What happened
The airplane was located approximately three-quarters of a mile from the approach end of the runway. At that moment, its wings were rolled 90 degrees from the horizontal position. The nose subsequently dropped, causing the aircraft to descend vertically.
After this initial drop, the airplane appeared to recover and climb briefly. It then banked swiftly to the left before rolling completely inverted. The aircraft impacted the ground while in this inverted attitude.
The investigation
A physical examination of the roll servo was conducted to determine the state of the flight control systems at the time of the accident. This inspection revealed that the autopilot system was engaged when the impact occurred. Additionally, the autopilot control panel was found to be destroyed.