What type of transponder does the suffix "/P" indicate?

The suffix "/P" indicates a transponder equipped with Mode C capability. Mode C refers to the transponder's ability to provide both identification (the aircraft's squawk code) and altitude information to air traffic control. This altitude reporting feature is crucial for maintaining safe vertical separation between aircraft, especially in busy airspace.

The transponder enhances situational awareness for air traffic controllers by allowing them to see not only the location of an aircraft but also its altitude. This function is particularly important in controlled airspace, where altitude separation is a key factor in ensuring safe operations. The use of this suffix in flight plans indicates that the aircraft has the necessary equipment to transmit altitude data, making it an essential part of the communication and surveillance system in aviation.