Which statement best describes the Outer Area of Class C airspace?

• A. Outer Area has a fixed radius of 10 NM
• B. Outer Area typically has a radius of 20 NM
• C. Outer Area has no defined radius
• D. Outer Area is 30 NM radius

Answer: (B)

In Class C airspace, the outer area is the ring surrounding the inner core. Its boundary is defined by a fixed radius of 10 nautical miles from the airport, forming a shelves-like layout where the outer area sits outside the 5 NM core. The bottom of the outer area is typically 1,200 feet above the airport and it extends up to 4,000 feet above the airport elevation, while the inner core goes from the surface up to 4,000 feet above the airport. So describing the outer area as having a fixed 10 NM radius best matches how Class C is arranged. The other options aren’t correct because the outer boundary isn’t 20 NM or 30 NM, and there is a defined radius. Note that entering Class C and its outer area usually requires two-way radio communication with ATC and a discrete transponder code.