Which suffix indicates an aircraft equipped with a transponder featuring Mode C but no DME?

The suffix indicating an aircraft equipped with a transponder featuring Mode C but lacking DME is indeed represented by the letter "U." This designation is part of the Standardized Reporting Criteria used in aviation to convey critical information about an aircraft's equipment capabilities.

Mode C transponders transmit aircraft altitude information, which is essential for air traffic control to manage separation between aircraft effectively and ensure safe operations in controlled airspace. The letter "U" specifically shows that the aircraft has the capability for Mode C surveillance, indicating it can transmit altitude data, but does not have Distance Measuring Equipment (DME) onboard.

Understanding these suffixes helps air traffic controllers quickly assess the capabilities of various aircraft, ensuring safe and efficient airspace management.