If two aircraft depart on runways with flight paths crossing and are separated by 2,500 feet, what is the required wake turbulence separation?

• A. 3 minutes
• B. 2 minutes
• C. 1 minute
• D. No separation

Answer: (B)

Wake turbulence is the air disturbance left by a leading aircraft that can affect a following aircraft. When flight paths cross, controllers use wake separation minima that depend on aircraft weight and the geometry of the paths. With two intersecting runways that are about 2,500 feet apart in their flight paths, the standard minimum wake turbulence separation is two minutes. This time allows the vortices to move away from the trailing aircraft’s path so the follower won’t encounter the strongest part of the wake. The two-minute rule reflects a balance between safety and efficiency for this configuration.