Which airspace is typically depicted as a three-tiered 'wedding cake' around busy airports and requires explicit clearance to enter, with a two-way radio and Mode C transponder?

Which airspace is typically depicted as a three-tiered 'wedding cake' around busy airports and requires explicit clearance to enter, with a two-way radio and Mode C transponder?

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

Answer: (A)

Class B airspace is shown as a three-tiered “wedding cake” around busy airports, with stacked shelves that extend upward from the surface in concentric layers. To operate there, you must have explicit ATC clearance before entering and you must stay in two‑way radio communication with ATC while inside. A Mode C transponder is required so ATC can see your altitude, which helps manage traffic in these busy areas. This combination—clearance to enter, continuous two-way communication, and altitude reporting via Mode C—is what makes Class B the most restrictive and the cake-like depiction a telltale sign. Other airspaces around busy hubs may have layered structures or require radio contact and a Mode C transponder (like Class C), but they’re not depicted with three stacked tiers in the same way. Class D surrounds a towered airport with radio communication requirements but generally does not require a Mode C transponder, and Class E is controlled airspace that typically doesn’t require explicit entry clearance for VFR, and it isn’t the classic “wedding cake” shape.

Class B airspace is shown as a three-tiered “wedding cake” around busy airports, with stacked shelves that extend upward from the surface in concentric layers. To operate there, you must have explicit ATC clearance before entering and you must stay in two‑way radio communication with ATC while inside. A Mode C transponder is required so ATC can see your altitude, which helps manage traffic in these busy areas.

This combination—clearance to enter, continuous two-way communication, and altitude reporting via Mode C—is what makes Class B the most restrictive and the cake-like depiction a telltale sign. Other airspaces around busy hubs may have layered structures or require radio contact and a Mode C transponder (like Class C), but they’re not depicted with three stacked tiers in the same way. Class D surrounds a towered airport with radio communication requirements but generally does not require a Mode C transponder, and Class E is controlled airspace that typically doesn’t require explicit entry clearance for VFR, and it isn’t the classic “wedding cake” shape.