Class C airspace requirements, radio contact before entry.

What Class C is

The AIM (3-2-4) defines Class C as generally the airspace from the surface to 4,000 feet above the airport elevation around airports with an operating control tower, radar approach control and a certain number of IFR operations or passenger enplanements. It usually has a 5 nautical mile radius core and a 10 nautical mile shelf that extends no lower than 1,200 feet up to 4,000 feet above airport elevation, with an uncharted outer area normally 20 nautical miles out.

Pilot and equipment requirements

Pilot certification: "No specific certification required." Equipment: a two-way radio; and, unless otherwise authorized by ATC, an operable radar beacon transponder with automatic altitude reporting capability and operable ADS-B Out equipment.

Entry

For arrivals and through flights, "Two-way radio communication must be established with the ATC facility providing ATC services prior to entry and thereafter maintain those communications." A reply of "(aircraft callsign) standby" means communications are established. A reply that omits the aircraft identification means they are not, and the pilot may not enter. If workload prevents service, the controller will tell the pilot to remain outside the Class C airspace.

Departures and speed

Departing a primary or satellite airport with an operating tower, radio communications must be established and maintained with the tower. From a satellite airport without a tower, communication must be established as soon as practicable after departure. Unless authorized or required by ATC, no person may operate an aircraft at or below 2,500 feet above the surface within 4 nautical miles of the primary airport at an indicated airspeed of more than 200 knots (230 mph).

Worked example

A pilot calling "Approach, Skyhawk 123, 15 miles west, 3,500, request Class C service" and hearing "Skyhawk 123, standby" may enter. If the reply is "Aircraft calling approach, standby," the callsign was not used and the pilot may not enter.

Weather minimums are on the Class C VFR weather minimums page.

FAQ

Do I need a clearance to enter Class C?

The AIM requires two-way radio communication to be established before entry, rather than a clearance as in Class B.

Do I need a special certificate in Class C?

No. The AIM says no specific certification is required.

What equipment is required in Class C?

A two-way radio and, unless ATC authorizes otherwise, a transponder with altitude reporting and ADS-B Out.

What is the speed limit near a Class C airport?

At or below 2,500 feet above the surface within 4 nautical miles of the primary airport, no more than 200 knots indicated unless ATC allows.

What if ATC says to remain outside Class C?

Then radio contact is not enough to enter; stay outside until ATC says services can be provided.

Sources

Retrieved 2026-11-02. Regulation text read through the eCFR API (current as of 2026-10-29); AIM text read from the FAA publication URL below. Rules change; check the current text.

• AIM chapter 3, section 2, Controlled airspace (3-2-4): Class C definition, equipment and arrival, through-flight and departure rules.
• 14 CFR 91.155, Basic VFR weather minimums: weather minimums referred to alongside the entry rules.