On March 21, 2000, at 1500 central standard time, a Cessna A188B, N4859Q, sustained substantial damage when it impacted the terrain during a forced landing following a loss of aileron control during flight. The 14 CFR Part 91 maintenance flight was operating in visual meteorological conditions and was not on a flight plan. The commercial rated pilot received serious injuries. The flight originated from the Mid Continent Airport, Hayti, Missouri about 1450 for a local flight. The airplane had just received an annual inspection and a maintenance test flight was being performed. The pilot reported, in a written statement, that during the flight the aileron control was ineffective. He reported that the "...right aileron appeared to be disconnected, moving up and down, [with] no response." The pilot said that he was in a right turn and was unable to bring up the right wing. He said that he was losing altitude and decided to land the airplane on "... soft plowed ground..." The pilot said that, during the landing, the right wing struck the ground. During a postaccident examination of the aircraft, the right aileron pushrod end bearing bolt was found installed in the bellcrank, but the bolt did not pass through the rod end bearing. According to maintenance records, the aileron pushrod end bearings were replaced during the annual inspection due to excessive play. No other anomalies were found with respect to the aircraft or aircraft systems.