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Vaisala AviMet® Windshear Alert System (LLWAS)

​​​​​​​​​​​​​​​​Vaisala AviMet® Windshear Alert System enables pilots and ATCs to mitigate the risks of windshear safely and intuitively through accurate, easy-to-use information. The Vaisala AviMet® LLWAS informs

  • when there is no windshear
  • when windshear starts
  • when windshear ends.

How does Wind Shear affect landing?



    Windshear is most commonly caused by downdraft-generated microbursts hitting the ground and rapidly spreading in all directions. These unpredictable changes in wind speed and direction make it difficult to control the aircraft, with headwinds, tailwinds and up and down drafts all in quick succession. At worst, it can cause a sudden and dramatic loss in altitude resulting in a serious accident.

    Airports prone to horizontal low-level windshear require accurate and timely warnings to ensure passenger safety and comfort during take-off and landing. Vaisala’s windshear warning solution delivers this crucial information in a timely and consistent manner. The Vaisala solution also decreases the burden on air traffic controllers by informing them immediately when and where windshear occurs and when the threat is over. The solution increases air traffic controllers’ decision-making confidence as decisions are based on facts, allowing them to issue timely and reliable advance warnings to pilots.



    The Vaisala AviMet® LLWAS offers aviation authorities the ability to dramatically improve aviation safety, the landing minima, and all weather traffic density with a low investment budget.

    The LLWAS is the first choice stand-alone windshear detection system for airfields where weather radars cannot be considered due to budget constraints. On the other hand, the system can be integrated with TDWR systems as well to provide the ultimate quality for windshear detection. According to the National Center for Atmospheric Research, the highest quality windshear warnings are achieved by integrating the results of a Phase III Low Level Windshear Detection System and a Terminal Doppler Weather Radar. To achieve this integration, the Vaisala AviMet® LLWAS is able to output data to a radar system.

    The Vaisala AviMet® LLWAS is the newest ground based Windshear Alert System that incorporates the latest version of the phase III windshear algorithm developed for the U.S. Federal Aviation Administration (FAA) and patented by the University Corporation for Atmospheric Research Foundation (UCAR).

    The vast research on the windshear and microburst phenomena results in reliable alerts and warnings conveyed unambiguously to the operator on the LLWAS numeric and graphic displays. To generate crucial windshear alerts and warnings, the LLWAS system retrieves constantly wind data from an array of wind sensors surrounding the runway. The wind sensor array is carefully positioned and aligned in accordance with the MIT, Lincoln Laboratories and the National Center for Atmospheric Research system design guidelines to provide the maximum system reliability.

    The Phase III windshear system is the result of many years of development in microburst alert research and represents the best technology currently available. The increased detection capabilities coupled with the low false alarm rates makes the Phase III system a clear choice over the older Phase I and II systems. Not only does the Vaisala AviMet® LLWAS use the best available algorithms in the world, it is newly designed and built to provide the user with the most advanced and reliable information on low level windshear and microbursts.



    Services are an essential part of successful implementation of windshear solution. Our service offering includes:

    • Customer requirement definition and consulting
    • Solution design and solution delivery
    • Solution installation, commissioning, testing and training
    • Life-cycle services
    • Other life-cycle service elements
    Vaisala windshear concept