Class D Airspace
The airspace around a towered airport — establish two-way radio, and know what happens after the tower closes.
Key Takeaways
- Class D surrounds an airport with an operating control tower but without the radar-separation role of Class C.
- It is a small cylinder, roughly 4 NM in radius, from the surface up to about 2,500 ft AGL (charted in MSL).
- You must establish two-way radio communication before entering — no clearance or transponder is required.
- VFR minimums are the standard 3-152: 3 SM visibility, 500 below, 1,000 above, 2,000 horizontal.
- When the tower closes, the airspace usually reverts to Class E or Class G — check the chart supplement for hours.
What Is Class Delta?
Class D (“Delta”) airspace exists wherever there is an operating control tower that is not busy enough for Class C radar separation. It is the simplest towered airspace: a modest cylinder around the field, keeping arrivals, departures, and pattern traffic organized by the tower controller.
Like Class C, you enter by establishing two-way radio communication — not by getting a clearance. And there is a wrinkle unique to Delta: many Class D towers are part-time. When the tower closes for the night, the Class D typically becomes Class E (or Class G) airspace, and the communication requirement goes away. The chart supplement lists the tower’s hours.
Class Delta at a Glance
Class Delta VFR Weather Minimums
3 statute miles
500 ft below · 1,000 ft above · 2,000 ft horizontal ("3-152")
These come from 14 CFR 91.155. See how Class Delta compares to every other class in the full VFR weather minimums table.
See Class Delta on a live chart
FlightKit’s interactive sectional shows Class Delta boundaries, floors, and ceilings on the real chart — and the airspace module pairs the FAA diagram with quizzes so it sticks before your checkride.
The Other Airspace Classes
Frequently Asked Questions
What do you need to enter Class D airspace?
You must establish two-way radio communication with the control tower before entering. No clearance and no transponder are required (unless you are inside a Mode C veil or at or above 10,000 ft MSL). Once the tower responds with your call sign, you may enter.
What are the VFR weather minimums for Class D?
Class D uses the standard "3-152" minimums: 3 statute miles of visibility, and 500 feet below, 1,000 feet above, and 2,000 feet horizontally from clouds — the same as Class C and Class E below 10,000 ft.
What happens to Class D when the tower closes?
When a part-time tower closes, the Class D airspace normally reverts to Class E or Class G, and the two-way radio requirement no longer applies. Always check the chart supplement for the tower’s hours and what the airspace becomes after hours.
Do I need a transponder in Class D?
Not for the Class D itself. A transponder and ADS-B Out are only required in Class D if it also lies within a 30 NM Mode C veil around a Class B airport, or if you climb to 10,000 ft MSL or above.