Definition
A wind of low velocity blowing from behind the aircraft at an angle, rather than directly down the runway. In wake turbulence avoidance, it is the most hazardous wind condition during takeoff or landing because it can move the upwind wingtip vortex of a preceding aircraft laterally onto the runway and hold the downwind vortex over the runway surface, exposing a following aircraft to both vortices.
Plain English
A gentle wind coming from behind you and slightly off to one side. It is the worst wind for wake turbulence because it can push the swirling air left behind by another aircraft onto your runway and keep it there.
Context Anchor
Seen in takeoff, landing, and wake turbulence discussions, especially when considering how wingtip vortices may move near a runway.
Derivation
Quartering comes from the nautical term for a direction roughly 45 degrees off the stern of a ship — a wind from the rear quarter. Aviation borrowed the term to describe a wind blowing diagonally from behind the aircraft.
Why Pilots Care
It can push wingtip vortices from a preceding aircraft across the runway or flight path, increasing the risk of wake encounter.
Grounding Statement
Picture a gentle breeze pushing from behind one shoulder instead of squarely from behind your back.
Intuition Check
Do not read “light” as meaning unimportant. Even a gentle quartering tailwind can matter when it moves wake turbulence into your path.
Example Sentence 1
With a light quartering tailwind reported and a heavy jet just departed, the pilot extended spacing before beginning the takeoff roll.
Example Sentence 2
The tower advised of a light quartering tailwind that could move the preceding aircraft's wake across the approach path.