Operations Dispatch Practice Exam

A control zone is airspace established specifically around an airport to provide ATC protection for aircraft during takeoff, landing, and operations in the vicinity. Because that protection is needed from the moment aircraft are at the airport area, the base of a control zone starts at the surface and extends upward to a designated ceiling. The exact top varies by airport, but the base being at ground level is what makes control zones effective for ground-level and nearby air traffic. Why the other altitudes don’t fit: 700 AGL and 2,200 AGL are floors you’ll see for other types of controlled airspace around airports (such as certain levels of Class E), but not the base of a control zone, which begins at the surface. 18,000 AGL corresponds to the base of a different class of airspace (Class A in many regions), not the base of a control zone around an aerodrome.