🔍 Key Concepts

• Difference between Mode C and Mode S transponders • Purpose of secondary surveillance radar (SSR) and airborne safety systems • What systems are used specifically for collision avoidance in controlled airspace

💭 Think About

• Which answer choices describe a function that an aircraft could realistically perform with a data-link type transponder enhancement beyond simple altitude reporting? • Which options sound like they would require completely separate dedicated equipment (for example, weather detection or voice radios), not just a smarter transponder? • Think about what critical safety function in busy airspace benefits from aircraft broadcasting more detailed identity and altitude information to each other and to ATC.

✅ Before You Answer

• Eliminate any options that would require primary radar (ground-based, non-cooperative) rather than a cooperative transponder reply system. • Ask whether lightning detection or VHF voice backup normally comes from separate avionics, not the transponder itself. • Focus on which option most directly uses improved aircraft-to-aircraft and aircraft-to-ground data exchange to enhance safety in dense traffic.