Class B airspace

Class B airspace is controlled airspace established around certain high-volume airports. It is commonly shaped like an inverted wedding cake, with shelves at different altitudes and lateral boundaries. A pilot operating under VFR generally needs an explicit ATC clearance before entering Class B airspace.

What it governs

The exact dimensions, floors, ceilings, operating hours, and communication requirements are published on the current chart and in related airport information. Class B boundaries can extend well beyond the airport, and the shelves may have different floors. A pilot must identify the correct sector and understand the route through the airspace before requesting entry.

Two-way communication and a clearance are distinct concepts. Establishing communication with ATC does not by itself authorize entry into Class B. The controller must issue the applicable clearance, and the pilot must comply with it or advise ATC when unable.

Example

A VFR aircraft approaches a Class B shelf with a floor of 3,000 ft MSL. The pilot remains clear until receiving an explicit clearance, even if the aircraft is communicating with a controller. A route below the shelf may still require attention to terrain, other airspace, and traffic.

Why it matters

Class B airspace can change the route, altitude, communication frequency, and workload for a VFR flight. The chart depiction is not enough by itself. Pilots should review the chart, frequencies, chart notes, and current notices before departure.

Use the current FAA chart and Aeronautical Information Manual for the governing requirements. The airspace shown on a general reference page may not reflect a later chart change.

Related terms and tools

• Class C airspace
• Visual flight rules
• FAA airspace resources