What is the definition of a Mode S transponder?

• A. A transponder for ground communication
• B. A radar system for ATC
• C. The airborne ATC transponder referred to in CAN-TSO-C112
• D. A transponder system for VFR flights only

Answer: (C)

The definition of a Mode S transponder is indeed related to its role as an airborne ATC transponder, specifically detailed in the Canadian Technical Standard Order (CAN-TSO-C112). Mode S transponders are designed to provide aircraft identification and altitude information to air traffic control. They operate using selective addressing, which allows for communication with ground-based radar systems without interference from other aircraft, thereby enhancing airspace safety and efficiency.

The importance of the Mode S transponder lies in its ability to transmit data not just to radar, but also to cooperate with Automatic Dependent Surveillance-Broadcast (ADS-B) systems. This means that it can provide both passive and active surveillance capabilities, helping improve situational awareness for air traffic management.

Understanding this technology is vital for aviation professionals because it forms a crucial part of modern air traffic control and operations, increasing safety by ensuring accurate tracking and communication of aircraft during flight.