What are the dimensions of Class D airspace?

Class D airspace is designed to manage the operation of aircraft in the vicinity of airports that have a control tower, ensuring safe and efficient flight operations. The standard dimensions for Class D airspace typically consist of a radius of 4 nautical miles from the center of the airport, extending vertically from the surface up to an altitude of 2,500 feet above ground level (AGL).

The reason that a radius of 4 nautical miles and extending to 2,500 feet AGL is the correct answer is that this configuration is established to provide an adequate buffer for aircraft operations while allowing for effective air traffic control. The relatively low altitude limit also helps manage lower altitude operations, which are typical around busy airports.

Other options present variations in either the radius or the vertical extent that do not conform to the standard dimensions defined for Class D airspace. Understanding these specifics is crucial for pilots preparing to operate in or near such airspaces.