Wingtip vortices created by large aircraft tend to

• A. Rise above the aircraft generating turbulence
• B. Stay near the same level
• C. Sink below the aircraft generating turbulence
• D. Move forward ahead of the aircraft

Answer: (C)

Wingtip vortices form when an aircraft generates lift, creating a pair of counter‑rotating tubes of swirling air that trail behind the wings. Air flows from beneath the wing outward around the wingtips to the upper surface, and the resulting circulation gives the vortices a downward component. As the wake develops, these vortices descend, so they tend to sink below the level of the aircraft that created them. They don’t rise above, stay level with, or move forward ahead of the generating aircraft, which is why the wake remains behind and below the airplane.