If two departing aircraft will have 90-degree course divergence immediately after takeoff, what is the earliest time we can release them?

If two departing aircraft will have 90-degree course divergence immediately after takeoff, what is the earliest time we can release them?

• A. 0 Minutes
• B. 1 Minute
• C. 3 Minutes
• D. 5 Minutes

Answer: (B)

Wake turbulence is the key factor shaping when a second departure can be released. The lead aircraft leaves behind wingtip vortices that initially stay close to the departure paths. If the two aircraft diverge by ninety degrees right after takeoff, those vortices move away from the second aircraft’s path fairly quickly, reducing the chance of a wake encounter. Because the divergence helps dissipate and clear the wake sooner, a brief delay before releasing the second aircraft is enough to maintain safe separation. Releasing immediately would risk wake interaction, while waiting longer is more conservative than necessary for this sharp divergence. Therefore, the earliest safe release is after a short delay following takeoff.

Wake turbulence is the key factor shaping when a second departure can be released. The lead aircraft leaves behind wingtip vortices that initially stay close to the departure paths. If the two aircraft diverge by ninety degrees right after takeoff, those vortices move away from the second aircraft’s path fairly quickly, reducing the chance of a wake encounter. Because the divergence helps dissipate and clear the wake sooner, a brief delay before releasing the second aircraft is enough to maintain safe separation. Releasing immediately would risk wake interaction, while waiting longer is more conservative than necessary for this sharp divergence. Therefore, the earliest safe release is after a short delay following takeoff.