Hazards
Wingtip vortices can pose a hazard to aircraft, especially during the landing and takeoff phases of flight. The intensity or strength of the vortex is a function of aircraft size, speed, and configuration (flap setting, etc.). The strongest vortices are produced by heavy aircraft, flying slowly, with wing flaps and landing gear retracted ("heavy, slow, and clean"). Large jet aircraft can generate vortices that can persist for many minutes, drifting with the wind.
The hazardous aspects of wingtip vortices are most often discussed in the context of wake turbulence. If a light aircraft is immediately preceded by a heavy aircraft, wake turbulence from the heavy aircraft can roll the light aircraft faster than can be resisted by use of ailerons. At low altitudes, in particular during takeoff and landing, this can lead to an upset from which recovery is not possible. Air traffic controllers attempt to ensure an adequate separation between departing and arriving aircraft, and issue wake turbulence cautions to pilots.
Read more about this topic: Wingtip Vortices