The Blue Shelves Around Major Hubs
Recognize Class B boundaries and read each floor and ceiling before deciding whether a planned altitude enters the airspace.
YOU WILL BE ABLE TO
- 01Identify the rule, source, or principle behind this idea: Class B is depicted with solid blue boundaries and individually tailored shelves around high-traffic airports.
- 02Explain the operational effect of this idea: Charted floor and ceiling fractions are in hundreds of feet MSL.
- 03Apply the lesson to a new mission and defend a go, modify, or no-go decision.
01 / MISSION
Begin with the operating problem.
A rooftop shoot sits under a shelf labeled 100/40, with the roof at 3,700 feet MSL.
02 / CORE BRIEF
What the remote pilot needs to know.
Class B is depicted with solid blue boundaries and individually tailored shelves around high-traffic airports.
Charted floor and ceiling fractions are in hundreds of feet MSL.
Part 107 operation inside Class B requires prior FAA authorization.
03 / PILOT DECISION
Make the call.
Convert the proposed AGL altitude to MSL and compare it with the 4,000-foot shelf floor before deciding whether the flight enters Class B.
04 / FIELD CHECK
Put it into the flight plan.
Write terrain or launch elevation, planned AGL, resulting MSL, and shelf limits on the map.
05 / KNOWLEDGE CHECK
What does 100/40 mean on a Class B shelf?
Reveal the debrief
A ceiling of 10,000 feet MSL and a floor of 4,000 feet MSL.
RELATED FAA REFERENCES
Verify before you fly.
- FAA — Aeronautical Chart User's Guide
- 14 CFR Part 107 — current eCFR
- FAA — Part 107 Airspace Authorizations
Educational summary only. Current regulation, FAA approval conditions, manufacturer instructions, and site-specific facts control the operation.