What does Class A airspace require for entry?

• A. No clearance needed to enter Class A.
• B. An explicit ATC clearance to enter, and operations are generally IFR only.
• C. Two-way radio contact is sufficient.
• D. Special ground permission is required.

Answer: (B)

Entering Class A airspace requires an explicit ATC clearance before you enter, and operations there are generally IFR only. This airspace is fully controlled and in the U.S. it starts at 18,000 feet MSL and goes up to FL600. VFR operations aren’t permitted there, so pilots must be on an IFR flight plan and receive a clearance to enter, while maintaining two-way radio contact with ATC and following their instructions. The other options don’t fit because entry isn’t allowed without clearance, and simply having two-way radio contact isn’t enough without ATC authorization; there’s no separate ground permission granting access.