What must be maintained when separating aircraft from other aircraft at or above FL600?

Maintaining a separation of 10 miles is crucial for aircraft flying at or above Flight Level 600. This is due to the increased complexities and risks associated with high-altitude operations, where aircraft speeds can be greater and the potential for operational conflicts is heightened. At such altitudes, the airspace is generally less congested, but the high speeds mean that even a small error can lead to a significant overlap in flight paths.

The 10-mile separation rule ensures a safety buffer that accounts for the speed of aircraft and allows for ample reaction time in the event of any changes in flight path. This standard separation distance helps controllers manage the airspace effectively and enhances overall flight safety at these altitudes. Consequently, maintaining this level of separation is essential for preventing loss of separation and ensuring smooth and safe air traffic control at high altitudes.