What class of airspace requires a transponder capable of automatic pressure altitude reporting?

The requirement for a transponder capable of automatic pressure altitude reporting is specifically outlined for certain classes of airspace. Class A, B, and C airspaces all have specific regulations that mandate the use of transponders for enhanced safety, situational awareness, and traffic separation.

In Class A airspace, which starts at 18,000 feet MSL up to and including FL600, all aircraft must operate under Instrument Flight Rules (IFR) and be equipped with a Mode C transponder to report their altitude and position.

Class B airspace, which typically surrounds the busiest airports, also requires transponders to ensure that air traffic control has accurate information about the location and altitude of aircraft operating within and around this high-density traffic area.

Class C airspace, which includes a terminal area around airports with an operational control tower and a significant amount of IFR and VFR traffic, requires transponder use as well. This facilitates effective communication with air traffic control and improves safety by providing altitude information.

In contrast, Class D airspace, while requiring communication with ATC, does not necessarily require transponder equipment unless specified. Class E airspace has its own requirements based on altitude but does not uniformly impose transponder usage across all situations.

Thus,