What is the expected effect that a 1 to 5 KT crosswind will have on wake vortices?

What is the expected effect that a 1 to 5 KT crosswind will have on wake vortices?

• A. Increase both vortices movement equally.
• B. Decrease or stall the movement of one, while increasing the movement of the other.
• C. Eliminate wake vortices.
• D. Have no effect on wake vortices.

Answer: (B)

Wake vortices are a pair of counter-rotating circulations that trail behind an aircraft. A crosswind pushes the pair sideways, but the two vortices don’t respond identically because they are separated and interact with each other and with the surrounding wind shear. This causes differential advection: one vortex is carried more strongly with the crosswind, while the other’s movement is reduced or effectively slowed. The result is unequal motion between the two vortices, not equal acceleration of both, not elimination, and not no effect.

Wake vortices are a pair of counter-rotating circulations that trail behind an aircraft. A crosswind pushes the pair sideways, but the two vortices don’t respond identically because they are separated and interact with each other and with the surrounding wind shear. This causes differential advection: one vortex is carried more strongly with the crosswind, while the other’s movement is reduced or effectively slowed. The result is unequal motion between the two vortices, not equal acceleration of both, not elimination, and not no effect.