2.2 Class B Airspace

Class B Airspace

Class B ("Bravo") airspace surrounds the nation's busiest airports — high-volume hubs with heavy airline and instrument flight rules (IFR) traffic such as Atlanta (ATL), Los Angeles (LAX), Chicago O'Hare (ORD), and Dallas/Fort Worth (DFW). It is the most tightly controlled airspace a Part 107 pilot will realistically encounter, and it is the airspace most likely to deny or sharply limit a drone authorization.

Dimensions and the Wedding-Cake Shape

Class B is built as an inverted (upside-down) wedding cake of stacked shelves:

• Surface core: from the surface up to roughly 7,000-10,000 ft MSL, extending about 5-10 nautical miles (NM) from the primary airport.
• Middle shelves: each progressively wider, with a defined floor and ceiling.
• Outer shelf: the widest layer, often reaching 20-30 NM out, with a floor that may begin several thousand feet above the ground.

Because the floors rise with distance, a drone flying at 380 ft AGL several miles out may sit beneath a Class B shelf (in Class G) rather than inside it. Always confirm with the chart and the facility map.

Reading Class B on a Sectional

Class B is drawn with solid blue lines in concentric shapes around the airport. Each shelf carries an altitude fraction:

• Top number = ceiling, bottom number = floor, both in hundreds of feet MSL.
• 100/30 = ceiling 10,000 ft MSL over a floor of 3,000 ft MSL.
• SFC in place of the floor means the shelf reaches the surface.

Part 107 Operations in Class B

To fly inside Class B you must:

1. Obtain prior ATC authorization through LAANC (near-real-time) or a manual DroneZone request.
2. Stay within every condition the authorization specifies (area, altitude, time window).
3. Maintain visual line of sight and traffic awareness; remember manned aircraft on approach descend through low altitudes here.
4. Follow all standard Part 107 limits — the authorization does not waive the 400 ft AGL ceiling or VLOS.

LAANC reality check: even where LAANC is available, the auto-approvable altitude in the Class B surface core is frequently 0 ft AGL, meaning no automatic approval. You then submit a manual DroneZone request and may wait days or weeks.

UAS Facility Maps (UASFM)

The FAA publishes UAS Facility Maps for Class B, C, D, and Class E surface airports. Each map divides the area into grid cells, and each cell carries the maximum altitude LAANC can auto-approve:

• Values range from 0 to 400 ft AGL.
• A 0 cell means no LAANC approval is possible there; use the manual process.
• Cells nearest the runways trend low (0-50 ft); cells far from the flight paths may show the full 400 ft.

Manned-Aircraft VFR Rules (Context Only)

The Mode C Veil

The Mode C Veil is a 30-NM ring around the Class B primary airport in which manned aircraft must carry an altitude-reporting (Mode C) transponder. This does not apply to small UAS under Part 107 — your drone needs no transponder. Exam writers may try to make you require one; the answer is that the drone needs authorization, not a transponder.

Common Traps

• Confusing the floor with the ceiling: the bottom number is the floor.
• Assuming a city under Class B is entirely off-limits — outer shelves with high floors leave Class G below them.
• Believing a transponder or radio is required for the drone; it is not.

Why Class B Is the Hardest Airspace for Drones

Class B exists to protect the heaviest concentration of airline traffic in the country, so the FAA designs the UAS Facility Maps conservatively. In the surface core, where airliners land and depart, the maps frequently publish a ceiling of 0 ft AGL, meaning automation simply will not approve a flight there. This is not a chart-reading nuance — it is a hard operational reality that surprises many new pilots who assume a remote pilot certificate grants access everywhere.

The practical takeaway is to expect denials near the runways and to plan commercial work in the outer shelves or just outside the Class B boundary, where Class G beneath a high shelf floor is common.

Reading a Class B Excerpt Methodically

When the test supplement shows a Class B excerpt, work the problem in a fixed order. Find the solid blue boundary nearest your marked location, read its fraction label, and convert both numbers to MSL by multiplying by 100. Then ask whether the floor reaches the surface (SFC) at your point: if it does, you are inside Class B and need authorization; if the floor sits thousands of feet up, you are in the Class G beneath it. Finally, cross-check against any obstruction or terrain near your point, because Class B sites are often urban with tall buildings and antenna farms that compress your usable altitude band even further.

Worked Scenario

A drone job sits beneath a Class B shelf labeled 100/40 about 12 NM from the primary airport. The floor is 4,000 ft MSL and the ground is near 200 ft MSL, so a drone at 400 ft AGL (roughly 600 ft MSL) is 3,400 ft below the shelf floor — squarely in Class G, requiring no authorization. Move the same job into a surface-core shelf labeled 100/SFC, and the airspace reaches the ground; now LAANC or a manual DroneZone authorization is mandatory, and the UASFM ceiling there may be 0 ft. Identifying which shelf you are under is the entire exercise the exam tests.