TCASjärjestelmä

TCASjärjestelmä, an acronym for Traffic Alert and Collision Avoidance System, is an airborne radar system designed to prevent mid-air collisions. It works by interrogating the transponders of other aircraft in the vicinity, which are required to be fitted to all commercial airliners and most other aircraft. The TCAS unit in an aircraft receives signals from these transponders and uses them to calculate the bearing, altitude, and relative speed of other equipped aircraft.

When a potential conflict is detected, TCAS issues advisories to the pilots. These advisories can be "traffic advisories" (TAs), which alert pilots to the presence of other aircraft, or "resolution advisories" (RAs), which provide specific instructions for evasive maneuvers to avoid a collision. RAs are designed to be coordinated between aircraft, meaning if one aircraft is instructed to climb, the other will be instructed to descend.

The system operates in several modes, including standby, transmit only, and active. In active mode, it continuously monitors for other aircraft and issues advisories as needed. TCAS is a crucial safety system in modern aviation, significantly reducing the risk of catastrophic mid-air collisions. It complements air traffic control by providing an independent layer of protection within the aircraft itself.