What is a 'transponder' in aviation?

A transponder in aviation is an electronic device located on an aircraft that serves a crucial role in communication and identification. It operates by receiving signals from ground radar systems and responding with specific information, such as the aircraft's altitude and identification code. This capability is essential for air traffic control to monitor the aircraft's position and altitude in real-time, thereby improving safety and situational awareness in increasingly congested airspace.

The transponder enhances the effectiveness of radar systems, allowing air traffic controllers to precisely track and manage multiple aircraft within their jurisdiction. While it is involved in transmitting flight information, the core function that distinguishes a transponder is its ability to respond to radar interrogations with vital data that contributes to air traffic management.