Which airspace around busy airports requires two-way radio communications with ATC prior to entry?

• A. Class A
• B. Class B
• C. Class E
• D. Class C

Answer: (D)

Two-way radio contact with ATC before entering certain controlled airspace is required to help ATC manage traffic and separate aircraft safely around busy areas.

This question points to Class C airspace, which circles many busy airports. Before you enter, you must establish two-way radio communication with ATC on the proper frequency. ATC will usually assign you a discrete transponder code (and you’ll typically need to have altitude reporting as well). You must stay in two-way contact while inside Class C.

For context, Class B airspace also requires contact and a definite clearance to enter, and Class A is IFR only (you don’t operate VFR there). Class E, on the other hand, does not require entering aircraft to establish two-way communications with ATC. The requirement to establish two-way communication before entry is a hallmark of Class C around busy airports.