Definition
A category of controlled airspace surrounding airports that have an operational control tower, are serviced by a radar approach control, and meet a specific threshold of passenger enplanements or instrument operations. Class C airspace typically extends from the surface up to 4,000 feet above the airport elevation, and is generally configured as an inner core with a 5 nautical mile radius from the surface upward, surrounded by an outer shelf with a 10 nautical mile radius starting at 1,200 feet above the airport. Two-way radio communication with ATC must be established before entering, and a Mode C transponder is required.
Plain English
A controlled zone of airspace around medium-sized airports with a control tower and radar service. Pilots must talk to air traffic control and have a working transponder before entering it.
Context Anchor
Seen on sectional charts around busy towered airports and used when planning arrivals, departures, or routes that pass near those airports.
Derivation
“Class” comes from an old word meaning a group or category. In aviation, airspace is grouped into classes with different rules. The letter “C” identifies this specific category of controlled airspace.
Why Pilots Care
Entry requires two-way radio contact with ATC and a transponder with altitude reporting; violations can result in enforcement action and affect traffic separation.
Intuition Check
“Class C” does not mean the airport is third-rate or less important than Class A or B. It means this airspace has its own specific size, services, and entry rules.
Example Sentence 1
Before entering the Class C airspace around the regional airport, the pilot called approach control and waited until the controller responded with the aircraft's call sign.
Example Sentence 2
VFR operations inside Class C Airspace require three miles visibility and cloud clearances of 500 feet below, 1,000 feet above, and 2,000 feet horizontally.