What is required for aircraft operating in Class E airspace above 10,000 feet MSL?

For aircraft operating in Class E airspace above 10,000 feet MSL, a transponder is required. This requirement is established by the FAA regulations to enhance safety and situational awareness. The transponder, particularly with Mode C capability, provides altitude information to air traffic control, which assists in tracking aircraft in crowded airspace. This enhances the overall safety of the flight environment, especially when operating near busy terminals or in areas with a high volume of traffic.

Furthermore, while two-way radio communication is a requirement in some other airspaces, it is not a universal requirement for Class E airspace unless you are operating under specific conditions or near controlled airspace. Visual observers or flight plan filing are not mandatory for operating in Class E above 10,000 feet, thus reinforcing the necessity of equipping aircraft with a transponder.