What feature does Mode S introduce that enhances surveillance compared to older transponder modes?

What feature does Mode S introduce that enhances surveillance compared to older transponder modes?

• A. It stores electronic flight bag data.
• B. It provides selective addressing and enhanced data reporting for surveillance.
• C. It automatically lands the aircraft.
• D. It uses analog voice channels.

Answer: (B)

Mode S changes how transponders respond to air traffic surveillance by adding selective addressing and enhanced data reporting. Each aircraft has a unique address, so ground radar can interrogate a specific airplane and receive a reply only from that aircraft. This reduces radar clutter and makes tracking more precise. In addition, Mode S expands the data that can be reported, providing flight identification (such as a callsign) and more surveillance data (like altitude and other status information), giving controllers a clearer picture of who is where. These improvements over older A/C modes—which didn’t support selective addressing or richer downlink data—directly enhance surveillance efficiency and reliability.

Mode S changes how transponders respond to air traffic surveillance by adding selective addressing and enhanced data reporting. Each aircraft has a unique address, so ground radar can interrogate a specific airplane and receive a reply only from that aircraft. This reduces radar clutter and makes tracking more precise. In addition, Mode S expands the data that can be reported, providing flight identification (such as a callsign) and more surveillance data (like altitude and other status information), giving controllers a clearer picture of who is where. These improvements over older A/C modes—which didn’t support selective addressing or richer downlink data—directly enhance surveillance efficiency and reliability.