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Class B airspace for drone pilots
Class B is the busiest airport airspace, drawn as solid blue lines on a sectional. It generally runs from the surface to 10,000 ft MSL in layered shelves, and 14 CFR 107.41 requires prior ATC authorization to fly a small drone anywhere inside it.
What is Class B airspace?
The AIM describes Class B as generally the airspace from the surface to 10,000 ft MSL around the nation's busiest airports, measured by instrument operations or passenger enplanements. Each one is custom built. It has a surface area and two or more layers, and many look like an upside-down wedding cake: the smallest circle sits on the ground at the airport, and each wider ring starts higher up. The shape is designed to contain the published instrument procedures once an aircraft enters.
For manned aircraft, an ATC clearance is required to enter regardless of weather. The study guide says the same thing for you in one line: a remote pilot must receive authorization from ATC before operating in Class B.
Sources (checked 2026-11-14): AIM 3-2: Controlled Airspace; FAA Remote Pilot sUAS Study Guide (FAA-G-8082-22).
How does Class B appear on a sectional chart?
Class B is drawn with solid blue lines. The floor and ceiling of each sector are printed in solid blue figures in hundreds of feet MSL with the last two zeros dropped. The Chart Users' Guide also notes a plus sign ahead of a floor: it means the airspace begins "from above" that altitude, and operations at or below that altitude are outside the Class B.
| What you see | What it means |
|---|---|
| 100 over SFC | Surface up to 10,000 ft MSL (the core around the airport) |
| 100 over 30 | A shelf from 3,000 ft MSL up to 10,000 ft MSL |
| 100 over 60 | The next ring out: 6,000 ft MSL up to 10,000 ft MSL |
| 100 over +50 | Begins above 5,000 ft MSL; at or below 5,000 ft MSL is outside this sector |
Those four lines show the pattern. The ceiling stays about the same while the floor steps up as you move away from the airport. Check the numbers on your own chart: the exact floors differ at every Class B, and the figures above are examples, not any specific airport.
Sources (checked 2026-11-14): FAA Aeronautical Chart Users' Guide (effective 9 July 2026); AIM 3-2: Controlled Airspace.
How do I convert a Class B floor from MSL to AGL?
Chart altitudes are MSL, but your drone's 400 ft limit in 14 CFR 107.51 is AGL. To compare them, you need the ground elevation under your flight. Get it from the chart: contour lines, spot elevations, an obstruction label such as 1037 (977) where the second number is height above ground, or a Maximum Elevation Figure for a rough upper bound. Then add your planned AGL altitude to the ground elevation to get your MSL altitude, and compare that to the floor.
Worked example
Flying below a shelf, and inside it
Say a Class B shelf is labeled 100 over 30, so its floor is 3,000 ft MSL, and your flight is under that shelf and outside the surface core.
- Ground at 400 ft MSL, flight at 300 ft AGL: 700 ft MSL. That is 2,300 ft below the floor, so you are under the shelf, not in Class B.
- Ground at 2,800 ft MSL (hilly terrain), flight at 150 ft AGL: 2,950 ft MSL. Still under the 3,000 ft floor by 50 ft.
- Same hill, flight at 300 ft AGL: 3,100 ft MSL. You are 100 ft inside the shelf and need authorization.
The numbers are made up, but the lesson holds: the same AGL altitude can be outside Class B over flat ground and inside it on a ridge.
Be conservative in practice. Spot elevations on a sectional are rounded and the ground can vary within a short distance, so if you are within a few hundred feet of a floor, use the UAS Facility Map and your LAANC app as the final check.
What does a Part 107 pilot need to fly in Class B?
14 CFR 107.41 says no person may operate a small unmanned aircraft in Class B, Class C or Class D airspace, or within the lateral boundaries of a Class E surface area designated for an airport, without prior ATC authorization. You hold a Part 107 remote pilot certificate and a registered aircraft first; the authorization comes on top of those.
Part 107 gives you two routes to the authorization. LAANC works through an FAA-approved service supplier's app and usually answers in near real time when you ask for an altitude at or below the UAS Facility Map value for that spot. If you need more than the map allows, you can send a further coordination request for up to 400 ft AGL; the FAA asks for these at least 72 hours before the flight, and you can file up to 90 days ahead. Airports that are not LAANC-enabled go through FAADroneZone instead, where the FAA says processing historically takes up to eight weeks. Unless the authorization says otherwise, you do not call the tower before you fly.
Sources (checked 2026-11-14): FAA: Part 107 Airspace Authorizations; FAA: UAS Data Exchange (LAANC).
At a busy Class B airport the UAS Facility Map grids near the runways are often low, and FAA's own page mentions grids with a 0 ft value. A 0 ft grid value means no altitude is pre-approved there. The FAA's page says Part 107 pilots may use LAANC further coordination to ask for altitude above the grid value, up to 400 ft, excluding on-airport operations.
What do the manned-aircraft Class B rules have to do with my drone?
Very little in practice, and the test knows it. Equipment and certification rules from 14 CFR 91.131, 91.215 and 91.225 (two-way radio, transponder and ADS-B Out, a private pilot certificate at certain primary airports) apply to the pilots of aircraft that carry people. The remote pilot's requirement is the single rule: prior ATC authorization under 107.41. If an answer choice says your drone needs a transponder, or that you must talk to the tower on a radio, it is describing manned operations, not Part 107.
Sources (checked 2026-11-14): AIM 3-2: Controlled Airspace; 14 CFR 107.41 (eCFR).
What is a sensible order of checks before a Class B flight?
- Find your site on the sectional and see whether it lies inside a solid blue outline. If it does not, you are outside Class B laterally and the rest of this list does not apply to Class B.
- Read the floor and ceiling for the sector. Add two zeros and treat the figures as MSL.
- Estimate the ground elevation from a spot elevation, contour or the quadrant's MEF, then add your planned altitude AGL to get altitude MSL.
- Compare. If your highest planned altitude MSL stays below the floor, you are under the shelf. If not, or if you are in the surface core, you are inside Class B.
- Open your LAANC app for the exact spot. It checks the same facts against the UAS Facility Map and returns a maximum altitude or a denial.
Doing the chart reading yourself first matters because it is what the knowledge test asks, and because it catches mistakes such as typing the wrong location into an app.
How does Class B relate to Class C, D and E?
Class B is the biggest and it overlays smaller airspace. Where a nearby Class C or Class D shelf runs up into the base of a Class B layer, the chart prints a T as the Class C ceiling: the Class C goes up to, but not including, the Class B floor above it. Class D shelves may carry a minus sign for the same kind of reason (up to, but not including). Outside the outer ring, most of the surrounding airspace is Class E from 700 ft or 1,200 ft AGL (or higher) with Class G below, which does not need authorization.
- Class C is the mid-size version with a 5 NM core and a shelf around 10 NM.
- Class D covers airports with an operating control tower and tops out around 2,500 ft above the field.
- Class E includes a surface area type that does need authorization and several types that do not.
Sources (checked 2026-11-14): FAA Aeronautical Chart Users' Guide (effective 9 July 2026); AIM 3-2: Controlled Airspace.
What are the common test traps for Class B?
- Reading the label as feet AGL. The numbers are in hundreds of feet MSL. 100 means 10,000 ft MSL, not 100 ft.
- Assuming a drone below 400 ft AGL is always outside Class B. At the surface core it is inside. Under a shelf it is outside. Only the surface-to-ceiling core touches the ground at the airport.
- Mixing up solid blue and dashed blue. Solid blue is Class B. Dashed blue is Class D.
- Thinking you can ask ATC by phone. Authorization comes through LAANC or FAADroneZone, not a call to the tower, unless the authorization says otherwise.
- Forgetting that the 400 ft rule still applies. The authorization does not raise your altitude limit; 107.51 still caps you at 400 ft AGL (or within 400 ft of a structure's top), and LAANC approvals are issued at or below 400 ft.
Practice reading the shelf labels on a real chart in the free chart lessons, and the overview in how to read airspace classes on a sectional covers the colors side by side.
Sources (checked 2026-11-14): 14 CFR 107.51 (eCFR); 14 CFR 107.41 (eCFR).
Related guides
- How to read airspace classes on a sectional chart
- Class C airspace for drone pilots
- Class D airspace for drone pilots
- Free sectional chart practice
- Part 107 Airspace and Sectional Chart Practice Questions
- All Part 107 guides
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Sources
- AIM 3-2: Controlled Airspace, checked 2026-11-14
- FAA Aeronautical Chart Users' Guide (effective 9 July 2026), checked 2026-11-14
- FAA Remote Pilot sUAS Study Guide (FAA-G-8082-22), checked 2026-11-14
- 14 CFR 107.41 (eCFR), checked 2026-11-14
- 14 CFR 107.51 (eCFR), checked 2026-11-14
- FAA: Part 107 Airspace Authorizations, checked 2026-11-14
- FAA: UAS Data Exchange (LAANC), checked 2026-11-14
How this page was made: written by Certloom Learning from the sources above, with the rules checked against the current regulation text. Practice items are original questions from the app's reviewed bank. Spot an error? certloomlearning@gmail.com.