Which configuration produces the strongest wake vortices?

• A. Heavy, clean, and slow
• B. Light, clean, and slow
• C. Heavy, dirty, and fast
• D. Light, dirty, and fast

Answer: (A)

Wake vortices form from the lift produced by the wings, and their strength grows with how much lift the wings generate. A heavier aircraft must generate more lift to stay aloft, so its wingtip vortices are stronger. Flying slower means the wings must operate at a higher lift coefficient to support the same weight, which also increases the circulation and strengthens the vortices. A clean configuration (no high-lift devices deployed) lets the wings generate lift in their most efficient, undisturbed way, producing more intense vortices than if flaps or landing gear are extended. So the combination of heavy weight, slow speed, and a clean configuration yields the strongest wake vortices. Conversely, light, fast, or dirty configurations produce weaker wake due to reduced lift or altered wake structure.