What is the typical horizontal radius of a Terminal Control Area of Responsibility, centered on the busiest airport?

The typical horizontal radius of a Terminal Control Area (TCA) surrounding a busy airport is generally established to ensure that air traffic control can effectively manage aircraft operations in the vicinity of the airport. A radius of 26 miles strikes a balance between providing a manageable airspace for controllers and accommodating the volume of air traffic that approaches and departs from busy airports.

This distance allows controllers to adequately space aircraft during takeoff, approach, and landing, which is critical for maintaining safety and efficiency in busy terminal environments. The TCA is designed to encompass the airspace where aircraft are most likely to transition to and from higher altitude en-route airspace, making it crucial for maintaining organized traffic flow near high-density airports.

While other options may be common in different contexts or regions, the 26-mile radius specifically refers to the airspace structure around major hubs, aligning with regulatory standards and practices established by aviation authorities.