Incident Overview
An airplane was on final approach to a 4,448-foot-long runway with a displaced threshold of 740 feet. The aircraft was observed to pitch down more than 60 degrees in a turn before impacting a grass knoll located approximately 300 feet from the displaced threshold. The airplane came to rest inverted.
Witness Accounts
A passenger in a landing helicopter reported observing the aircraft from a position about one-third down the runway and as far left as possible in the taxiway area, finishing the final approach. The helicopter was at 15 to 20 feet altitude. The passenger stated that the airplane's wings began to seesaw left and right, back and forth, and then the airplane dropped sharply. Debris was observed flying up from below the drop-off at the end of the runway. Another witness saw the airplane pitched down more than 60 degrees while turning.
Investigation Findings
Examination of the wreckage did not reveal any pre-impact malfunctions of the airframe or engine.