What is the transponder requirement for flying over Class C airspace?

When flying over Class C airspace, a Mode-C transponder is required. Class C airspace is typically found around busy airports, where there is a high volume of air traffic. The use of a transponder that broadcasts altitude information enhances situational awareness for air traffic control (ATC) and helps prevent collisions by allowing ATC to track aircraft in the vicinity.

A Mode-C transponder not only provides the aircraft's identification and location but also transmits altitude data, which is crucial for ATC in managing the flow of air traffic in these busy areas. This altitude information is important for maintaining vertical separation between aircraft navigating similarly placed altitudes.

While other types of transponders, such as Mode-S and ADS-B Out, provide additional capabilities, they are not specifically required for Class C airspace. The Mode-C requirement ensures that all aircraft entering or flying in or above Class C airspace are equipped to communicate their altitude to ATC, thereby enhancing safety and efficiency in an area where multiple aircraft are operating simultaneously.