What is the radius and altitude of the inner circle of a Terminal Control Area?

The inner circle of a Terminal Control Area (TCA) typically has a designated radius and altitude that is defined to ensure the safety and efficiency of air traffic operations near airports. The correct choice indicates a radius of 12 nautical miles (NM) and an altitude of 1200 feet above ground level (AGL).

A radius of 12 NM is a common standard for creating a protective airspace around busy airports, allowing aircraft to operate safely while maintaining separation from other traffic. The altitude of 1200 feet AGL is also significant because it marks the limit for where visual flight rules apply, and below this altitude, additional air traffic control regulations come into play to manage lower-level operations, especially around busy terminal areas.

Maintaining an inner circle with these specific parameters helps in managing the flow of traffic into and out of an airport, providing a buffer zone that enhances safety for both departing and arriving flights. The selected radius and altitude serve as regulatory measures to contain the operations effectively without infringing on surrounding airspace, which is crucial for minimizing the risk of midair collisions and ensuring that all aircraft transition safely through this critical area.