What is TCAS?

TCAS (Traffic Collision Avoidance System) is an airborne system designed to reduce the incidence of mid-air collisions between aircraft. It operates independently of ground-based air traffic control and alerts pilots to potential conflicts, providing guidance on avoiding action. It uses transponder signals from nearby aircraft to determine their altitude, range, and bearing and can issue a 'Traffic Advisory' (TA) to alert the pilot of nearby traffic or a 'Resolution Advisory' (RA) which advises the pilot on how to adjust their flight path to avoid a collision.