Aviation Abbreviations
142 abbreviations · part of Transportation & Travel Abbreviations
Abbreviations used by pilots, air traffic controllers, dispatchers, mechanics and aviation weather services, from flight rules (IFR, VFR) and navigation aids (VOR, ILS) to pilot certificates, aircraft systems, V-speeds and airline operations. Most follow ICAO or FAA conventions and appear on charts, NOTAMs, weather reports, logbooks and cockpit radio calls. Where US (FAA) and international (ICAO, EASA) usage differ, the entries say so.
| Abbreviation | Stands for | Description |
|---|---|---|
| A&P | Airframe and powerplant | FAA mechanic certificate with both airframe and powerplant ratings, authorizing the holder to maintain, repair and approve most civil aircraft for return to service. |
| ACARS | Aircraft Communications Addressing and Reporting System | Digital datalink that sends short text messages between aircraft and ground stations by VHF radio or satellite, carrying engine data, position reports, weather, gate… |
| ACC | Area control centre | ICAO term for the air traffic control unit responsible for en-route IFR flights within a flight information region, the equivalent of a US ARTCC. |
| ADF | Automatic direction finder | Cockpit radio receiver and bearing needle that points toward a tuned NDB or even a commercial AM broadcast station. |
| ADIZ | Air defense identification zone | Designated airspace, often extending well beyond a country's territorial waters, in which aircraft must identify themselves, file flight plans and report positions to… |
| ADS-B | Automatic Dependent Surveillance-Broadcast | Surveillance technology in which an aircraft determines its position by GPS and broadcasts it, with altitude, velocity and identity, about once per second to ground… |
| AGL | Above ground level | Height measured from the terrain directly below an aircraft rather than from sea level. |
| AIM | Aeronautical Information Manual | FAA guide explaining flight procedures, ATC phraseology, airspace, weather services and aeromedical facts for pilots. |
| AIRMET | Airmen's Meteorological Information | In-flight weather advisory for hazards most significant to small aircraft: moderate icing, moderate turbulence, sustained surface winds over 30 knots, widespread IFR… |
| AME | Aircraft maintenance engineer | Title for a licensed aircraft mechanic in Canada, Australia, the UK and many other countries, where the licence is often written LAME (licensed aircraft maintenance… |
| AOG | Aircraft on ground | Highest-priority maintenance status meaning an aircraft is grounded by a technical problem and cannot fly until a part or repair arrives. |
| AP | Autopilot | System that controls an aircraft's flight path automatically, holding heading, altitude, speed or a programmed route, and on airliners capable of flying an approach and… |
| APU | Auxiliary power unit | Small gas-turbine engine, usually in the tail cone of an airliner, supplying electrical power and compressed air for air conditioning and engine starting when the main… |
| ARTCC | Air Route Traffic Control Center | FAA facility that controls IFR aircraft in the en-route phase across a large region; about 20 centers cover the contiguous United States. |
| ASM | Available seat miles | Airline capacity measure equal to the number of seats flown multiplied by the miles flown, whether or not the seats are filled. |
| ASOS | Automated Surface Observing System | Network of more than 900 automated weather stations in the United States, mostly at airports, run jointly by the National Weather Service, the FAA and the Department of… |
| ATA | Actual time of arrival | Time at which an aircraft, ship or vehicle really arrived, recorded for comparison with the scheduled (STA) and estimated (ETA) times. |
| ATC | Air traffic control | Ground-based service that separates aircraft and keeps traffic moving safely on runways, taxiways and through controlled airspace. |
| ATD | Actual time of departure | Recorded time at which a flight or vessel actually left, as opposed to the scheduled or estimated time. |
| ATIS | Automatic Terminal Information Service | Continuous recorded broadcast at busier airports giving current weather, runways in use, approaches being flown and important NOTAMs. |
| ATP | Airline transport pilot | Highest level of FAA pilot certificate, required for both captains and first officers at US scheduled airlines. |
| ATPL | Airline transport pilot licence | Highest pilot licence under ICAO and EASA rules, required to command a multi-crew airliner. |
| AWOS | Automated Weather Observing System | Automated sensor suite at smaller airports that measures wind, visibility, cloud height, temperature, dew point and altimeter setting and broadcasts the results by… |
| BFR | Biennial flight review | Required refresher for US pilots consisting of at least one hour of ground instruction and one hour of flight instruction with a flight instructor every 24 calendar… |
| BVLOS | Beyond visual line of sight | Drone operation in which the remote pilot cannot see the aircraft directly, relying on cameras, detect-and-avoid systems and data links. |
| CASM | Cost per available seat mile | Airline unit cost: total operating expenses divided by available seat miles, quoted in cents. |
| CAVOK | Ceiling and visibility OK | Weather code used outside the United States when visibility is 10 kilometers or more, there is no cloud below 5,000 feet or the highest minimum sector altitude, no… |
| CFI | Certified flight instructor | Pilot holding an FAA flight instructor certificate, authorized to give flight and ground training and to endorse students for solo flights and checkrides. |
| CFII | Certified flight instructor - instrument | Flight instructor certificate with an instrument rating added, allowing the holder to teach instrument flying and endorse students for the instrument rating checkride. |
| CFIT | Controlled flight into terrain | Accident in which an airworthy aircraft under pilot control is unintentionally flown into the ground, water or an obstacle, usually because the crew lost awareness of… |
| CPDLC | Controller-pilot data link communications | Text messaging between air traffic controllers and flight crews, used for clearances, frequency changes and requests instead of voice radio. |
| CPL | Commercial pilot license | Pilot certificate allowing the holder to be paid for flying, for example banner towing, aerial photography, crop dusting or some charter work. |
| CRM | Crew resource management | Training and operating philosophy that teaches flight crews to communicate, share decisions and challenge errors rather than deferring to the captain. |
| CTAF | Common traffic advisory frequency | Radio frequency on which pilots at airports without an operating control tower announce their positions and intentions to one another. |
| CVR | Cockpit voice recorder | Crash-protected recorder capturing pilots' voices, radio calls, alarms and other cockpit sounds. |
| DA | Decision altitude | Altitude above mean sea level on a precision or vertically guided approach at which the pilot must either have the required runway references in sight to continue or… |
| DH | Decision height | Height above the runway threshold, normally read on a radio altimeter, at which a pilot on a Category II or III precision approach must decide to land or go around. |
| DME | Distance measuring equipment | Avionics system that measures slant-range distance in nautical miles between an aircraft and a ground station by timing paired UHF pulses. |
| DPE | Designated pilot examiner | Private individual authorized by the FAA to conduct practical tests, or checkrides, for pilot certificates and ratings on the agency's behalf. |
| EFB | Electronic flight bag | Tablet or installed computer that replaces paper charts, manuals and performance tables in the cockpit, running apps for navigation charts, weather and takeoff… |
| EGPWS | Enhanced ground proximity warning system | Terrain awareness system that compares the aircraft's GPS position with a worldwide terrain and obstacle database and issues forward-looking alerts such as "Terrain… |
| ELT | Emergency locator transmitter | Beacon in an aircraft that activates automatically in a crash and transmits a distress signal, on 406 MHz in modern units, to the Cospas-Sarsat satellite system so… |
| ETA | Estimated time of arrival | Predicted time at which an aircraft, ship, train, vehicle or parcel will reach its destination. |
| ETD | Estimated time of departure | Predicted time at which a flight, ship, train or other journey will leave, revised as delays develop. |
| ETE | Estimated time en route | Predicted flying time from departure to destination or to the next waypoint, calculated from distance, true airspeed and forecast winds. |
| ETOPS | Extended-range Twin-engine Operational Performance Standards | Rules allowing twin-engine airliners to fly routes taking them more than 60 minutes from a suitable diversion airport, such as across oceans, deserts or polar regions. |
| eVTOL | Electric vertical takeoff and landing aircraft | Battery-powered aircraft designed to take off and land vertically like a helicopter and cruise efficiently on wings or tilting rotors, developed as quiet urban air… |
| FA | Flight attendant | Cabin crew member responsible for passenger safety and service, trained in evacuations, firefighting, first aid and security. |
| FAF | Final approach fix | Fix from which the final segment of a nonprecision instrument approach begins, marked on US approach charts with a Maltese cross. |
| FAR | Federal Aviation Regulations | Rules issued by the FAA governing civil aviation in the United States, codified in Title 14 of the Code of Federal Regulations. |
| FBO | Fixed-base operator | Business at an airport that serves general aviation and private jets with fuel, parking, hangars, maintenance, pilot lounges and private passenger terminals. |
| FD | Flight director | Guidance display, usually magenta or green command bars on the attitude indicator, showing the pitch and roll needed to follow a selected path or mode. |
| FDR | Flight data recorder | Crash-protected recorder that logs hundreds or thousands of aircraft parameters, such as altitude, airspeed, heading, control positions and engine data, covering at… |
| FE | Flight engineer | Third crew member on older large aircraft such as the Boeing 727, early 747 models and the DC-10, responsible for monitoring and managing engines, fuel, hydraulics… |
| FIR | Flight information region | Block of airspace in which a designated authority provides flight information and alerting services, used by ICAO to divide the world's skies, including oceans. |
| FL | Flight level | Altitude expressed in hundreds of feet with the altimeter set to the standard pressure of 29.92 inches of mercury (1013.25 hectopascals), so FL350 is roughly 35,000 feet. |
| FMS | Flight management system | Onboard computer system that automates navigation, performance calculations and fuel predictions and can fly a programmed route laterally and vertically through the… |
| FO | First officer | Second pilot on an airliner, seated on the right and sharing flying duties with the captain, typically alternating legs as pilot flying and pilot monitoring. |
| FOD | Foreign object debris | Any loose object on a runway, taxiway or ramp, such as bolts, rocks, luggage tags or wildlife remains, that can be ingested by engines or puncture tires. |
| FSS | Flight service station | Air traffic facility that provides pilots with weather briefings, flight plan filing, NOTAMs and in-flight advisories but does not control traffic. |
| GA | General aviation | All civil flying other than scheduled airline and military operations, including private planes, flight training, business jets, air ambulances, crop dusters and… |
| GPU | Ground power unit | Cart or fixed gate system supplying a parked aircraft with electrical power, typically 115-volt, 400-hertz AC for airliners or 28-volt DC for smaller aircraft. |
| GS | Glideslope | ILS component that broadcasts a UHF signal defining the vertical descent path to the runway, typically at a 3-degree angle. |
| HSI | Horizontal situation indicator | Navigation instrument combining a heading indicator with a course deviation indicator, so the pilot sees heading and position relative to a selected VOR, localizer or… |
| HUD | Head-up display | Transparent screen in the pilot's line of sight that projects flight information, such as speed, altitude and flight path, over the outside view so the pilot need not… |
| IA | Inspection Authorization | FAA authorization added to an A&P mechanic certificate that allows the holder to perform annual inspections on general aviation aircraft and approve major repairs and… |
| IAP | Instrument approach procedure | Published series of maneuvers, fixes and altitudes that guides an aircraft under IFR from the en-route phase to a point where it can land or begin a missed approach. |
| IAS | Indicated airspeed | Speed shown on the airspeed indicator, derived from the difference between ram air pressure in the pitot tube and static pressure. |
| IATA | International Air Transport Association | Trade association of about 350 airlines, founded in 1945 and headquartered in Montreal with executive offices in Geneva, that sets industry standards for tickets… |
| ICAO | International Civil Aviation Organization | United Nations specialized agency, established by the 1944 Chicago Convention and based in Montreal, that sets global standards for air navigation, safety, airports… |
| IFE | In-flight entertainment | Movies, television, music, games and moving maps provided to passengers during a flight, either on seatback screens or streamed to personal devices. |
| IFR | Instrument flight rules | Regulations under which a pilot flies by reference to cockpit instruments and follows ATC clearances instead of navigating by outside visual cues. |
| ILS | Instrument landing system | Precision approach system in which two ground radio beams, the localizer for left-right guidance and the glideslope for vertical guidance, lead an aircraft down to the… |
| IMC | Instrument meteorological conditions | Weather below the minimums for visual flight, such as low cloud, fog or poor visibility, in which an aircraft may be flown only under IFR by an instrument-rated pilot. |
| IR | Instrument rating | Pilot rating authorizing flight under IFR, including in clouds and low visibility. |
| LAANC | Low Altitude Authorization and Notification Capability | FAA system giving drone pilots near-instant authorization to fly in controlled airspace near airports, through approved apps, up to the altitude limits shown on UAS… |
| LCC | Low-cost carrier | Airline business model built on low base fares, high aircraft utilization, a single aircraft type, point-to-point routes and fees for extras such as checked bags and… |
| LIFR | Low instrument flight rules | Weather category for the poorest conditions: ceilings below 500 feet or visibility less than 1 statute mile. |
| LOC | Localizer | ILS component that transmits a VHF signal aligned with the runway centerline, giving pilots lateral guidance on approach. |
| LPV | Localizer performance with vertical guidance | Highest-precision line of minimums on a GPS approach in the United States, using WAAS to provide ILS-like lateral and vertical guidance down to as low as 200 feet above… |
| LSA | Light-sport aircraft | US category of small, simple aircraft that can be flown with a sport pilot certificate using a driver's license instead of an FAA medical certificate. |
| MAP | Missed approach point | Point on an instrument approach at which a pilot who cannot see the runway must begin the published missed approach procedure. |
| MDA | Minimum descent altitude | Lowest altitude to which a pilot may descend on a nonprecision approach, such as a VOR or LNAV approach, without seeing the runway environment. |
| MEI | Multiengine instructor | Flight instructor rating authorizing the holder to teach in airplanes with more than one engine, including engine-failure procedures that keep the aircraft under… |
| MEL | Minimum equipment list | Approved list of aircraft equipment that may be inoperative for a flight, with the conditions, time limits and procedures for dispatching anyway. |
| METAR | Meteorological Aerodrome Report | Coded routine weather observation for an airport, issued at least hourly and more often when conditions change, giving wind, visibility, present weather, cloud layers… |
| MFD | Multi-function display | Cockpit screen that can show navigation maps, engine data, weather, traffic, terrain, checklists and charts at the pilot's choice. |
| MRO | Maintenance, repair and overhaul | Aviation industry sector servicing aircraft, engines and components, from routine line checks to heavy C- and D-checks. |
| MSL | Mean sea level | Average level of the ocean surface, used as the reference for aircraft altitudes, airport elevations and terrain heights on aeronautical charts. |
| MTOW | Maximum takeoff weight | Heaviest weight at which an aircraft is certified to begin its takeoff roll, set by structural and performance limits. |
| MVFR | Marginal visual flight rules | Flight category for ceilings from 1,000 to 3,000 feet or visibility from 3 to 5 statute miles. |
| NDB | Non-directional beacon | Low- or medium-frequency radio transmitter sending a signal in all directions, which a cockpit automatic direction finder uses to point toward the station. |
| NOTAM | Notice to Air Missions | Time-critical notice about a change in the aviation system, such as a closed runway, an inoperative navigation aid, a crane near an approach path or a temporary flight… |
| PAPI | Precision approach path indicator | Row of usually four lights beside the runway that shows whether an approaching aircraft is on the correct glide path: two white and two red means on path, more white… |
| PAX | Passengers | Industry shorthand for passengers, used by airlines, airports, cruise lines, ferry operators and tour companies in load reports, manifests and planning. |
| PFD | Primary flight display | Main screen in a glass cockpit, combining the attitude indicator, airspeed and altitude tapes, vertical speed, heading and autopilot mode annunciations on one display. |
| PIC | Pilot in command | Pilot with final authority over and responsibility for the operation and safety of a flight, designated before it begins. |
| PIREP | Pilot report | Report of actual in-flight weather passed by a pilot to ATC or flight service, describing turbulence, icing, cloud tops, wind shear or other conditions. |
| POH | Pilot's operating handbook | Manufacturer's manual for a specific aircraft model, containing limitations, normal and emergency procedures, performance charts, weight-and-balance data and systems… |
| PPL | Private pilot license | Entry-level pilot certificate allowing the holder to carry passengers and fly for personal purposes, but not for compensation or hire. |
| QFE | Altimeter setting giving height above the airfield (Q code) | Pressure setting that makes the altimeter read zero on the runway, so in flight it shows height above the airfield rather than above sea level. |
| QNH | Altimeter setting giving altitude above mean sea level (Q code) | Local pressure setting that makes the altimeter read the airport's elevation when on the ground and altitude above mean sea level in flight. |
| RA | Resolution advisory | TCAS command telling pilots to climb, descend or adjust vertical speed to avoid a potential collision, issued roughly 15 to 35 seconds before closest approach depending… |
| RNAV | Area navigation | Navigation method allowing an aircraft to fly any desired path between waypoints rather than only directly to or from ground beacons. |
| RNP | Required navigation performance | Navigation specification requiring an aircraft to stay within a set distance of its intended path and to alert the crew when that accuracy cannot be assured. |
| RPM | Revenue passenger miles | Airline traffic measure equal to the number of paying passengers multiplied by the miles they fly; one paying passenger flown one mile is one RPM. |
| RVR | Runway visual range | Instrument-measured distance a pilot on the runway centerline can see runway lights or markings, reported in feet in the US and meters elsewhere. |
| RVSM | Reduced vertical separation minimum | Airspace standard that cuts the vertical separation between IFR aircraft from 2,000 feet to 1,000 feet between FL290 and FL410, adding six usable cruising levels. |
| SEL | Single-engine land | Aircraft class rating for airplanes with one engine that operate from land, the rating most private pilots hold. |
| SIC | Second in command | Pilot designated to assist or relieve the pilot in command, usually the first officer on an airliner or business jet. |
| SID | Standard instrument departure | Published IFR departure procedure that routes aircraft from the runway into the en-route structure along fixed headings, waypoints and altitudes, simplifying clearances… |
| SIGMET | Significant meteorological information | Aviation weather advisory warning all aircraft of hazards such as severe turbulence, severe icing, volcanic ash, dust storms or widespread thunderstorms. |
| STA | Scheduled time of arrival | Timetabled arrival time of a flight, train or ship, used as the baseline for measuring delays. |
| STAR | Standard terminal arrival route | Published IFR arrival procedure linking the en-route airways to an airport's approach phase, with defined waypoints and altitude and speed restrictions. |
| STD | Scheduled time of departure | Published departure time of a flight, train or ship as shown in the timetable and on the ticket. |
| STOL | Short takeoff and landing | Capability of an aircraft to operate from very short runways thanks to high-lift wings, flaps, slats and ample power. |
| SVFR | Special visual flight rules | ATC clearance letting a VFR pilot operate in the controlled airspace around an airport when weather is below normal VFR minimums, provided there is at least 1 statute… |
| TA | Traffic advisory | TCAS caution, announced as "Traffic, traffic," indicating that another aircraft may become a collision threat, typically 20 to 48 seconds before closest approach. |
| TAF | Terminal Aerodrome Forecast | Coded aviation weather forecast for the area within about 5 statute miles of an airport, usually covering 24 or 30 hours and issued four times a day. |
| TAS | True airspeed | Actual speed of an aircraft through the surrounding air mass, obtained by correcting calibrated airspeed for altitude and temperature. |
| TCAS | Traffic alert and collision avoidance system | Onboard system that interrogates other aircraft's transponders, displays nearby traffic and, if a collision threat develops, issues spoken commands such as "Climb… |
| TFR | Temporary flight restriction | Airspace temporarily closed or restricted to most aircraft, announced by NOTAM, around events such as presidential travel, wildfires, space launches, disaster areas and… |
| TRACON | Terminal radar approach control | ATC facility that handles aircraft arriving at and departing from one or more busy airports, typically within 30 to 50 nautical miles and up to around 17,000 feet. |
| TSA PreCheck | Transportation Security Administration PreCheck | US trusted-traveler program that lets preapproved low-risk travelers use expedited airport security lanes where they keep shoes, belts and light jackets on and leave… |
| UAS | Unmanned aircraft system | Drone together with its ground control station, data links and support equipment. |
| UAV | Unmanned aerial vehicle | Aircraft without a pilot on board, flown remotely or autonomously, ranging from hand-launched quadcopters to large armed drones such as the MQ-9 Reaper. |
| ULCC | Ultra-low-cost carrier | Airline that pushes the low-cost model further, offering the lowest base fares and charging separately for nearly everything else, including carry-on bags, seat… |
| UNICOM | Universal communications | Nongovernment air-ground radio station at an airport, usually run by the FBO or airport operator, that gives pilots information such as the favored runway, fuel… |
| V1 | Takeoff decision speed | Speed on the takeoff roll beyond which the crew must continue the takeoff even if an engine fails, because there is no longer enough runway to stop safely. |
| V2 | Takeoff safety speed | Minimum speed an airliner must reach by 35 feet above the runway and hold during the initial climb with one engine inoperative, ensuring adequate climb performance and… |
| VASI | Visual approach slope indicator | Older visual glide-path system using bars of lights near the runway threshold: when the aircraft is on the correct path, the near bar shows white and the far bar shows… |
| VFR | Visual flight rules | Regulations allowing a pilot to fly by looking outside, navigating by landmarks and avoiding other aircraft by sight. |
| VMC | Visual meteorological conditions | Weather with visibility and cloud clearances at or above the minimums for flight under visual flight rules. |
| Vne | Never-exceed speed | Maximum airspeed for a light aircraft, beyond which flutter or structural failure may occur, marked by a red radial line on the airspeed indicator. |
| VOR | VHF omnidirectional range | Ground radio beacon that transmits 360 radials, letting an aircraft determine its magnetic bearing from the station. |
| VORTAC | VOR combined with TACAN (tactical air navigation) | Navigation station that colocates a civil VOR with a military TACAN, giving civilian aircraft bearing information plus distance through the TACAN's DME function. |
| VR | Rotation speed | Speed at which the pilot raises the nosewheel to lift the aircraft off the runway, called "rotate" by the monitoring pilot. |
| Vref | Reference landing speed | Speed at which an airliner crosses the runway threshold in landing configuration, at least 1.23 times the stall speed, with additives for gusty winds. |
| VTOL | Vertical takeoff and landing | Ability of an aircraft to take off and land vertically, as helicopters, the V-22 Osprey tiltrotor and the Harrier jump jet can, without a runway. |
| Vx | Best angle of climb speed | Airspeed giving the greatest altitude gain over a given horizontal distance, used to clear obstacles after a short-field takeoff. |
| Vy | Best rate of climb speed | Airspeed giving the greatest altitude gain per unit of time, used for normal climbs once obstacles are cleared. |
| WAAS | Wide Area Augmentation System | FAA satellite-based augmentation system that corrects GPS signals using a network of ground reference stations and geostationary satellites, improving accuracy to a few… |