What does the suffix 'B' signify regarding an aircraft's transponder and DME capabilities?

The suffix 'B' indicates that the aircraft is equipped with a transponder that does not have Mode C capabilities, but it is capable of Distance Measuring Equipment (DME). This is significant because it helps air traffic controllers understand what types of equipment an aircraft is using, which in turn influences how they manage air traffic and maintain safety.

In straightforward terms, the absence of Mode C means that while the transponder can provide identification and basic indications of altitude, it lacks the altitude-reporting capability that Mode C provides. However, the DME capability allows the aircraft to determine its distance from DME ground stations, which is important for navigation and approach procedures.

Understanding these capabilities is essential for efficient communication between pilots and air traffic control, enabling more effective flight routing and management of airspace. Being aware of an aircraft's transponder and navigation capability streamlines operations and maintains safety in controlled airspace.