Wingtip vortices are created only when an aircraft is

• A. Developing lift
• B. On the ground
• C. Climbing
• D. In cruise

Answer: (A)

Wingtip vortices come from the pressure difference created by a lifting wing. The wing pushes air from underneath to above the wing, and air tends to spill around the wingtips, rolling into a pair of counter-rotating vortices that trail behind the aircraft. This swirling happens whenever the wing is generating lift, so the vortices are present when the airplane is developing lift. On the ground there’s no lift being produced, so vortices don’t form. The stronger the lift, the stronger the vortices, which is why the concept focuses on the wing actively producing lift.