Learning Objectives

At the end of this lesson, you will be able to:

• Describe the general shape and characteristics of Class B airspace.
• Find Class B airspace on a sectional chart.
• Determine the boundaries, including the floor and ceiling of each ring, of Class B airspace.

Class B Airspace: “B” for Busy

Class B airspace is reserved for the nation’s busiest airports—major hubs with extensive commercial traffic such as New York (JFK), Minneapolis (MSP), Houston (IAH), and Atlanta (ATL). It is designed to protect the aircraft arriving and departing these airports, providing a controlled environment that helps prevent conflicts with other air traffic. While smaller general aviation aircraft may be allowed into Class B if permitted by air traffic control, drone pilots should generally avoid this airspace without prior authorization.

The Upside-Down Wedding Cake Shape:

When visualized in three dimensions, Class B airspace resembles an inverted wedding cake. Closest to the airport, the Class B airspace starts at the surface and extends upward. As you move farther from the airport, the airspace “steps” outward and upward in layers. Each successive layer begins at a higher altitude than the one inside it.

This tiered structure ensures that commercial and high-speed traffic remain in carefully controlled corridors during climb-out after takeoff and descent before landing.

Class B airspace is shaped like an upside-down wedding cake.

Identifying Class B Airspace on Sectional Charts:

On VFR sectional charts, Class B airspace is shown as a series of concentric solid blue lines around the primary airport. Each “ring” corresponds to a different layer of the upside-down wedding cake. The chart will display two numbers for each section, representing the floor and ceiling of that Class B segment:

• Floor: The lower altitude at which Class B airspace begins in that segment.
• Ceiling: The upper altitude limit of Class B airspace.

In this example, the floor of the Class B airspace is 7,000 feet MSL and its ceiling is 10,000 feet MSL.

These altitudes are given in hundreds of feet MSL (Mean Sea Level). For example, “70” indicates 7,000 feet MSL, and “100” indicates 10,000 feet MSL. The top number in the pair is always the ceiling, and the bottom number is the floor. If the floor is listed as “SFC,” it means the Class B airspace starts at the surface.

Class B airspace is depicted as concentric rings of solid blue lines around the major airport.

Variations Around the Airport:

Not every “ring” or “slice” of Class B airspace has uniform altitude limits throughout its entire circumference. The sectional chart often includes dividing lines and slightly different sets of altitude numbers for different sections around the airport. These variations accommodate differing traffic patterns or terrain features.

In other words, one side of the Class B ring might start at 3,000 feet MSL, while a neighboring section—separated by a boundary line—could start at 4,000 or 6,000 feet MSL. Always pay attention to these dividing lines and the corresponding numbers to understand exactly where each segment of Class B airspace is defined.

Key Takeaways for Drone Pilots:

• Class B airspace is associated with major airports and is heavily controlled.
• It resembles an inverted wedding cake, with multiple layers “stepping” up and out as you move away from the airport.
• Always check the sectional chart carefully to determine the correct altitude limits for each portion of Class B.
• Drone pilots must have prior authorization from ATC to operate within Class B airspace.