On June 4, 1994, at 1900 mountain daylight time an Air Tractor, Inc., AT-301, N2344T, registered to Dan Barker of Brewster, Kansas, and operated by a commercial pilot, impacted the terrain and was destroyed by impact and a post accident fire while conducting an aerial application. The pilot reported minor injuries. The CFR 14 Part 137 flight was operating in visual meteorological conditions. No flight plan was on file. The local flight departed Brewster, Kansas, at approximately 1840. The pilot stated that during the first swath run he noticed that the airplane performed poorly as he rolled the airplane out onto a north heading. He stated there was a thunderstorm approximately 5-7 miles north and east of his location. He stated he felt he was experiencing a downdraft and attempted to level the wings. He added full power, full RPM, flaps and then dumped his load of chemicals in an attempt to maintain flight; however, these were unsuccessful in maintaining flight. He stated that he attempted to land wings level; however, the left wing collided with the terrain first followed by the nose gear. He stated that when the airplane came to rest a fire had begun and shortly after he exited the airplane it was consumed in the fire. The pilot indicated that there was a light rain occurring at the time of the accident.