Plain English Meaning

The invisible swirling air an aircraft leaves behind it as it flies. Bigger and slower aircraft leave stronger swirls, and flying into them can flip or upset a smaller aircraft.

Full Definition

The disturbed air left behind a flying aircraft, consisting primarily of two counter-rotating vortices trailing from the wingtips, along with jet engine exhaust, propeller wash, and rotor downwash. These wingtip vortices are a byproduct of the lift the aircraft is producing and can persist for several minutes, sinking and drifting with the wind. Following aircraft that fly into them can experience sudden, severe rolling moments and , especially when the leading aircraft is heavier, slower, and in a .