 All aircraft entering class C airspace must establish two-way radio communication with ATC prior to entry; explicit clearance to enter is not required, however the controller of Class C space may instruct aircraft initiating communication to "remain outside" the airspace.The aircraft must be equipped with a two-way radio and an operating Mode C (altitude reporting) radar transponder, furthermore aircraft overflying above the upper limit of class C airspace upward to 10,000 feet MSL must have an operating Mode C transponder.VFR flights in class C airspace must have three miles (5 km) of visibility, and fly an altitude at least below, above, and laterally from clouds.