Airborne collision avoidance system

Avionics system to avoid aircraft collision

An airborne collision avoidance system (ACAS; usually AY-kas) operates independently of ground-based equipment and air traffic control in warning pilots of the presence of other aircraft that may present a threat of collision. If the risk of collision is imminent, the system recommends a maneuver that will reduce the risk of collision. ACAS standards and recommended practices are mainly defined in Annex 10, Volume IV, of the Convention on International Civil Aviation.

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