Who is responsible for maintaining separation when an aircraft is responding to a TCAS alert?

The responsibility for maintaining separation when an aircraft is responding to a Traffic Collision Avoidance System (TCAS) alert falls to the flight crew. This system is designed to enhance flight safety by providing information and resolution advisories to the pilots when a potential collision with another aircraft is detected.

When TCAS generates an alert, the pilots are trained to take immediate action to either climb or descend according to the instructions provided by the TCAS. It is crucial during such scenarios for the flight crew to prioritize the TCAS advisories to ensure vertical separation from potentially conflicting aircraft.

While Air Traffic Control (ATC) has a pivotal role in managing air traffic and providing instructions under normal operations, once a TCAS alert is triggered, the flight crew assumes the responsibility to respond without needing to communicate with ATC. This ensures rapid and decisive action to prevent mid-air collisions, as the flight crew has the immediate situational awareness required to execute the necessary maneuvers.

In support of this, ATC will typically be aware of the situation and may assist or provide further instructions after the flight crew has responded to the TCAS alert, ensuring a coordinated response once the immediate threat is mitigated.