Windshear - The Invisible Threat

Windshear is most commonly caused by downdraft-generated microbursts hitting the ground and rapidly spreading in all directions. Air Traffic Controllers (ATCs) and pilots find it difficult to detect low level windshear. These unpredictable changes in wind speed and direction, with headwinds and tailwinds in quick succession, make it difficult to control the aircraft. At worst, it can cause a sudden and dramatic loss in altitude resulting in a serious accident.

The Vaisala AviMet LLWAS was specifically designed to measure and report wind shear of 15–30 knots and microbursts of over 30 knots up to 1000 feet above ground level. The AviMet LLWAS includes wind speed and direction sensors that are sited around the runway area and connected to an on-site data collection unit. The filtered wind data from these sites are interpreted by the AviMet LLWAS algorithm to identify divergence or convergence, and to estimate the effects of the wind shear on aircraft. The sensors are placed high enough to avoid local wind interference, 15 to 30 m above the ground. The wind shear data can be displayed in one of two formats – either as text or graphically. Wind shear alerts are presented visually and audibly. The graphical display depicts the areas of wind shear in relation to the active runway(s).

To improve windshear situational awareness outside of the immediate airport area, Vaisala’s LLWAS now includes a web-based, real-time display of Global Lightning Dataset GLD360 data. Lightning events can be seen within a 500-km radius from the airport. Windshear watches are issued when lightning indicates that thunderstorms are close enough to the airport to potentially produce low-level windshear. This data can be used by air traffic controllers to anticipate potential thunderstorm-induced, windshear events at the airport and alert aircraft about the danger.

Airports prone to horizontal low level windshear require accurate and timely warnings ensure safe take-offs and landings. Vaisala’s windshear warning solution delivers this crucial information in a timely, consistent, and easy-to use manner. The Vaisala solution also decreases the burden on ATCs 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.

With more than 1500 airport weather systems installed in over 90 countries, Vaisala has the technology, experience and contacts to provide solutions for all kinds of airports, anywhere. Vaisala’s LLWAS - the most cost efficient option available on the market.