On August 1, 2007, about 0915 central daylight time, an Air Tractor AT-502B, operated by Keller Flying Service, and piloted by a commercial pilot, sustained substantial damage during an aborted landing on runway 17 (4,018 feet by 75 feet), at the Hampton Municipal Airport (HPT), Hampton, Iowa. The 14 CFR Part 137 aerial application flight was operating in visual meteorological conditions without a flight plan. No injuries were reported. The local flight originated at an unconfirmed time. The pilot stated that while landing on runway 17 at HPT the winds were about 20 knots from the southwest. He said that just as he was touching down the wind speed decreased, which resulted in the airplane yawing to the right. He said that the tires began to skip and he applied power to execute a go-around. He stated that as he crossed the ditch along the right side of the runway the airplane settled to the ground and the left wing tip struck the ditch. The airplane subsequently spun to the left, the right landing gear collapsed, and the airplane slid across the runway.