The airplane was landing on runway 36, a 2,590-foot-long; 70-foot-wide, turf runway. The pilot stated that the airplane "became uncontrollable" during the landing roll out. The airplane subsequently "drifted" off the left side of the runway, struck a tree, and came to rest in a ditch. The pilot further stated that the runway was "watery and soft." Examination of the wreckage by a Federal Aviation Administration inspector did not reveal any mechanical failures or malfunctions. The airplane sustained substantial damage to both wings. The nearest weather reporting facility, located approximately 25 nautical miles north of the accident location, reported winds from 140 degrees at 10 knots, about the time of the accident.