Private Pilot License (PPL) Aerodynamics Practice Exam

What happens to wingtip vortices created by large aircraft?

1. They rise above the aircraft

2. They remain stationary

3. They sink below the aircraft

4. They disperse immediately

The correct answer is: They sink below the aircraft

Wingtip vortices are the circular patterns of rotating air that are generated at the wingtips of an aircraft due to the difference in pressure between the upper and lower surfaces of the wing. When an aircraft is in flight, the higher pressure air beneath the wing flows around the wingtips to the lower pressure area above the wing, creating these vortices. As for what happens to these vortices, they tend to sink below the flight path of the generating aircraft after being created. This downward motion occurs due to the weight of the aircraft and the properties of the air involved. The vortices, while initially traveling with the forward motion of the aircraft, gradually lose altitude and can persist in the air for a significant time, depending on factors such as atmospheric conditions and the size and weight of the aircraft that created them. Understanding that wingtip vortices sink below the aircraft is essential for pilots, particularly when taking off or landing. This knowledge helps in maintaining safe distances from larger aircraft to avoid potential wake turbulence, which can lead to loss of control for smaller aircraft if they encounter these descending vortices.