Changed the meaning of TCAS shortcut to Trafic alert and terrain colision avoidance system. shortcut TCAS stands for Trafic and Colision Avoidance System, but for sum reason there, there was meening of shortcut when we ar talking about one of sides of system. there should be full meening Trafic alert and terrain Colision Avoidance System or meening only of shortcut Trafic and Colision Avoidance System.
A '''trafficTraffic alert and collisionterrain avoidanceCollision systemAvoidance System''' ('''TCAS''', pronounced {{IPAc-en|t|i:|k|æ|s}}; ''TEE-kas'') is an [[aircraft collision avoidance systems|aircraft collision avoidance system]] designed to reduce the incidence of [[mid-air collision]] (MAC) between [[aircraft]]. It monitors the [[airspace]] around an aircraft for other aircraft equipped with a corresponding active [[Transponder (aviation)|transponder]], independent of [[air traffic control]], and warns pilots of the presence of other transponder-equipped aircraft which may present a threat of MAC. It is a type of [[airborne collision avoidance system]] mandated by the [[International Civil Aviation Organization]] to be fitted to all aircraft with a maximum take-off mass (MTOM) of over {{convert|5700|kg|abbr=on}} or authorized to carry more than 19 passengers. [[Federal Aviation Regulations|CFR 14]], Ch I, part 135 requires that TCAS I be installed for aircraft with 10-30 passengers and TCAS II for aircraft with more than 30 passengers. ACAS/TCAS is based on [[secondary surveillance radar]] (SSR) [[transponder (aviation)|transponder]] signals, but operates independently of ground-based equipment to provide advice to the pilot on potentially conflicting aircraft.
[[File:Tcas EU-Flysafe.jpg|thumb|upright=1.14|Combined TCAS and [[Horizontal situation indicator|EHSI]] cockpit display (color)]]
