Which statement is true about wingtip vortices?

• A. They can sink up to 900 feet and up to 200 feet near the ground.
• B. They can sink up to 1,500 feet and 400 feet near the ground.
• C. They can sink up to 2,000 feet and 600 feet near the ground.
• D. They always dissipate immediately and do not affect following aircraft

Answer: (A)

Wingtip vortices are the rotating air behind a wing that create a strong downward flow in the wake. This downward motion can be quite rapid, up to about 900 feet per minute in still air, and the vortices can descend well below the generating aircraft’s altitude. As they approach the ground, the lower portion of the wake is limited by the surface, typically reaching within roughly 200 feet of the ground before dissipating or mixing with the surrounding air. Because they linger and drift with winds, wake turbulence can affect following aircraft long after the generating airplane has passed. The idea that they dissipate immediately isn’t correct, and the specific numbers in some options are outside the common ranges for peak descent rates and near-ground extent.