Final answer:
A pilot should contact approach control on the appropriate frequency before entering Class C airspace for clearance and traffic advisories to ensure safety and efficient air traffic flow.
Step-by-step explanation:
Before entering Class C airspace, the initial action a pilot should take is to contact approach control on the appropriate frequency. Class C airspace is controlled airspace that surrounds certain airports where air traffic control (ATC) provides radar services.
It is mandated that pilots establish two-way radio communication with the ATC facility providing approach control services before entering this airspace. This is to ensure that air traffic flow is managed efficiently and to enhance safety for all aircraft operating in the area.