Private Pilot License (PPL) Aerodynamics Practice Exam

When are wingtip vortices produced by an aircraft?

1. When the aircraft is descending

2. When the aircraft is taxiing

3. When the aircraft is developing lift

4. When the aircraft is cruising

The correct answer is: When the aircraft is developing lift

Wingtip vortices are a byproduct of lift generation on an aircraft's wings. When an aircraft flies, the pressure difference between the upper and lower surfaces of the wings causes a rotation of air at the tips of the wings. This phenomenon occurs due to the high-pressure air from below the wing flowing around the wingtip to the lower-pressure area above the wing, creating a swirling motion that manifests as vortices. These vortices are most prominent when the aircraft is actively generating lift, such as during takeoff and climbing phases. They can be particularly hazardous to smaller aircraft flying in the wake of larger aircraft, as the vortices can cause turbulence and loss of control if encountered. While descending, taxiing, or cruising, the aircraft's wings may not be producing lift in the same way as during takeoff or climbing. Therefore, the production of wingtip vortices is specifically associated with the lift-generating phases of flight. Understanding this concept is crucial for pilots to maintain safety protocols around larger aircraft in both takeoff and landing scenarios.