Incident Overview
While flying at 2,300 feet, the pilot disengaged the autopilot. Immediately after disengagement, the pilot could not maintain pitch control, and the airplane entered a series of uncontrollable gyrations. Attempts to regain control were unsuccessful. The airplane subsequently collided with trees approximately five miles west of Baxley Municipal Airport.
Post-Accident Examination
A functional examination of the autopilot assembly after the accident revealed that when the unit was engaged, the pitch servo would only correct the pitch attitude in one direction. Internal examination of the pitch servo disclosed that three transistors had been replaced, and one transistor appeared to be original to the unit. Additionally, a functional check of the pitch trim servo solenoid showed that the unit was not within design specifications.
Pilot Operating Handbook Guidance
According to the pilot operating handbook, if the autopilot is disengaged when opposing mistrim forces are encountered, the pilot may be required to exert control forces in excess of 50 pounds to maintain airplane attitude. The handbook notes that the pilot must maintain this control force while manually retrimming the airplane.