What is a transponder used for in aviation?

A transponder is a crucial device in aviation that plays a significant role in ensuring effective communication between aircraft and air traffic control. It transmits an aircraft's identification information, including its unique transponder code, altitude, and other relevant data. This information is sent in response to signals from ground-based radar systems, allowing air traffic controllers to track and identify aircraft within their airspace.

The primary purpose of a transponder is to enhance the safety and efficiency of air travel by improving situational awareness for both pilots and air traffic controllers. The data captured by the transponder allows for better management of airspace by providing a real-time, accurate picture of aircraft positions, which is essential for avoiding collisions and maintaining safe separation between flying aircraft.

While receiving weather information, measuring altitude, and providing navigational assistance are important functions in aviation, these tasks are typically handled by different systems or instruments, such as weather radars, altimeters, and navigational aids, respectively.