Class D airspace

Class D airspace surrounds airports that have an operating control tower but little or no radar service of their own. It's usually a modest cylinder about 4 nm in radius extending from the surface up to roughly 2,500 ft above the airport (the exact top is charted). When the tower closes, the airspace typically reverts to Class E or G.

The entry rule mirrors Class C: establish two-way radio communication with the tower before entering, and you're in once the controller acknowledges you by call sign. No transponder is required by Class D itself (though nearby Class B/C veils may require one). There's no separation service for VFR traffic — the tower sequences arrivals and departures and issues traffic advisories as workload permits.

VFR weather minimums are the standard 3 statute miles visibility with 500 below / 1,000 above / 2,000 horizontal cloud clearance. When the field is below VFR minimums you'll need a special VFR clearance or an IFR clearance to operate.

Class D is shown on sectionals with a dashed blue line, and the ceiling appears in a small bracketed number (e.g. `[25]` = 2,500 ft MSL). Copy the ATIS and call the tower with your position and request before you reach the boundary.

*Reference and training only. Consult current charts and the FAA AIM.*