What information does Mode C provide in SSR?

What information does Mode C provide in SSR?

• A. Altitude information via the transponder
• B. Identity code
• C. Ground speed
• D. Weather data

Answer: (A)

Mode C is the altitude reporting part of the SSR transponder. The transponder encodes the aircraft’s barometric altitude and returns it in the SSR reply, giving the altitude in 100-foot increments referenced to standard pressure (1013 hPa). This allows ATC to know each aircraft’s vertical position and maintain vertical separation without relying on voice reports. The identity code comes from Mode A, not Mode C; ground speed and weather data aren’t provided by Mode C.

Mode C is the altitude reporting part of the SSR transponder. The transponder encodes the aircraft’s barometric altitude and returns it in the SSR reply, giving the altitude in 100-foot increments referenced to standard pressure (1013 hPa). This allows ATC to know each aircraft’s vertical position and maintain vertical separation without relying on voice reports. The identity code comes from Mode A, not Mode C; ground speed and weather data aren’t provided by Mode C.