Class D Airspace
Class D airspace is generally from the surface to 4,000 ft. above the airport elevation (charted in MSL) surrounding those airports that have an operational control tower. The configuration of each Class D airspace area is individually tailored and when instrument procedures are published, the airspace is normally designed to contain the procedures. Arrival extensions for instrument approach procedures (IAPs) may be Class D or Class E airspace. Unless otherwise authorized, each aircraft must establish two-way radio communication with the ATC facility providing air traffic services prior to enter the airspace and thereafter maintain those communications while within the airspace. If the aircraft radio fails in flight under IFR, the pilot should continue the flight by the route assigned in the last ATC clearance received, or if being radio vectored, by the direct route of radio failure to the fix, route, or airway specified in the vector clearance. In the absence of an assigned route, the pilot should continue by the route that ATC advised may be expected in a further clearance, or if a route had not been advised by the route filed in the flight plan. If the aircraft fails in flight under VFR, the PIC my operate that aircraft and land if weather conditions are at or above basic VFR weather minimums, visual contact with the tower is maintained, and a clearance to land is received.