What must a pilot do to operate in Class A airspace?

To operate in Class A airspace, a pilot must obtain clearance both day and night. Class A airspace is typically found at altitudes above 18,000 feet up to and including flight level 600. This airspace is designated for instrument flight rules (IFR) operations only, meaning that all aircraft must be operating under IFR and must receive explicit clearance from Air Traffic Control (ATC) before entering.

This requirement ensures that the significant amount of traffic in Class A airspace is controlled and safely managed, reducing the risk of mid-air collisions. It is essential for pilots to maintain communication with ATC and to follow all clearance instructions to operate safely in this airspace.

In contrast, the other options would not be sufficient for safely operating in Class A airspace. Notifying the tower prior to entering does not encompass the necessary clearance required for IFR operations, while flying under visual flight rules is not permitted in this airspace. Additionally, the statement that no special requirements apply is inaccurate because Class A has specific regulations that all pilots must adhere to.