Class C airspace surrounds busier airports that have a control tower and a radar approach control. It usually has a 5 NM core from the surface to 4,000 feet above the airport and a 10 NM shelf from 1,200 to 4,000 feet above the airport, charted with solid magenta lines. To enter, you must establish two-way radio communication with approach control first, your aircraft needs a Mode C transponder and ADS-B Out, and the VFR weather minimums are 3 statute miles visibility and 500 feet below, 1,000 feet above and 2,000 feet horizontally from clouds.
This guide is part of our Airspace and Weather guide. If you have not flown into a towered field yet, start with Class D airspace, then come back here.
Class C airspace structure
AIM 3-2-4 defines Class C as airspace generally from the surface to 4,000 feet above the airport elevation (charted in MSL) around airports with an operational control tower, a radar approach control, and a certain number of IFR operations or passenger enplanements. FAA design guidance (Order JO 7400.2, paragraph 16-2-3) starts every Class C as two concentric circles, which gives the familiar upside-down wedding cake:
- Core (surface area): a 5 NM radius from the surface up to 4,000 feet above the airport.
- Shelf: from 5 to 10 NM, beginning no lower than 1,200 feet AGL and extending up to the same 4,000-foot ceiling. Below the shelf you are outside Class C.
- Outer area: normally 20 NM from the primary airport. It is a procedural area, not Class C airspace, and it is not charted. Approach control offers Class C services there, but participation is voluntary.
Those numbers are the starting point. Terrain, nearby airports and traffic flows lead to cutouts and odd-shaped sectors, so the chart always wins over the rule of thumb.
How Class C looks on a sectional chart
Per the FAA Aeronautical Chart Users’ Guide, Class C is drawn with solid magenta lines, and each sector shows its ceiling over its floor in magenta figures, in hundreds of feet MSL with the last two zeros dropped. “48 over SFC” means surface to 4,800 feet MSL; “48 over 20” means 2,000 to 4,800 feet MSL. A ceiling of “T” means the Class C goes up to, but not including, the floor of overlying Class B. Magenta boxed notes give the approach control frequencies arriving VFR pilots should use, and a note marks any Class C that operates part-time. Practice reading them in our sectional chart guide, and keep a current chart onboard; PilotMall stocks VFR sectional charts.
When the chart shows more than one approach frequency for a Class C, the boxed note tells you which one applies to your arrival sector. Write that frequency and the ATIS frequency on your kneeboard before you get within about 20 NM, so the call goes out well before the shelf.
Entering Class C: radio contact first
14 CFR 91.130(c)(1) requires you to establish two-way radio communication with the ATC facility providing service before entering, then keep it while inside. AIM 3-2-4 tells arriving pilots to call approach control on the published frequency and give their position, altitude, radar beacon code (if one is assigned), destination, and request Class C service. The same entry test applies as in Class D:
- “Skyhawk One Two Three Four Five, standby.” Your call sign was used, so communication is established and you may enter.
- “Skyhawk One Two Three Four Five, remain outside the Class Charlie airspace and standby.” Established, but do not enter until told otherwise.
- “Aircraft calling Springfield Approach, standby.” No call sign, no communication. Stay outside.
Departing the primary airport or a satellite with a tower, you talk to the tower and then follow ATC instructions. Departing a satellite without a tower, you contact the facility having jurisdiction as soon as practicable after takeoff (91.130(c)(2)).
What approach control does for you
Once you are in radio and radar contact, AIM 3-2-4 says VFR aircraft are sequenced to the primary airport, provided Class C services within the Class C and the outer area, and separated from IFR aircraft by visual separation, 500 feet vertical separation or target resolution. None of that relieves you of seeing and avoiding traffic, avoiding wake turbulence, staying clear of terrain, or keeping basic VFR weather minimums. If an assigned heading or altitude would put you in a cloud, tell the controller and get a new instruction.
Equipment: radio, Mode C and ADS-B Out
Unless ATC authorizes otherwise, 91.130(d) requires the equipment in 91.215 and 91.225:
- Two-way radio for the communication requirement.
- Transponder with Mode C altitude reporting in Class C airspace and in all airspace above the ceiling and within the lateral boundaries of the Class C, up to 10,000 feet MSL (91.215(b)(1) and (b)(4)).
- ADS-B Out meeting 91.225(b) in the same airspace: inside Class C and above its ceiling within its lateral boundaries up to 10,000 feet MSL (91.225(d)(1) and (d)(3)).
The requirement does not extend underneath the shelf, so an aircraft without a transponder may fly below a Class C shelf, unless that spot is also inside a Class B Mode C veil or another part of 91.215 applies. If your aircraft lacks a transponder or ADS-B Out entirely, a deviation request must reach the controlling facility at least one hour before the flight. A portable ADS-B receiver only receives; it does not count as ADS-B Out (see our portable ADS-B receiver guide).
Speed limit in Class C
Under 91.117(b), unless ATC authorizes or requires otherwise, you may not exceed 200 knots indicated at or below 2,500 feet above the surface within 4 NM of the primary airport of a Class C area. Elsewhere below 10,000 feet MSL the 250-knot limit of 91.117(a) applies.
Class C weather minimums
Class C uses the same basic VFR minimums as Class D (91.155):
| Requirement | Class C |
|---|---|
| Flight visibility | 3 statute miles |
| Distance from clouds | 500 ft below, 1,000 ft above, 2,000 ft horizontal |
| Ceiling in the surface area | At least 1,000 ft to fly beneath it under VFR (91.155(c)) |
| Takeoff, landing or entering the pattern | Ground visibility at least 3 SM, or flight visibility 3 SM if none is reported (91.155(d)) |
Below those minimums the option is a special VFR clearance, which some busy Class C surface areas do not allow for airplanes (they are listed in part 91 appendix D, section 3, and marked on charts). See every class compared in our VFR weather minimums guide.
Satellite airports under Class C
Any airport inside a Class C other than the primary is a satellite airport (91.130(a)). Section 91.130(b) says you may take off or land at a satellite only in compliance with FAA arrival and departure traffic patterns, and the communication rules above still apply: talk to approach before you enter the Class C to reach the satellite, and contact approach as soon as practicable after departing an untowered satellite. Approach will terminate Class C service early enough for you to switch to the satellite’s tower or CTAF. Where a towered airport’s Class D sits under the Class C, parts of the Class C may be procedurally excluded while that tower is open, and you communicate with that tower directly.
What you'll need
Plan Class C arrivals with current references and keep your frequencies within reach.
Student pilots in Class C
Class C has no pilot certificate requirement (AIM 3-2-4). A student working toward a private certificate needs no separate Class C endorsement under the regulations, but flies solo only within the instructor’s endorsements and any logbook limitations (61.89(a)(8)). Students seeking a sport or recreational certificate need the ground and flight training and endorsement in 61.94 before operating in Class B, C or D airspace. Ask your instructor to include a Class C arrival in your dual cross-country training so the first solo one feels routine.
Sample Class C radio calls
Listen to the ATIS first, then call approach well outside the shelf:
- You: “Springfield Approach, Skyhawk One Two Three Four Five, eighteen miles north at four thousand five hundred, landing Springfield with information Charlie, request Class C service.”
- Approach: “Skyhawk One Two Three Four Five, Springfield Approach, squawk zero four three one.” Your call sign was used, so communication is established.
- You: “Squawk zero four three one, Skyhawk One Two Three Four Five.”
- Approach: “Skyhawk One Two Three Four Five, radar contact one seven miles north of Springfield. Proceed direct the airport, maintain VFR.” Later: “Contact Springfield Tower one one eight point three.”
- You: “Tower one one eight point three, Skyhawk One Two Three Four Five.” Then call the tower with your position, just as you would in Class D.
Departing the primary airport, tell ground control your direction of flight with the ATIS letter; expect a squawk code and a departure frequency. Our towered airport communications guide and phraseology guide cover the wording, and the Class B airspace guide covers the next step up, where you need an explicit clearance.
Frequently asked questions
What are the dimensions of Class C airspace?
Usually a 5 NM core from the surface to 4,000 feet above the airport, plus a shelf from 5 to 10 NM that starts no lower than 1,200 feet AGL and reaches the same ceiling. A procedural outer area normally extends to 20 NM but is not Class C airspace.
Do you need a clearance to enter Class C airspace?
No. You need two-way radio communication established with approach control before entering. If the controller replies with your call sign, communication is established, unless you are told to remain outside.
Do you need a transponder to fly above Class C airspace?
Yes. A Mode C transponder and ADS-B Out are required in all airspace above the ceiling and within the lateral boundaries of Class C, up to 10,000 feet MSL, under 14 CFR 91.215(b)(4) and 91.225(d)(3).
Can you fly under a Class C shelf without talking to ATC?
Yes. The airspace below the shelf floor is not Class C, so no radio contact, transponder or ADS-B Out is required by the Class C rules, unless that area is inside a Class B Mode C veil or another requirement applies.
What is the speed limit in Class C airspace?
200 knots indicated at or below 2,500 feet above the surface within 4 NM of the primary airport, unless ATC authorizes or requires otherwise. Elsewhere below 10,000 feet MSL the limit is 250 knots.