During radar operations, what should the separation from the edge of airspace be when more than 40 miles away from the radar?

In radar operations, maintaining appropriate separation distances from the edge of airspace is crucial for ensuring safe aircraft navigation and operations. When more than 40 miles away from the radar, a separation of 5 miles from the edge of airspace is established to provide a buffer zone that mitigates the potential risks associated with radar coverage limitations and other factors that affect situational awareness.

This 5-mile separation is designed to account for the radar's ability to accurately track and communicate with aircraft, as well as to account for any potential discrepancies or errors in positioning. It ensures that aircraft remain well within controlled airspace, thereby reducing the likelihood of conflicts or incursions into adjacent airspace that could lead to safety issues.

The other options suggest shorter distances that would not adequately cover the necessary buffer zone required at such distances from the radar, potentially increasing the risk of airspace violations or miscommunication in tracking aircraft. Thus, the specified distance of 5 miles is critical for maintaining a high safety standard in radar operations.