Aviation Glossary

A METAR is a standardized international aviation routine weather report describing observed surface conditions at an aerodrome at a specific time.

A TAF is an official airport terminal weather forecast established for a 5-statute-mile radius over a 24 to 30-hour period.

An ILS is a standard precision instrument approach system providing lateral runway centerline guidance (Localizer) and vertical glide path guidance (Glide Slope).

A VOR is a ground-based radio navigation transmitter that radiates 360 magnetic radials outward for aircraft course tracking and position fixing.

RNAV is a flight navigation method allowing direct point-to-point routing between geographic waypoints without the need to overfly ground-based navigation aids.

RNP is a Performance-Based Navigation (PBN) specification requiring onboard performance monitoring and alerting (OPMA) to guarantee containment accuracy.

A SID is a published IFR departure route linking the takeoff runway end to enroute airway structures with obstacle clearance climb gradients.

A STAR is a published IFR arrival procedure channeling aircraft from cruising airways down to initial approach fixes (IAF) in terminal airspace.

QNH is the barometric altimeter setting that calibrates the instrument to display true altitude above Mean Sea Level (MSL).

QFE is the barometric altimeter setting that zeroes the instrument on the runway surface, displaying height above airport level (AGL).

QNE refers to standard pressure altitude indicated when the barometric subscale is set to the standard datum of 29.92 inHg / 1013.2 hPa.

Top of Descent (TOD) is the computed geographic point along a flight route where an aircraft must begin descending from cruise altitude to reach the target fix on a 3-degree descent profile.

DME is a radio navigation transponder that measures the slant-range distance in nautical miles between an aircraft and a ground beacon.

VFR are Visual Flight Rules under which an aircraft is flown with continuous visual reference to the ground and natural horizon in Visual Meteorological Conditions (VMC).

IFR are Instrument Flight Rules allowing aircraft operations in Instrument Meteorological Conditions (IMC) solely with cockpit instruments under ATC separation.

A NOTAM is an official telecommunication notice containing vital information concerning the establishment, condition, or change in any aeronautical facility, service, or hazard.