Practical info: TCAS, the airliner collision avoidance system

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THE TCAS (Traffic Collision Avoidance System) is a essential safety system boarded in modern airliners for prevent mid-air collisions. It works by detecting other aircraft in the vicinity and providing alerts and maneuver instructions to pilots for avoid dangerous situations.

TCAS relies on the transponders on board each aircraft. These transponders send out radar signals containing information such as the aircraft’s altitude and position. When an aircraft is equipped with TCAS, it can establish communication between the TCAS systems of two aircraft in flight close to each other.

When two TCAS-equipped aircraft approach at a potentially dangerous distance, the systems activate. TCAS analyzes transponder data and determines each aircraft’s planned path. If a risk of collision is identified, the system automatically generates audio and visual alerts in the cockpit to alert pilots to the situation.

TCAS has two main alert levels :
-Traffic Advisory (TA) – Traffic Alert: When TCAS detects another aircraft nearby, it issues a TA alert to warn pilots of the presence of potential traffic. At this point, the system also provides information about the position and altitude of the detected aircraft.
-Resolution Advisory (RA) – Resolution Advisory: If the TCAS considers that the aircraft are at risk of approaching dangerously, it generates an RA alert. This alert is more urgent and includes maneuver instructions to avoid the collision. Pilots are required to follow these instructions to ensure separation between aircraft.

TCAS is a vital tool for aviation safety, as it allows pilots to react quickly and in a coordinated manner in the event of a risk of collision. It is independent of air traffic control and can therefore take immediate action even in the absence of radar or radio communications. Remember that it was a faulty TCAS that led to two crashes of the Boeing 737-MAX.

John Walker Avatar