Definition
The wingtip vortex generated on the wing positioned into the wind during a crosswind condition. In a crosswind, this vortex tends to remain near the runway surface and stay in place rather than drifting away, creating a wake turbulence hazard for following aircraft.
Plain English
The spinning mass of air shed from the wingtip on the side that the wind is blowing from. Because the wind pushes against it, this vortex tends to hang around near the runway instead of being blown clear.
Context Anchor
Seen in discussions of induced drag, wingtip vortices, wake turbulence, and crosswind operations near a runway.
Derivation
‘Upwind’ means the side facing into the wind (the direction the wind is coming from). So the upwind vortex is simply the vortex on the wingtip that is on the windward side of the aircraft.
Why Pilots Care
The upwind vortex can linger near the runway and create sudden roll or turbulence for following aircraft, requiring increased spacing or adjusted departure paths.
Grounding Statement
Picture a light crosswind across the runway while a larger aircraft lands; the spinning air on the wind-facing side may linger near the runway instead of clearing out right away.
Intuition Check
Upwind does not mean the direction the wind is blowing toward; it means the side the wind is coming from. The upwind vortex is the vortex on that wind-facing side of the aircraft.
Example Sentence 1
With a light left crosswind, the upwind vortex from the departing 737 stayed near the centerline, so the tower extended our spacing.
Example Sentence 2
Controllers noted that the upwind vortex from the departing heavy jet had not yet drifted off the approach path.