For maintaining separation, what is the minimum required separation in nautical miles for an aircraft speed differential of 75 knots?

To determine the minimum required separation in nautical miles for an aircraft speed differential of 75 knots, one must apply the principles of air traffic management that govern the safe stacking and spacing of aircraft.

When aircraft are flying in the same direction, a general rule applies where a certain distance is required for every increment of speed differential to ensure safe separation. Specifically, for a speed differential of 75 knots, the guidance typically advises a separation of 1.25 nautical miles. This distance accounts for the increased closing speed and gives air traffic controllers a margin to manage the relative positions of each aircraft effectively.

This guideline is in place to minimize the risk of wake turbulence encounters and to allow for adjustments should an aircraft need to change course or altitude. Implementing a distance that is too small could potentially lead to conflicts, especially in busy airspace.

In summary, the minimum required separation for maintaining safe operations, given the condition of a 75-knot speed differential, is established as 1.25 nautical miles, making it the correct choice among the provided options.