What is the function of a transponder?

The function of a transponder is primarily to transmit the aircraft's position and altitude to air traffic control. When activated, it sends out a signal that includes information about the aircraft's location and altitude, allowing air traffic controllers to monitor and manage air traffic effectively. This capability is crucial for maintaining situational awareness and ensuring safety in crowded airspace, as it helps to prevent collisions between aircraft.

Furthermore, transponders can also respond to radar interrogations from ground control and provide necessary information regarding the aircraft’s identification and its current operational status, enhancing the safety net around the aircraft. While other answers may refer to various communication functions or tracking mechanisms, they do not accurately capture the core purpose of a transponder in air traffic management.