What is the purpose of a mode C transponder in controlled airspace?

The mode C transponder serves a crucial function in controlled airspace by transmitting information about an aircraft’s altitude and identification to air traffic control (ATC). This information enhances situational awareness for ATC and aids in the effective management of air traffic.

When an aircraft is equipped with a mode C transponder, it continuously broadcasts its altitude along with its transponder code, which uniquely identifies the aircraft. This allows ATC to monitor the position and altitude of the aircraft on radar displays, facilitating safe separation from other aircraft and efficient navigation through controlled airspace.

While communication with air traffic control is essential for safety and navigation, the primary function of a mode C transponder is not simply to communicate but to provide specific data regarding altitude and identification. Similarly, receiving ATIS updates and sending distress signals are important capabilities in aviation, but they do not pertain directly to the specific function of a mode C transponder within controlled airspace.