What is the primary purpose of a Transponder in IFR flights?

The primary purpose of a transponder in IFR flights is to provide altitude data to air traffic control. Transponders play a critical role in improving air traffic safety and efficiency. When an aircraft is equipped with an operational transponder, it automatically sends a signal that includes the aircraft's identifying information along with its altitude, which is derived from the aircraft's altimeter. This information is then received by air traffic control radar systems, enabling controllers to track the aircraft's location and altitude accurately.

This capability enhances situational awareness for both air traffic controllers and pilots, as it allows for better separation of aircraft and serves as a vital tool for ensuring safety in congested airspace. The signals transmitted by the transponder also help improve radar displays, making it easier for controllers to manage various flight operations.

While the other choices may incorporate aspects of aviation technology, they do not specifically define the fundamental function of a transponder within the context of IFR operations as precisely as the correct answer does.