If you are flying at 2,500 feet MSL near Addison Airport, are you in Class B airspace?

• A. No, the floor is 3,000 feet MSL
• B. Yes, you are in Class B
• C. Only if cleared by ATC
• D. Only during daylight hours

Answer: (A)

The key idea is that Class B airspace has specific base levels (floors) that can vary by location. Being in Class B depends on both being inside the defined lateral boundaries and being at or above the floor. For Addison, the Class B shelf in that area begins at 3,000 feet MSL. So at 2,500 feet MSL you are below the floor, meaning you are not within Class B at all. You would be in Class E (or G near the surface) instead, depending on exact position. The need for ATC clearance only applies if you are operating within Class B, which isn’t the case here. Daylight hours don’t affect Class B airspace boundaries or requirements either.