In which class of airspace is a transponder required?

A transponder is required in Class A, B, and C airspace due to the need for enhanced surveillance and communication between aircraft and air traffic control.

Class A airspace, which extends from 18,000 feet mean sea level (MSL) up to and including flight level 600, mandates the use of a transponder because it is where the highest density of traffic operates, and air traffic control relies on transponder data to provide separation and traffic management.

In Class B airspace, which surrounds the busiest airports, a transponder is essential to identify and track aircraft entering its airspace, helping to minimize the risk of mid-air collisions due to high traffic levels.

Class C airspace, typically surrounding airports with a moderate level of commercial traffic, also requires transponders. This allows air traffic controllers to maintain situational awareness and provide separation services to the aircraft operating in and around the vicinity.

While certain Class D airspace does require a transponder under specific conditions, only the specified airspace classes of A, B, and C universally mandate transponder usage for all aircraft. Class E airspace does not require a transponder unless specified otherwise for special airspace conditions or operations.

Thus, the requirement for transponders