AIM ¶ 3-2-5 — Class D Airspace
AIM 3-2-5 explains Class D airspace dimensions, two-way radio entry requirements, speed limits, and part-time tower operations for pilot students.
Class D airspace surrounds airports with an operational control tower and generally extends from the surface up to 2,500 feet above airport elevation (charted in MSL). Each Class D area is individually tailored, and on charts it appears as a blue segmented line on Sectionals and Terminal charts.
Key requirements for student pilots:
- Pilot certification: No specific rating required.
- Equipment: An operable two-way radio (unless ATC authorizes otherwise).
- Entry: You must establish two-way radio communications with the tower before entering. Communications are established when the controller responds using your callsign (e.g., "N123AB, standby"). If the controller says only "aircraft calling tower, standby," comms are NOT established and you may not enter.
- If told to "remain outside the Class Delta airspace and standby," you must stay clear.
- Speed limit: Max 200 knots indicated at or below 2,500 ft AGL within 4 NM of the primary airport.
- No VFR separation services are provided.
Many towers are part-time. When closed, the airspace reverts to Class E or Class G per the Chart Supplement. This matters operationally because your communication and weather minimums change accordingly.
Five FAA-written-style questions. Instant explanations, every answer cites its source — no account needed.
What is required before you may operate an aircraft within Class B airspace?