What is the purpose of the transponder in an aircraft?

The transponder in an aircraft serves the critical function of transmitting the aircraft's location, altitude, and identification information to air traffic control and other aircraft. This automated communication enhances situational awareness for air traffic controllers, allowing them to track the aircraft's movement while ensuring safe separation between different air traffic. By providing real-time flight data, the transponder plays a crucial role in the safety and efficiency of airspace management.

In contrast, the other options describe functions that are not primary roles of the transponder. Recording flight data is typically done by flight data recorders, weather monitoring relies on dedicated meteorological instruments, and direct communication with other aircraft usually occurs via radio communication systems rather than through the transponder. Therefore, the transponder's main purpose is to facilitate the transmission of location and altitude information, making it an essential component of modern aviation safety protocol.