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Which of the following is an acceptable pilot technique for avoiding a wake turbulence encounter?
  • A
    When departing behind a large aeroplane the following aeroplane should rotate just past the large aeroplane`s rotation point.
  • B
    In the enroute environment when following a large aeroplane, the following aeroplane should fly just below the preceding aeroplane`s flight path.
  • C
    Landing or departing aeroplanes should avoid being on a parallel runway that is upwind from the one being used by large aeroplanes.
  • D
    In the landing pattern the following aeroplane should touch down past the point where the preceding aeroplane touched down.

Refer to figure.


Whenever an airplane generates lift, air spills over the wing tips from the high pressure areas below the wings to the low pressure areas above them. This flow causes rapidly rotating whirlpools of air called wingtip vortices. An aircraft generates vortices from the moment it rotates on take-off to touchdown.

The intensity depends on aircraft weight, speed and configuration. The greatest wake turbulence danger is produced by large, heavy airplanes operating at low speeds, high angles of attack and in a clean configuration.

Although wake turbulence settles, it persists in the air for several minutes, depending on wind conditions. In calm winds, wing tip vortices separate outwards on each side of the runway. In light winds of 3 to 7 knots, the vortices can stay in the touchdown area, sink into your take-off or landing path, or drift over a parallel runway.

General Guides:

  • To avoid turbulence when landing behind a large aircraft, stay above the large airplane’s glide path and land beyond its touchdown point.
  • If a large airplane has just taken-off as you approach, touch down well before the large aircraft’s lift-off point.
  • When departing after a large aircraft has landed, lift-off beyond its touchdown location.
  • When taking-off behind a large aircraft, lift-off before the large aircraft’s rotation point and climb out above or upwind of its flight path.

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