Class C airports are your larger airports with radar coverage. How busy these airports is harder to judge than Class D airports. For example, KEVV (Evansville, IN) has just a few airline flights a day and most of the traffic is us random general aviation guys. However, KPDX (Portland, OR) is a focus city for Alaska Airlines and a crew base for Horizon Airlines.

Class C airports, depicted with a solid magenta line on sectionals, will have approach/departure control to compliment the tower and offer radar coverage for all. The standard dimensions of Class C airports consist of 2 shelfs (Think upside down wedding cake). The inner shelf (with the airport immediately in it) will be 5 miles in radius, and go from the surface up to 4,000 feet AGL. The outter shelf will extend 10 miles in radius from the center of the airfield, and will generally begin at 1,200 feet AGL and go up to 4,000 feet AGL.  Remember though, each airspace is different. Airspace can always be specifically tailored to meet the needs of an airport.

Before entering Class C airspace, you must have an operable  Mode C (altitude reporting) transponder. The controller must also read back your callsign before you may enter their airspace. As always, before contacting any airspace surrounding an airport, get that airports ATIS/AWOS before calling them up. You’ll save you and the controller time by doing this.

Clearence Delivery
Often Class C airports (like Class B) will have clearance delivery for aircraft on the ground. This prevents congestion on the ground frequency. After starting up (or some FBO’s allow you to call clearance delivery from the inside before starting up) and grabbing the ATIS, instead of contacting ground first, you contact clearance delivery.

N12XYZ: Charlie Clearance, Cessna N12XYZ is in front of [FBO], VFR to [Destination/Direction], requesting [altitude], with information Alpha
Charlie Clearance: N12XYZ,  Fly runway heading until 1,000 feet [MSL], then proceed on course, maintain VFR at or below 2,500 [MSL], Departure frequency will be 125.35, squawk 3012.
N12XYZ: Runway heading until 1,000 feet then on course, maintain VFR at or below 2,500 feet. Departure on 125.35, squawk 3012.
Charlie Clearance: N12XYZ, readback is correct. Contact ground on 121.7 when ready to taxi.
N12XYZ: 121.7, Thanks.

As you can see, there is a lot of information being exchanged back and forth.  You start by calling up the clearance delivery and tell him your intentions of fight. In this specific case, he came back and put some limits on you. He told you to fly runway heading until you reach 1,000 feet (MSL is always implied in ATC instructions).  After you reach 1,000 feet you may proceed on course. This instruction can vary with amount of traffic in the area. If the controller needs you out of the way immediately, he may ask that you turn as soon as you take off (don’t turn until you are roughly 500 feet AGL for safety). He also told you to remain VFR (see and avoid) at or below 2,500 feet. This means that you cannot climb above 2,500 feet until they tell you to, and you are responsible for not hitting anyone.  Usually once you start talking to your departure controller, they will clear you up to your requested altitude assuming there are no traffic conflicts. The trick with clearance delivery is to take your time and write everything down.

Ground/Tower
You got your clearance and are now ready to taxi. The ATIS alerted you of the active runway, so you can roughly guess what your taxi route is going to be. Calling up ground is exactly the same as if you were calling ground in a Class Delta airport. For more on ground control, check out our Class D page here.

Tower at a Class C airport will operate the exact same as a tower at a Class D airport. The only difference is the tower will be busier and may issue a little bit different instructions. He may ask you to turn as a specific altitude or distance after takeoff (even if it’s different than what you got from clearance delivery). Just comply and read back his instructions and you will both be happy. More on tower at our Class D page.

Departure
After taking off and you are clear of tower’s airspace, he will hand you off to the departure controller. It will be a simple hand off:

Charlie Clearance: N12XYZ, contact departure on 125.35.
N12XYZ: Over to 125.35, XYZ. Thanks.

Being the prepared pilot that you are, you already had the departure frequency set in your com2/standby radio. You click over and say:

N12XYZ: Charlie Departure, N12XYZ is with you passing through (or level at) [altitude]
Charlie Departure: N12xyz, roger. Radar contact. Remain VFR at or below [requested altitude]
N12XYZ: VFR at or below [requested altitude], XYZ

It is usually when ATC has you on their radar that they will clear you up to your altitude. Once you have established with the departure controller, you are pretty much done talking. Unless there are any traffic advisories, in which you simply respond to any requests they make (make sure to read back altitudes, headings, or airspeed requests), the controller will terminate your radar services once you are out of his airspace.

Charlie Departure: N12XYZ, radar services are terminated, squawk VFR (or 1200). Good day.
N12XYZ: Squawk VFR, good day, XYZ

Approach
You are now approaching a Class C airport. It is best to contact approach when you are about 15-20 miles out. If you look on a sectional, their will be magenta flags. These flags are predetermined checkpoints that you can use to reference when you call up the approach controller. To the right is an example of one of the flags.

Before you call up the approach controller, make sure you have the latest ATIS. The initial call up on approach is almost identical to calling up the tower at a Class D airport. The only difference is the instructions you will receive after you call up.

N12XYZ: Charlie Approach, N12XYZ is 2 miles east of Mt Vernon (a checkpoint on the sectional), level 5,500, landing at Charlie Airport, with information alpha.
Charlie Approach: N12XYZ, squawk 0504 and ident.
N12XYZ: Squawk 0504, ident for XYZ.
Charlie Approach: N12XYZ, radar contact 20 miles west of Charlie Airport. Descent and maintain 3,000 and remain on course.
N12XYZ: Descent and maintain 3,000 and remain on course, XYZ..

You will now proceed to comply with any instructions given to you. You may be vectored for traffic or given instructions to enter the pattern. You can also ask for vectors to the pattern and work load permitting ATC will vector you to the pattern or to final. The last instruction given to you by Approach will be to contact Tower. When calling up Tower, simply tell him who you are and where you are. He/she will be expecting you as the departure controller alerts him that you are on the way.