The Low-Level Wind Shear Alert System (LLWSAS)
Final rept. Jan 1977-Mar 1979
NATIONAL AVIATION FACILITIES EXPERIMENTAL CENTER ATLANTIC CITY NJ
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The results of the Low-Level Wind Shear Alert System LLWSAS field test and evaluation are reported. The system is a computer controlled anemometer mesonetwork used to detect near-surface wind discontinuities associated with strong thunderstorms and cold fronts -- those that are potentially hazardous to low-flying aircraft. The test and evaluation was conducted at seven major airports in the United States. This report discusses the principal meteorological events that will trigger alarms, the system hardware and software, and characteristics of the system that are unique to each airport. Heavy emphasis is placed on the proper siting of anemometry which was found to be the most important factor influencing high quality system performance. The siting criteria enumerated should serve as a model for future installations. Deviations from the model will severely impact system performance. The origin and justification for the vector difference threshold is discussed as well as LLWSAS by-products wind gust determination and special displays for Terminal Radar Approach Control Facility TRACON rooms.
- Terminal Flight Facilities