Aviation Communications - Class C Airspace

Class C Airspace Communications

The Figures PDF for these communications articles can be downloaded HERE

The communication procedures in class C airspace are nearly identical to that of Class B. The real difference is in the layout of the control area, and the requirements to enter the airspace. Also, Class C airports usually have clearance delivery as well as approach controllers. Class C airports often do have radar facitilies, but not always.

The ceiling of class C airspace is usually 4,000 feet above airport elevation. The surface to 4,000-foot area is normally a radius of 5 nautical miles from the primary airport. A shelf with a radius of 10 miles from the primary airport exists from 1200 feet agl to 4,000 feet. Some variations may occur in the layout depending on local traffic requirements (see figures 1 and 11). A solid magenta border on VFR sectional charts will identify the boundary of class C airspace.

In addition to the depicted areas surrounding a Class C airport, there is also an area not depicted which is called the "Outer Area". This outer area extends in a 20-miles radius from the primary airport. There are no absolute requirments in the 20-mile area except that a prudent pilot would have contacted approach by that time.

The mode-C veil surrounding class C airspace extends upwards indefinitely from the outer boundary. From the outer boundary to the surface, mode-C must be operated only within the boundaries of the airspace. Obviously this means that you can fly under the outer shelf without mode-C. For more information on mode-C requirements see FAR 91.215.

There are fewer approach control frequencies to a class C airport than there are to a class B, usually one frequency for aircraft approaching from the north for example, and one frequency for aircraft approaching from the south. Of course it could be east and west depending on the runway layout and the direction of traffic flow at the particular airport. The number of frequencies can also vary with traffic density.

It is important to remember to make your initial call to a class C area 20 miles out. Again this is a minimum, and the call will be to approach control on the appropriate frequency. These frequencies can be found in white boxes with solid magenta borders on VFR sectional charts (see figure 11).

The conditions to enter class C airspace are the same as a class D in that you have to establish radio contact. Radio contact is established when the controller responds to you using your call sign. If the controller responds with:

“Aircraft calling Savannah, standby.” Radio contact has not been established and you may not enter the airspace. If the controller responds:

“Piper seven three seven seven mike, Savannah approach, remain outside of charlie airspace.” Radio contact has been established, but still you may not enter the airspace because you have been told to remain clear. If the controller says:

“Piper seven three seven seven mike, Savannah approach.” Radio contact has been established, and you may continue inbound.

Do not wait until the last minute to make your calls, make sure you give the controller plenty of time to sequence you into the traffic pattern.

The approach and departure procedures for a class C area are the same as a class B, so refer to class B approach and departure, for that information. END