The floor of Class B airspace overlying Hex airport northwest of Fort Worth Meacham Field is

The floor of Class B airspace overlying Hex airport northwest of Fort Worth Meacham Field is

• A. 2000 feet MSL
• B. 3000 feet MSL
• C. 4000 feet MSL
• D. 5000 feet MSL

Answer: (C)

In Class B airspace, each shelf has a floor that marks the lower boundary of that segment, and the floor altitude varies by location. The numbers shown on the sectional chart are in feet MSL, not AGL, and they describe where that particular shelf begins. Over Hex, which sits northwest of Fort Worth Meacham Field, the published floor for the applicable Class B shelf is 4000 feet MSL. That means the airspace starts at 4000 feet MSL in that area; below that, you’re outside the Class B, and at or above that altitude (with the proper ATC clearance and two-way comms) you’re inside the Class B. Thus the correct floor is 4000 feet MSL. The other altitudes correspond to different shelves or locations on the chart, not this particular sector.

In Class B airspace, each shelf has a floor that marks the lower boundary of that segment, and the floor altitude varies by location. The numbers shown on the sectional chart are in feet MSL, not AGL, and they describe where that particular shelf begins.

Over Hex, which sits northwest of Fort Worth Meacham Field, the published floor for the applicable Class B shelf is 4000 feet MSL. That means the airspace starts at 4000 feet MSL in that area; below that, you’re outside the Class B, and at or above that altitude (with the proper ATC clearance and two-way comms) you’re inside the Class B.

Thus the correct floor is 4000 feet MSL. The other altitudes correspond to different shelves or locations on the chart, not this particular sector.