On December 13, 1995, at 1620 central standard time, a Grumman G- 164B, N6642K, was substantially damaged upon impact with terrain while maneuvering near Pawnee, Oklahoma. The commercial pilot was not injured. The airplane was been operated by Cassody Flying Service as an aerial application flight under Title 14 CFR Part 137 when the accident occurred. Visual meteorological conditions prevailed for the flight for which a flight plan was not filed. According to the operator, the right main landing gear impacted a berm during a spraying run. The landing gear separated from the airframe and the pilot attempted to land in an open field to the north. The pilot was unable to control the airplane while landing with only one landing gear and control was lost during the landing roll. The airplane nosed over, coming to rest in the inverted position. All four wings sustained structural damage and the engine mount was deformed.