ATPL EASA Radio Navigation 2025 – 400 Free Practice Questions to Pass the Exam

The function of a transponder in navigation is primarily to provide automatic identification and altitude information. Transponders are essential devices embedded in aircraft that respond to interrogation signals from radar systems, such as air traffic control radar. When an aircraft's transponder receives a signal, it transmits back specific information, including a unique identifier (often referred to as a squawk code) and the aircraft's altitude. This allows air traffic controllers to track and identify the aircraft on their radar screens, significantly enhancing situational awareness and safety in busy airspace.

Transponders play a crucial role in maintaining orderly and efficient traffic management, as they enable automatic reporting of aircraft altitude and position without additional input from the pilot. This automatic identification helps minimize the risk of collision and enhances overall air traffic control capabilities.

In contrast, other functions listed in the choices do not relate to what a transponder is designed to do. Weather condition measurement is typically performed by weather radar or onboard meteorological instruments, while flight plans are filed and communicated separately, not through a transponder. Monitoring engine performance involves sensors and systems dedicated to engines rather than the transponder's primary identification function.