY OF TERMS | |
| L | Left (runway identification) |
| L | Locator (see LM, LO) |
| LAM | Logical acknowledgement (message type designator) |
| LAN | Inland |
| LAT | Latitude |
| 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 | Local or locally or location or located |
| LOC | Localizer |
| LONG | Longitude |
| LORAN | LORAN (long range air navigation system) |
| LRG | Long range |
| LSQ | Line squall |
| LTD | Limited |
| LTT | Landline teletypewriter |
| LV | Light and variable (relating to wind) |
| LVE | Leave or leaving |
| LVL | Level |
| LVP | Low visibility procedures |
| 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 GLOSSARY OF TERMS | |
| M | Mach number (followed by figures) |
| M | Metres (preceded by figures) |
| MAA | Maximum authorized altitude |
| MAG | Magnetic |
| MAHF | Missed approach holding fix |
| MAINT | Maintenance |
| MAP | Aeronautical maps and charts |
| MAPT | Missed approach point |
| MAR | At sea |
| MAR | March |
| MATF | Missed approach turning fix |
| MAX | Maximum |
| MAY | May |
| 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 systems) |
| MET | Meteorological or meteorology |
| METAR | Aviation routine weather report (in aeronautical meteorological code) |
| MF | Medium frequency (300 to 3 000 KHz) |
| MHDF | Medium and high frequency direction-finding stations (at the same location) |
| MHVDF | Medium, high and very high frequency direction-finding stations (at the same location) |
| MHz | Megahertz |
| MID | Mid-point (related to RVR) |
| MID | Middle East |
| MIFG | Shallow fog |
| MIL | Military |
| MIN | Minutes |
| MKR | Marker radio beacon |
| MLS | Microwave landing system |
| 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 |
| 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 |
| MTU | Metric units |
| MTW | Mountain waves |
| MVDF | Medium and very high frequency direction finding stations (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 GLOSSARY OF TERMS | |
| N | North or northern latitude |
| N | No distinct tendency (in RVR during previous 10 minutes) |
| NAT | North Atlantic |
| NAV | Navigation |
| NB | Northbound |
| 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 I have nothing to send to you |
| NM | Nautical miles |
| NM | Network Manager/Management |
| NML | Normal |
| NMOC | Network Manager Operations Centre |
| 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 |
| NPA | Non-precision approach |
| *NPZ | No planning zone |
| 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 GLOSSARY OF TERMS | |
| 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 |
| OHD | Overhead |
| OM | Outer marker |
| OPA | Opaque, white type of ice formation |
| OPMET | Operational meteorological (information) |
| OPN | Open or opening or opened |
| OPR | Operator or operate or perative or operating or operational |
| OPS | Operations |
| O/R | On request |
| ORD | Indication of an order |
| OSV | Ocean station vessel |
| OTLK | Outlook (used in SIGMET messages for volcanic ash and tropical cyclones) |
| OTP | On top |
| OTS | Organized track system |
| OUBD | Outbound |
| 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 GLOSSARY OF TERMS | |
| P | Personal consultation |
| 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 |
| PAX | Passenger(s) |
| PCD | Proceed or proceeding |
| PCN | Pavement classification number |
| PDG | Procedure design gradient |
| PER | Performance |
| PERM | Permanent |
| PIB | Pre-flight information bulletin |
| PJE | Parachute jumping exercise |
| PL | Abbreviated plain language texts |
| PL | Ice pellets |
| 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 |
| PRI | Primary |
| PRKG | Parking |
| P-RNAV | Precision area navigation |
| PROB | Probability |
| PROC | Procedure |
| PROV | Provisional |
| PS | Plus |
| PSG | Passing |
| PSN | Position |
| PSP | Pierced steel plank |
| PSR | Primary surveillance radar |
| 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 GLOSSARY OF TERMS | |
| 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 GLOSSARY OF TERMS | |
| R | Red |
| R | Right (runway identification) |
| R... | Restricted area (followed by identification) |
| RA | Rain |
| RAC | Rules of the air and air traffic services |
| *RAD | Route Availability Document |
| RAFC | Regional area forecast centre |
| RAG | Ragged |
| RAG | Runway arresting gear |
| 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) |
| RCLM | Runway center line markings |
| RCLR | Recleared |
| RDH | Reference datum height (for ILS) |
| RDL | Radial (VOR) |
| 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 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 |
| RL | Runway lights |
| RLA | Relay to |
| RLCE | Request level change en route |
| RLLS | Runway lead-in lighting system |
| RLNA | Request 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 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) |
| RTIL | Runway threshold identification lights |
| 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 |
| RVSM | Reduced vertical separation minimum |
| 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 GLOSSARY OF TERMS | |
| S | Surface analysis (current chart) |
| S | South or southern latitude |
| SA | Sand |
| *SA | Special activity areas |
| 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 |
| SGZ | Special gliders zone |
| 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 |
| SIG | Significant |
| SIGMET | Information concerning en-route weather phenomena which may affect the safety of aircraft 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 |
| SOC | Start of climb |
| 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) |
| SPOT | Spot wind |
| SQ | Squall |
| 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 |
| SSE | South south east |
| SSR | Secondary surveillance radar |
| SST | Supersonic transport |
| SSW | South south west |
| 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 GLOSSARY OF TERMS | |
| T | Temperature |
| T(...T) | True (preceded by a bearing to indicate reference to True North) |
| TA | Transition altitude |
| TAA | Terminal arrival altitude |
| TACAN | UHF tactical air navigation aid |
| TAF | Aerodrome forecast |
| TAIL | Tail wind |
| TAR | Terminal area surveillance radar |
| TAS | True airspeed |
| TAX | Taxiing or taxi |
| TB | Tabular forms |
| TC | Tropical cyclone |
| TCH | Threshold crossing height |
| TCU | Towering cumulus |
| TDO | Tornado |
| TDZ | Touchdown zone |
| TECR | Technical reason |
| TEL | Telephone |
| TEMPO | Temporary or temporarily |
| TEND | Trend forecast |
| TF | Track to a fix |
| TFC | Traffic |
| TGL | Temporary Guidance Leaflef |
| TGL | Touch-and-go landing |
| TGM | Temporary Guidance Material |
| TGS | Taxiing guidance system |
| THR | Threshold |
| THRU | Through |
| THU | Thursday |
| TIA | Traffic information area |
| TIL | Until |
| TIP | Until past ... (place) |
| TIZ | Traffic information zone |
| 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 |
| TREND | Trend forecast |
| 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) |
| TSA | Temporary segregated area |
| 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 GLOSSARY OF TERMS | |
| 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 - 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 | Coordinated 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 GLOSSARY OF TERMS | |
| VA | Volcanic ash |
| VAC | Visual approach chart |
| 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, SH=showers, PO=dust/sand whirls, BLDU=blowingdust, 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 (30-300 MHz) |
| VIA | By way of... |
| 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 |
| *VSAT | State Border Guard Service |
| 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 GLOSSARY OF TERMS | |
| 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 |
| WGS | World geodetic system |
| 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 |
| WNW | West north west |
| WO | Without |
| WPT | Way-point |
| WRNG | Warning |
| WS | Wind shear |
| 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 GLOSSARY OF TERMS | |
| 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 GLOSSARY OF TERMS | |
| 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 GLOSSARY OF TERMS | |
| Z | Coordinated Universal Time (in meteorological messages) |