How much longitudinal separation is needed when applying the 22-knot rule?

The 22-knot rule is used in air traffic control to determine the required longitudinal separation between aircraft, particularly when managing descending or climbing aircraft with significant speed differences. When one aircraft is overtaking another, specifically at a closure rate of 22 knots, a separation of 5 minutes is needed. We derive the distance separation by multiplying the closure rate by the time, which in this case translates to 10 nautical miles (5 minutes at 2 nautical miles per minute). This separation ensures a safe margin between the aircraft, preventing any potential conflicts as one aircraft overtakes another.

The other options provide different times and corresponding distances that do not align with the required separation based on the 22-knot approach, making them inappropriate for this context.