Large changes in wind velocity and/or direction occurring over relatively small distance produce an atmospheric condition known as wind shear. A change in wind direction produces a wind shear even when there is no change in velocity. Changing winds will alter ground speed, and inertia will resist those changes. The effect of groundspeed inertia causes an increasing headwind to increase an aircraft's airspeed, which in turn disrupts the equilibrium of forces acting on the aircraft and results in a requirement to readjust power and trim to maintain a desired flight path. For several reasons, wind shear has only recently been identified as a factor in accidents: Better identification techniques; higher approach speeds; and, better records of what occurred. In simulated studies, the rapid application of power and pitch-up maneuvering appeared to be fundamental elements in recovery from wind shear. The most important factor identified in successful maneuvering was the promptness with which corrective action was taken. The key to early recognition of wind shear is a through understanding of the phenomenon and the weather systems that generate it. The discovery of the spearhead and downburst phenomena is important because recognition of the spearhead can lead to early warning of developing downburst situations. Runways and approach paths can be changed and, when necessary, airports can be closed until the danger passes. Ground-based wind shear detection and forecasting and advisory service are two of the available means of finding wind shear. Airborne wind shear detection systems compare airspeed to ground speed or compare the wind component at the aircraft's position with the wind at the landing area.

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  • Corporate Authors:

    Ziff Davis Publishing Company

    1 Park Avenue
    New York, NY  United States  10016
  • Publication Date: 1978-7

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Filing Info

  • Accession Number: 00179302
  • Record Type: Publication
  • Source Agency: Business and Commercial Aviation Magazine
  • Files: TRIS
  • Created Date: Sep 14 1978 12:00AM