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.
| 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 |
| *AA | Approved Agency |
| AAA | (or AAB, AAC...etc., in sequence) Amended meteorological message (message type designator) |
| A/A | Air to Air |
| AAD | Assigned altitude deviation |
| AAL | Above aerodrome level |
| ABM | Abeam |
| ABN | Aerodrome beacon |
| ABT | About |
| ABV | Above |
| AC | Altocumulus |
| ACARS | (to be pronounced “AY-CARS”) 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 |
| 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 (to be used in AFS as a procedure signal) |
| 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 | Aerodromes, air routes and ground aids |
| AGL | Above ground level |
| AGN | Again |
| AIC | Aeronautical information circular |
| AIDC | Air traffic services inter-facility 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 | Aeronautical 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 |
| AOC | Aerodrome obstacle chart (followed by type and name/title) |
| *AoR | Area of Responsibility |
| AP | Airport |
| APAPI | (to be pronounced “AY-PAPI”) 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 |
| APV | Approve or approved or approval |
| *APV | Approach procedure with vertical guidance |
| *AR | Authorization Required |
| ARC | Area chart |
| *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 | 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 | Ascend 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 operations |
| *A-SMGCS | Advanced Surface Movement Guidance and Control System |
| 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) ‡ |
| *ATCC | Air traffic control centre |
| 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 | (to be pronounced “AY-TEE-VASIS”) Abbreviated T visual approach slope indicator system † |
| ATZ | Aerodrome traffic zone |
| AUG | August |
| *AUP | Airspace use plan |
| AUTH | Authorized or authorization |
| AUW | All up weight |
| AUX | Auxiliary |
| 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 GLOSSARY OF TERMS | |
| B | Blue |
| BA | Braking action |
| BARO-VNAV | (to be pronounced “BAA-RO-VEE-NAV”) Barometric vertical navigation † |
| BASE | Cloud base † |
| BCFG | Fog patches |
| BCN | Beacon (aeronautical ground light) |
| BCST | Broadcast |
| BDRY | Boundary |
| BECMG | Becoming |
| BFR | Before |
| BKN | Broken (cloud amount 5-7 octas) |
| 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 GLOSSARY OF TERMS | |
| 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 | Coordination (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 procedure 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) |
| CHG | Modification (message type designator) |
| CI | Cirrus |
| CIDIN | Common ICAO data interchange network † |
| *CIS | Common Information Service |
| *CISP | Common Information Service Provider |
| 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 |
| *CLL | Center line lights |
| CLR | Clear(s) or cleared to ... or clearance |
| CLRD | Runway(s) cleared (used in METAR/SPECI) |
| 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 | Coordinate 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 |
| 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 |
| *CTOT | Calculated Take-Off Time (departure slot) |
| 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 GLOSSARY OF TERMS | |
| D | Downward (tendency in RVR during previous 10 minutes) |
| D... | Danger area (followed by identification) |
| DA | Decision altitude |
| *D-AMA | Danger AMC manageable area |
| D-ATIS | (to be pronounced “DEE-ATIS”) Data link automatic terminal information service † |
| DCD | Double channel duplex |
| DCKG | Docking |
| 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 od 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) |
| DER | Departure end of runway |
| DES | Descend to or descending to |
| DEST | Destination |
| DETRESFA | Distress phase † |
| DEV | Deviation or deviating |
| DF | Direction finding |
| *DF | Direct to fix |
| DFDR | Digital flight data recorder |
| DFTI | Distance from touchdown indicator |
| DH | Decision height |
| DIF | Diffuse |
| DIST | Distance |
| DIV | Divert or diverting |
| DLA | Delay or delayed |
| DLA | Delay (message type designator) |
| DLIC | Data link initiation capability |
| DLY | Daily |
| 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 | Dust storm |
| 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 |
| D-VOLMET | Data link VOLMET |
| 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 |
| EEE | Error (to be used in AFS as a procedure signal) |
| EET | Estimated elapsed time |
| EFC | Expect further clearance |
| EFIS | (to be pronounced “EE-FIS”) Electronic flight instrument system † |
| eFPL | Filed flight plan exchanged via flight and flow — information for a collaborative environment (FF-ICE) services |
| EGNOS | (to be pronounced “EGG-NOS”) 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 |
| 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 |
| EQN | Equatorial latitudes northern hemisphere |
| EQPT | Equipment |
| EQS | Equatorial latitudes southern hemisphere |
| ER | Here or herewith |
| ESE | East-south-east |
| EST | Estimate or estimated or estimation (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 |
| *EXIT | Exit/turnoff taxiway |
| 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 |
| FA | Course from a fix to an altitude |
| 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 |
| FEW | Few (cloud amount 1-2 octas) |
| 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 |
| *FLOS | Flight Level Orientation Scheme |
| FLR | Flares |
| FLT | Flight |
| FLTCK | Flight check |
| FLUC | Fluctuating or fluctuation or fluctuated |
| FLW | Follow(s) or following |
| FLY | Fly or flying |
| FM | Course from a fix to manual termination (used in navigation database coding) |
| FM | From |
| FM... | From (followed by time weather change is forecast to begin) |
| FMC | Flight management computer |
| FMS | Flight management system ‡ |
| FMU | Flow management unit |
| FNA | Final approach |
| FPAP | Flight path alignment point |
| FPL | Filed flight plan exchanged via aeronautical fixed service (AFS) |
| 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 station |
| FST | First |
| FT | Feet (dimensional unit) |
| FTP | Fictitious threshold point |
| FTE | Flight technical error |
| 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 GLOSSARY OF TERMS | |
| G | Green |
| GA | Go ahead, resume sending (to be used in AFS as a procedure signal) |
| G/A | Ground-to-air |
| G/A/G | Ground-to-air and air-to-ground |
| GAMET | Area forecast for low-level flights |
| GCA | Ground controlled approach system or ground controlled approach ‡ |
| GEN | General |
| GEO | Geographic or true |
| GES | Ground earth station |
| GLD | Glider |
| GMC... | Ground movement chart (followed by name/title) |
| GND | Ground |
| GNDCK | Ground check |
| *GNDTWY | Ground taxiway |
| GNSS | Global navigation satellite system ‡ |
| GP | Glide path |
| GPA | Glide path angle |
| GPS | Global positioning system ‡ |
| GPWS | Ground proximity warning system ‡ |
| GR | Hail |
| GRASS | Grass landing area |
| GRIB | Processed meteorological data in the form of grid point values expressed in binary form (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 | |
| H | High pressure area or the centre of high pressure |
| H24 | Continuous day and night service |
| HA | Holding/racetrack to an altitude |
| *HAL | Horizontal alarm limit |
| HAPI | Helicopter approach path indicator |
| HBN | Hazard beacon |
| HDF | High frequency direction-finding station |
| HDG | Heading |
| HEL | Helicopter |
| HF | High frequency [3000 to 30 000 kHz]‡ |
| HF | Holding/racetrack to a fix |
| HGT | Height or height above |
| HJ | Sunrise to sunset |
| HLDG | Holding |
| HM | Holding/racetrack to a manual termination |
| HN | Sunset to sunrise |
| HNH | High latitudes northern hemisphere |
| HO | Service available to meet operational requirements |
| HOL | Holiday |
| HOSP | Hospital aircraft |
| HPA | Hectopascal |
| HR | Hours |
| HS | Service available during hours of scheduled operations |
| HSH | High latitudes southern hemisphere |
| 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 GLOSSARY OF TERMS | |
| 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 airspeed |
| IBN | Identification beacon |
| IC | Ice crystals (very small ice crystals in suspension, also known as diamond dust) |
| ICE | Icing |
| ID | Identifier or identify |
| IDENT | Identification † |
| IF | Intermediate approach fix |
| *IF | Initial fix |
| IFF | Identification friend/foe |
| 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 |
| *IRU | Inertial reference unit |
| 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 GLOSSARY OF TERMS | |
| *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 GLOSSARY OF TERMS | |
| KG | Kilograms |
| KHZ | Kilohertz |
| KIAS | Knots indicated airspeed |
| 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 GLOSSARY OF TERMS | |
| L | Left (preceded by runway designation number to identify a parallel runway) |
| L | Locator (see LM, LO) |
| L | Low pressure area or the centre of low pressure |
| *LAL | Lowest Available Level (within SECSI FRA) |
| 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 (to be pronounced “EL-NAV”) † |
| LNG | Long (used to indicate the type of approach desired or required) |
| LO | Locator, outer |
| *LoA | Letters of agreement |
| LOC | Localizer |
| LONG | Longitude |
| LORAN | LORAN (long range air navigation system) † |
| 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) |
| LTD | Limited |
| LTP | Landing threshold point |
| LTT | Landline teletypewriter |
| LV | Light and variable (relating to wind) |
| LVE | Leave or leaving |
| LVL | Level |
| *LVO | Low Visibility Operations |
| LVP | Low visibility procedures |
| *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 GLOSSARY OF TERMS | |
| M | Metres (preceded by figures) |
| M | Mach number (followed 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 | At sea |
| MAR | March |
| MAS | Manual A1 simplex |
| MATF | Missed approach turning fix |
| MAX | Maximum |
| MAY | May |
| 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 systems) |
| MET | Meteorological or meteorology † |
| METAR | Aerodrome routine meteorological report (in meteorological code) † |
| MET REPORT | Local routine meteorological report (in abbreviated plain language) |
| 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) |
| 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 |
| MNH | Middle latitudes northern hemisphere |
| 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 † |
| 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 |
| MSAW | Minimum safe altitude warning |
| MSG | Message |
| MSH | Middle latitudes southern hemisphere |
| 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 |
| *MTOM | Maximum take-off mass |
| *MTOW | Maximum take-off weight |
| 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 | No distinct tendency (in RVR during previous 10 minutes) |
| N | North or northern latitude |
| NADP | Noise abatement departure procedure |
| NASC | National AIS system centre † |
| NAT | North Atlantic |
| NAV | Navigation |
| NB | Northbound |
| 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 |
| NGT | Night |
| NIL | None or I have nothing to send to you† |
| NM | Nautical miles |
| NML | Normal |
| NNE | North-north-east |
| NNW | North-north-west |
| NO | No (negative) (to be used in AFS as a procedure signal) |
| NOF | International NOTAM office |
| *NONFUA | Non-flexible use of airspace |
| NOSIG | No significant change (used in trend-type landing forecast) † |
| NOTAM | A notice distributed by means of telecommunication 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 |
| NSE | Navigation system error |
| NSW | Nil significant weather |
| NTL | National |
| NTZ | No transgression zone |
| *NUP | National Airspace Use Plan |
| 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 |
| 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) |
| OM | Outer marker |
| OPA | Opaque, white type of ice formation |
| OPC | 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 | Order |
| OSV | Ocean station vessel |
| 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... | 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 ‡ |
| *PAR | Parallel taxiway |
| 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 |
| PDC | Pre-departure clearance ‡ |
| PDG | Procedure design gradient |
| PER | Performance |
| PERM | Permanent |
| PFP | Preliminary flight plan |
| 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 |
| 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 GLOSSARY OF TERMS | |
| QDM | Magnetic heading (zero wind) ‡ |
| QDR | Magnetic bearing |
| QFE | Atmospheric pressure at aerodrome elevation (or at runway threshold); altimeter sub-scale setting to read a hight of zero when on the ground ‡ |
| 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) |
| QJH | Shall I run my test tape/a test sentence? or Run your test tape/a test sentence (to be used in AFS as a Q Code) |
| QNH | Atmospheric pressure at mean see level determined for standard atmosphere; Altimeter sub-scale setting to obtain elevation when on the ground ‡ |
| QSP | Will you relay to...free of charge? or I will relay to...free of charge (to be used in AFS as a Q code) |
| QTA | Shall I cancel channel sequence number...? or Cancel channel sequence 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 GLOSSARY OF TERMS | |
| R | Right (preceded by runway designation number to identify a parallel runway) |
| R | Red |
| R | Received (acknowledgement of receipt) (to be used in AFS as a procedure signal) |
| R... | Restricted area (followed by identification) |
| R... | Runway (followed by figures in METAR/SPECI) |
| *R | Radial (followed by magnetic bearing) |
| 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 |
| RAG | Runway arresting gear |
| 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 coordination 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 |
| 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 | Re-route |
| RESA | Runway end safety area |
| RF | Constant radius arc to a fix |
| 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 | Request level not available |
| RMK | Remark |
| 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 meteorological code) |
| RON | Receiving only |
| RPI | Radar position indicator ‡ |
| 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 |
| 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 ‡ |
| RVSM | Reduced vertical separation minimum (300 m (1 000 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 GLOSSARY OF TERMS | |
| S | South or southern latitude |
| S... | State of the sea (followed by figures in METAR/SPECI) |
| 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 |
| SBAS | (to be pronounced “ESS-BAS”) 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 |
| *SECSI | South East Common Sky Initiative |
| *SECSI FRA | South East Common Sky Initiative Free Route Airspace |
| 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... | Shower (followed by RA=rain, SN=snow, PL=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 |
| SNOCLO | Aerodrome closed due to snow (used in METAR/SPECI) |
| SNOWTAM | 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 |
| *SPEC | Specification |
| SPECI | Aerodrome special meteorological report (in meteorological code) † |
| SPECIAL | Local special meteorological report (in abbreviated plain language) † |
| SPI | Special position indicator |
| SPL | Supplementary flight plan (message type designator) |
| SPOC | SAR point of 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-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 |
| *STUB | Stub taxiway |
| 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 |
| SWX | Space weather |
| SWXC | Space weather centre |
| 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 |
| TA | Traffic advisory |
| TA | Transition altitude |
| TAA | Terminal arrival altitude |
| TACAN | UHF tactical air navigation aid † |
| TAF | Aerodrome forecast (in meteorological code) † |
| TA/H | Turn at an altitude/height |
| TAIL | Tail wind † |
| TAR | Terminal area surveillance radar |
| T-AROUND* | Turn around taxiway |
| TAS | True airspeed |
| TAX | Taxiing or taxi |
| TC | Tropical cyclone |
| TCAC | Tropical cyclone advisory centre |
| *TCH | Threshold crossing height |
| 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 |
| *TGL | Temporary Guidance Leaflet |
| 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 ‡ |
| 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 |
| TP | Turning point |
| TR | Track |
| TRA | Temporary reserved airspace |
| *TRA | Temporary reserved area |
| TRANS | Transmits or transmitter |
| TREND | Trend forecast † |
| 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, PL=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 | (to be pronounced “TEE-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) |
| 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 GLOSSARY OF TERMS | |
| U | Upward (tendency in RVR during previous 10 minutes) |
| UAB... | Until advised by ... |
| UAC | Upper area control centre |
| *UAG | UAS Approved Geographical Zone |
| 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 ‡ |
| *ULG | UAS Limited Geographical Zone |
| ULR | Ultra long range |
| UNA | Unable |
| UNAP | Unable to approve |
| UNL | Unlimited |
| UNREL | Unreliable |
| UP | Unidentified precipitation (used in automated METAR/SPECI) |
| *URG | UAS Restricted Geographical Zone |
| U/S | Unserviceable |
| *USSP | U-Space Service Provider |
| UTA | Upper control area |
| UTC | Coordinated Universal Time ‡ |
| *UTCW | UTC adjustable for summer time: the hours are expressed in UTC, as applicable during the winter time. During the summer time the values must be decreased by one hour |
| *UTR | UAS Temporary Reserved Area |
| *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 GLOSSARY OF TERMS | |
| V... | Variations from the mean wind direction (preceded and followed by figures in METAR/SPECI, e.g. 350V070) |
| VA | Heading to an altitude |
| VA | Volcanic ash |
| VAC... | Visual approach chart (followed by name/title) |
| VAL | In valleys |
| *VAL | Vertical alarm limit |
| VAN | Runway control van |
| VAR | Magnetic variation |
| VAR | Visual-aural radio range |
| VASIS | Visual approach slope indicator systems |
| VC... | Vicinity of the aerodrome (followed by FG=fog, FC=funnel cloud, SH=shower, PO=dust/sand whirl, BLDU=blowing dust, BLSA=blowing sand, BLSN=blowing snow, DS=duststorm, SS=sandstorm, TS=thunderstorm or VA=volcanic ash, 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]‡ |
| VI | Heading to an intercept |
| VIP | Very important person ‡ |
| VIS | Visibility |
| VLF | Very low frequency [3 to 30 kHz] |
| VLR | Very long range |
| VM | Heading to a manual termination |
| VMC | Visual meteorological conditions ‡ |
| VNAV | Vertical navigation † |
| *VOC | Visual Operation Chart |
| 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 |
| VRB | Variable |
| VSA | By visual reference to the ground |
| VSP | Vertical speed |
| 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 GLOSSARY OF TERMS | |
| 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 |
| 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 - 1984 |
| WI | Within |
| WID | Width or wide |
| WIE | With immediate effect or effective immediately |
| WILCO | Will comply † |
| WIND | Wind |
| 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 |
| WSPD | Wind speed |
| WSW | West-south-west |
| WT | Weight |
| WTSPT | Waterspout |
| WWW | Worldwide web |
| 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) |
| 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 GLOSSARY OF TERMS | |
| Z | Coordinated Universal Time (in meteorological messages) |