What does "TCAS" do in an aircraft?

TCAS, or Traffic Alert and Collision Avoidance System, is a crucial safety feature used in aircraft. Its primary function is to monitor air traffic in the vicinity of the aircraft and provide alerts to prevent potential mid-air collisions. TCAS operates by interrogating nearby transponder-equipped aircraft for their altitude, position, and vector information, which allows it to assess the risk of collision with other aircraft. When a potential conflict is detected, TCAS issues a resolution advisory to the pilots, recommending maneuvers such as climbing or descending to maintain safe separation from other aircraft. This active collision avoidance capability significantly enhances the overall safety of air travel by providing pilots with timely and actionable information to avoid dangerous encounters.

The other options, while relevant to different systems and functions within aviation, do not pertain to the specific role of TCAS. Monitoring weather conditions, tracking flight paths, and regulating cabin pressure are functions managed by other systems or technologies within the aircraft, which are separate from the collision avoidance responsibilities of TCAS.