What happened
The incident occurred while the twin engine aircraft was cruising at an altitude of 9,000 feet under good weather conditions. During this phase of flight, the plane went out of control and entered a steep dive. The aircraft subsequently crashed into a wooded hill situated approximately 22 kilometers northeast of Bozeman. All 10 occupants on board were killed in the accident.
Findings
The investigating board determined that the loss of control was not due to pilot error or mechanical malfunction unrelated to airframe integrity. Instead, the official findings concluded that the crash resulted from a structural failure of the upper vertical fins and rudders. This failure was attributed to flutter, which caused the aircraft to become uncontrollable.