VFR Pilot Glossary
Clear explanations of the terms VFR pilots meet in weather briefings, airspace, flight planning, radio and licensing — in English and German.
A
- Airspace classes (C, D, E, G)Airspace & rulesEuropean airspace is divided into classes A to G. VFR flights typically use C, D, E and G: C and D require an ATC clearance, E does not for VFR, and G is uncontrolled.
- Alternate aerodromeFlight planningAn alternate aerodrome is a field you can divert to if landing at the destination is not possible or not advisable, for example because of weather, a closed runway or a fuel problem.
- Angle of attack (AoA)Flight planningAngle of attack is the angle between the wing’s chord line and the relative airflow. It is not the same as pitch attitude or the angle of the flight path above the horizon.
C
- CAVOK (ceiling and visibility OK)WeatherCAVOK means visibility is at least 10 km, no significant weather is reported, and specified cloud criteria are met. It does not mean the sky is cloudless or the whole route is safe for VFR.
- Ceiling (cloud base)WeatherThe ceiling is the height of the lowest cloud layer covering more than half the sky (BKN or OVC) below 20,000 ft. It is one of the key limits for VFR flights.
- Compulsory reporting pointRadio & navigationA compulsory reporting point is a published position, often a landmark, where VFR pilots must report to ATC or the aerodrome. Reporting points are named by letters such as November or Whiskey.
- Crosswind componentWeatherThe crosswind component is the part of the wind blowing across the runway. It equals wind speed × sine of the angle between wind and runway direction.
- CTR (control zone)Airspace & rulesA control zone is controlled airspace around an aerodrome that extends upwards from the surface. VFR flights need an ATC clearance to enter.
D
- Density altitudeWeatherDensity altitude is the altitude in the standard atmosphere at which air has the same density as the actual air. High temperature, high elevation and low pressure raise it and reduce aircraft performance.
- Dew pointWeatherThe dew point is the temperature to which air must cool to become saturated. A small spread between temperature and dew point signals a risk of fog, mist or low cloud.
F
- Flight time (block time)Licence & logbookFor aeroplanes, EASA flight time is measured from the moment the aircraft first moves to take off until it comes to rest after landing. It is the basis for logbook entries and licence requirements.
- Flight visibilityWeatherVisibility is how far prominent objects can be seen. For VFR in Europe, SERA.5001 generally requires 8 km at and above FL100 and 5 km below FL100 in airspace classes C to G.
- Fuel reserve (VFR)Flight planningFor VFR aeroplane flights by day, Part-NCO requires enough fuel to reach the destination plus a final reserve of at least 30 minutes at normal cruising altitude; at night, at least 45 minutes.
G
- GAFOR (General Aviation Forecast)WeatherGAFOR is a forecast for general aviation that classifies expected visibility and cloud-base conditions in defined regions or routes. It helps assess the broad weather situation for a VFR flight.
- Groundspeed (GS)Flight planningGroundspeed is the aircraft’s speed relative to the Earth’s surface. It determines how quickly you cover a route, not how much airflow the wing experiences.
I
- Indicated airspeed (IAS)Flight planningIAS is the speed shown on the aircraft’s airspeed indicator, before correction for instrument and position errors. It is not the aircraft’s speed over the ground.
- ICAO spelling alphabetRadio & navigationThe ICAO spelling alphabet assigns an internationally agreed codeword to each letter. Pilots and controllers use it to make callsigns, reporting points and other letter groups unambiguous over the radio.
L
M
- Magnetic variation (declination)Radio & navigationMagnetic variation is the angle between true north and magnetic north at a location. It is different from compass deviation, which is caused by magnetic influences within the aircraft.
- METAR (aerodrome routine weather report)WeatherA METAR is a coded, observed weather report for an aerodrome, usually issued every 30 or 60 minutes. It states wind, visibility, weather, cloud, temperature, dew point and QNH.
- Minimum height (VFR)Airspace & rulesUnder SERA.5005(f), VFR flights must fly at least 1,000 ft above the highest obstacle within 600 m over congested areas, and at least 500 ft above ground or water elsewhere — except for take-off and landing.
- Maximum take-off weight (MTOW)Flight planningMTOW is the maximum permitted aircraft weight at take-off. European documents often use maximum take-off mass (MTOM); the applicable limit is stated in the aircraft’s approved flight manual.
N
- Navigation log (PLOG)Flight planningA navigation log is the written plan for a VFR flight: legs, headings, distances, times, altitudes, frequencies and fuel. It is the reference you fly with and update en route.
- NOTAM (notice to airmen)Flight planningA NOTAM is an official notice about temporary changes relevant to flight, such as closed runways, restricted areas, unserviceable navaids or obstacles.
P
- Passenger recency (90-day rule)Licence & logbookUnder FCL.060, you may only carry passengers as PIC if you have made at least 3 take-offs, approaches and landings as sole manipulator of the controls in the preceding 90 days, in an aircraft of the same type or class.
- PPL(A) (private pilot licence – aeroplanes)Licence & logbookThe PPL(A) is the EASA private pilot licence for aeroplanes. Training requires at least 45 hours of flight instruction, including 25 hours dual and 10 hours supervised solo.
Q
- QFE (altimeter setting to aerodrome level)WeatherQFE is the pressure setting that makes the altimeter read zero on the runway. With QFE set, the altimeter shows height above the aerodrome.
- QNH (altimeter setting to mean sea level)WeatherQNH is the pressure setting that makes the altimeter show the aerodrome elevation above mean sea level when the aircraft is on the ground. With QNH set, the altimeter reads altitude.
R
S
- SEP class rating (single-engine piston)Licence & logbookThe SEP(land) class rating is valid for 24 months. It can be revalidated by experience: within the 12 months before expiry, 12 hours of flight time including 6 as PIC, 12 take-offs and landings, and a 1-hour training flight with an instructor.
- SIGMET (significant meteorological information)WeatherA SIGMET warns of specified observed or forecast en-route weather phenomena that may affect aircraft safety. The message defines the affected area, levels and validity period.
- Squawk (transponder code)Radio & navigationA squawk is the four-digit transponder code assigned by ATC or set by the pilot. In most of Europe, VFR flights without an assigned code squawk 7000.
- Stall (aerodynamic)Flight planningAn aerodynamic stall occurs when a wing exceeds its critical angle of attack and airflow separation reduces lift. It is not an engine stoppage and can occur at different airspeeds.
T
- Transition altitude (TA)Airspace & rulesTransition altitude is the altitude at or below which vertical position is expressed as altitude using QNH. Above the transition altitude during a climb, the altimeter is set to standard pressure, 1013.25 hPa, and position is expressed as a flight level.
- TAF (terminal aerodrome forecast)WeatherA TAF is a coded weather forecast for an aerodrome, typically valid for 9 to 30 hours. It uses change groups such as BECMG, TEMPO and PROB to describe expected developments.
- True airspeed (TAS)Flight planningTAS is the aircraft’s actual speed relative to the surrounding air mass. It is used with wind to calculate groundspeed, headings and flight times.
- TMZ (transponder mandatory zone)Airspace & rulesA TMZ is airspace in which aircraft must carry and operate a pressure-altitude-reporting transponder. It makes VFR traffic visible to ATC and collision-avoidance systems.
- Traffic pattern (circuit)Radio & navigationThe traffic pattern is the standard path flown around an aerodrome for take-off and landing: upwind, crosswind, downwind, base and final. Direction and altitude are published for each aerodrome.
- Transponder (Mode S)Radio & navigationA transponder replies to radar interrogations with the aircraft's code, pressure altitude and, in Mode S, its identity. It makes you visible to ATC and to other aircraft's collision-avoidance systems.
V
- VMC (visual meteorological conditions)Airspace & rulesVMC are the weather minima — visibility and distance from cloud — under which VFR flight is permitted. In Europe they are defined in SERA.5001 per airspace class.
- VOR (VHF omnidirectional range)Radio & navigationA VOR is a ground radio beacon in the 108–117.95 MHz band that lets pilots determine their bearing (radial) from the station. It remains a backup to GNSS navigation.
W
For general information only. Always use official sources, your aircraft's flight manual and current national rules for flight decisions.