ICAO terminology

(ICAO Annex Terminology)

A glossary chapter, but the exam mines it for precise definitions. The ones that recur:

• Altitude: vertical distance above mean sea level.
• Height: vertical distance above a specified datum (e.g. aerodrome).
• Elevation: vertical distance of a point on the surface above MSL.
• Flight level: a constant-pressure surface referenced to 1013.2 hPa.
• Manoeuvring area: the part of an aerodrome used for take-off, landing and taxiing, excluding aprons.
• Movement area: the manoeuvring area plus the apron(s).
• Apron: the area for parking, loading/unloading, refuelling and maintenance.
• Cloud ceiling: the height of the lowest cloud layer below 20,000 ft covering more than half the sky.
• VMC / IMC: meteorological conditions at or above / below the specified visibility, distance-from-cloud and ceiling minima.
• Control Zone: controlled airspace from the surface to a specified upper limit.
• Control Area: controlled airspace from a specified height upward.
• Flight visibility / ground visibility: visibility forward from the cockpit / as reported by an observer at the aerodrome.