On August 21, 2002, approximately 1600 Pacific daylight time, an Aero Commander S2R "Thrush", N8870Q, sustained substantial damage while on landing roll at Connell City Airport, Connell, Washington. The airplane is registered to B & R Crop Care of Connell, Washington, and was being operated as an aerial application flight under the provisions of Title 14, CFR Part 137, when the accident occurred. The commercial pilot was not injured. Visual meteorological conditions prevailed and no flight plan was filed for the local agricultural flight. During a telephone conversation with the National Transportation Safety Board (NTSB) on August 28, the pilot reported that he was landing on runway 25. The pilot stated that during the landing roll, the airplane encountered a gust of wind and veered to the left. The pilot attempted to regain runway centerline, however, the airplane continued to the left and encountered rough terrain. After encountering the rough terrain, the airplane's right main gear collapsed resulting in substantial damage to the right wing spar and aileron. The pilot reported that the winds, at the time of the accident, were from 190 degrees at 3-5 knots, gusting to 10-15 knots.