Pilot Report
According to the pilot in command, a hardover occurred in the single-axis autopilot, causing the aircraft to constantly turn right. Due to the continuous bank, the pilot elected to make a precautionary landing in a lake rather than on land.
Aircraft Impact
The aircraft impacted in a lake to the left of the planned course.
Roll Servo Design
The roll servo was designed so that when power was removed from the servo, a spring disengaged the servo from the aileron bridle cable. After recovery of the aircraft from the lake, the spring was found functional.
Witness Observations
Witnesses reported seeing the aircraft flying approximately 10 to 15 feet above the lake surface for about one quarter of a mile. As the aircraft approached a bridge, it pulled up abruptly, stalled, and impacted the water.