Accident Sequence
During the final approach to landing, the pilot heard a thud. Subsequently, the aircraft entered an uncontrolled left turn. After completing approximately 360 degrees of rotation, it struck the ground in a left-wing-low, nose-low attitude.
Investigation Findings
Examination of the wreckage revealed a failure of the airframe tubing at the lower forward door frame. The failure occurred in an area where a conglomerate weld joined tubing that was part of the door frame, firewall/engine mount, and right forward lift strut support. The tubing had separated before impact. Approximately three-quarters of the fracture surface showed evidence of corrosion, while the remaining portion was due to overload, but not impact-related.
With this structural failure, the leading edge of the right wing would twist upward, and the engine (with power applied) would move up and to the left, contributing to the loss of control.
Related Service Information
Piper Service Bulletin #819, dated February 28, 1986, titled "Fuselage Door Frame Tube Corrosion," addressed the hazard of corrosion in this specific area.