AN2 - Definitions

Control Zone

A controlled airspace extending upwards from the surface of the earth to a specified upper limit.

Control Area

A controlled airspace extending upwards from a specified limit above the earth. (no upper limit per definition)

Terminal Control Area

A control area normally established at the confluence of ATS routes in the vicinity of one or more major aerodromes.

A specified route designed for channeling the flow of traffic as necessary for the provision of air traffic services.

(could mean variously, airway, advisory route, controlled or uncontrolled route, arrival or departure route etc.)

Airway

A control area or portion thereof established in the form of a corridor.

(has its own controlled airspace)

The height above the ground or water of the base of the lowest layer of cloud below 20 000 ft covering more than half the sky.

The visibility forward from the cockpit of an aircraft in flight.

(ability to see and identify, only determined by the pilot)

The visibility at an aerodrome, as reported by an accredited observer.

A four-letter code group formulated in accordance with the rules prescribed by ICAO and assigned to the location of an aeronautical fixed station.

A station in aeronautical fixed service.

Aeronautical Fixed Service

A telecommunication service between specified fixed points provided primarily for the safety of air navigation and for the regular, efficient and economical operation of air traffic.

Aeronautical Fixed Communication Network

A world-wide system of aeronautical fixed circuits provided, as part of the aeronautical fixed service, for the exchange of messages and/or digital data between aeronautical fixed stations having the same or compatible communications characteristics.

An airspace to defined dimensions, above the land areas or territorial waters of a state, within which the flight of aircraft is prohibited.

An airspace of defined dimensions, above the land areas or territorial waters of a state, within which the flight of aircraft is restricted in accordance with certain specific conditions.

An airspace of defined dimensions within which activities dangerous to the flight of aircraft may exist at specific times.

A generic term relating to the vertical position of an aircraft in flight and meaning variously height, altitude or flight level.

The vertical distance of a level, a point or an object considered as a point, measured from a specified datum.

The vertical distance of a level, a point or an object considered as a point, measured from mean sea level.

The vertical distance of a point or a level, on or affixed to the surface of the earth, measured from mean sea level.

A surface of constant atmospheric pressure which is related to a specified pressure datum, 1013,2 hP, and is separated from other such surfaces by specific pressure intervals.

The altitude at or below which the vertical position of an aircraft is controlled by reference to altitudes.

The lowest flight level available for use above the transition altitude.

The airspace between then transision altitude and the transition level.

Authorisation for an aircraft to proceed under conditions specified by an air traffic control unit.

The point to which an aircraft is granted an air traffic control clearance.

Directives issued by air traffic control for the purpose of requiring a pilot to take a specific action.

A geographical location, identified by visual or other means that serves as a reference for a holding procedure.

A predetermined manoeuvre which keeps an aircraft within a specified airspace whilst awaiting further clearance.

Spacing between aircraft, levels or tracks.