MOSES LAKE — Aerial pesticide applicators from across the state flocked to a landing strip at Northwest Ag Services in Moses Lake Thursday for an annual “fly-in” inspection of applicator efficiency and efficacy led by the Association of Washington Aerial Applicators (AWEA).

For the test, inspectors hung a thin string across an open field and positioned a number of cards nearby. One after another, fixed-wing aircraft and helicopters hurtled at high speeds low to the ground and dumped loads of water mixed with red fluorescent dyes onto the cards and line located just feet below.

The two types of aircraft are used for different reasons: fixed-wing aircraft carry a larger load and their spray pattern spreads farther, while helicopters can make sharper turns at slower speeds, allowing for greater accuracy – useful for applications that come close to sensitive areas like roads, wetlands or another person’s field.

After application, the string and cards that were doused in red dye were analyzed by technicians from the AWEA and the Washington Department of Agriculture.

The string test shows how evenly the spray was applied along a lateral line, with a perfect application showing a smooth gradient with gradually declining spray further away from where the aircraft flew overhead. Analysts can take the data provided by this test and inform pilots of the optimal height from which to spray, in order to minimize the variation in application.

Cards are also analyzed to show the size of droplets sprayed by the aircraft. Too large, and the application isn’t spread as widely; too small, and the droplets can evaporate or drift far afield. Though state regulators are leaning toward requiring such tests, attending a fly-in is currently mostly a matter of self-improvement, said Fred Meise, owner of Northwest Ag Services. “We just do it so we can make our airplanes do a better job, making sure we have a good pattern and that it’s calibrated,” said Meise.

Local state lawmakers attended the event as well, including Sen. Judy Warnick, R-Moses Lake, and Rep. Tom Dent, R-Moses Lake. Dent, who spent much of his life as a commercial pilot, also hopped into a number of aircraft while attending.