The intensity of wingtip vortices depends on the airplane's weight, speed, and configuration.

• A. Altitude, color, and wing span
• B. Weight, speed, and configuration
• C. Engine type, cabin pressurization, and fuel load
• D. Air temperature, humidity, and flight phase

Answer: (B)

Wingtip vortex intensity tracks the amount of lift a wing is producing. Heavier airplanes need more lift, so at the same speed they generate stronger vortices. If you fly the same weight but slower, you must produce more lift (higher lift coefficient), which also strengthens the vortices. The wing configuration—such as flap settings or gear position—changes the lift capability and wing loading, so it directly adjusts vortex strength.

Other factors listed don’t directly set how much lift the wing is generating, so they don’t determine vortex intensity in the same way. Altitude or wing span can influence where vortices form or how long they persist, engine type, cabin pressurization, and fuel load don’t directly change lift in a way that would set vortex strength, and air temperature, humidity, or flight phase mainly affect density and decay rather than the lift-produced strength itself.

So weight, speed, and configuration are the primary determinants of wingtip vortex intensity.