How is Class E airspace best described in terms of control and base altitudes?

• A. Uncontrolled airspace with no ATC services
• B. Controlled airspace with a fixed base altitude
• C. Controlled airspace with varying bases
• D. Airspace requiring ATC clearance to enter

Answer: (C)

Class E is controlled airspace, but its floor is not fixed everywhere. The base altitude where Class E begins varies by location and purpose. In many areas the floor is 1,200 feet above ground level (AGL), but in others it starts at 700 feet AGL, and in some places it begins right at the surface to support instrument procedures around certain airports. This variability is what makes Class E “controlled airspace with varying bases.”

As for how this affects entry: VFR pilots can enter Class E without ATC clearance, while IFR traffic is under ATC control and requires the appropriate clearance and separation services. The fixed-base description or the notion that entry requires ATC clearance for all operations aren’t accurate for Class E.