Definition.

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

Source: ICAO Annex 2: Rules of the Air

Description

The prohibited area is airspace that is completely forbidded to aircraft. It constitutes the most stringent form of airspace restriction. Therefore, it has become normal practice to establish such areas only to protect important installations and critical industrial complexes whose damage as a result of an aircraft accident could have catastrophic consequences (e.g. nuclear power plants or chemical plants) or especially sensitive installations which are essential for the national security. In other words, prohibited areas are established in order to protect a ground installation from aircraft (as opposed to danger areas, where the goal is to protect aircraft from dangerous activities).

The vertical and lateral dimensions of prohibited areas are publicised in national Aeronautical Information Publications (AIPs) together with the hours of operation where applicable. It should be noted that prohibited areas can only be established over sovereign territory (i.e. the land area of a State and its territorial waters) and not over high seas (where only danger areas can be established).