What happened
On December 30, 2010, a Piper PA-46-310P, registration N9103N, crashed in Milaca, Minnesota, while operating under instrument flight rules. The flight had departed from Aitkin Municipal Airport (AIT) and was en route to Beaumont Municipal Airport (BMT) in Texas.
While climbing through 16,800 feet, the aircraft entered a descending right turn, followed by a 360-degree left turn. During this period, the pilot notified air traffic control that the autopilot had disconnected and that the aircraft was in an unusual attitude. The pilot's final communication to the controller stated he was busy attempting to recover the airplane. Radar contact was lost shortly thereafter, and the aircraft subsequently struck the terrain. The crash resulted in 2 fatal injuries.
The investigation
Engine and propeller examinations revealed no mechanical failures that would have prevented normal operation. The engine showed no anomalies, and all cylinders showed compression. The propeller blades were found to be damaged by the impact.
Investigators examined the King KFC-150 series automatic flight control system. Inside the pitch servo housing, a loose screw was discovered. This screw was one of two intended to secure a high wattage resistor to the solenoid housing. While the screw showed signs of corrosion, there was no evidence of electrical arcing or mechanical damage that would have prevented the system from functioning. The operational impact of this loose screw remains unknown.
Toxicology results from the pilot showed the presence of ethanol, though investigators could not determine if this was from ingestion or postmortem production. However, the presence of diphenhydramine, an over-the-counter sedating antihistamine, was found at levels above therapeutic levels.