What is the minimum longitudinal separation required when using the 44-knot rule?

The minimum longitudinal separation required when using the 44-knot rule is based on ensuring a safe distance between aircraft that are flying at different speeds. In this context, the 44-knot rule states that for aircraft flying at a speed of 44 knots, a minimum separation of 5 miles or 3 minutes is necessary. This rule is designed to maintain adequate spacing between aircraft to prevent potential wake turbulence issues and ensure safe navigation in the airspace. When two aircraft are flying in the same direction, understanding both the speed and the necessary separation allows air traffic controllers to manage their spacing effectively, particularly in busy air routes. Thus, the correct answer emphasizes that 3 minutes or 5 miles of separation is essential for safety when using the 44-knot guideline.