Accident Overview
A commercial pilot and a pilot-rated passenger were conducting a 1,620-nautical mile cross-country flight in a helicopter that had recently been purchased. After a fuel stop, they had traveled approximately 180 miles when the helicopter's main rotor and rotor hub assembly separated from the upper mast. The helicopter then entered an uncontrolled descent and impacted the ground. No eyewitnesses were present at the accident site.
Examination Findings
Post-accident examination of the main rotor mast fracture surfaces revealed signatures consistent with mast bumping. Although evidence of a mast bumping event was identified, the initiating event remains unknown. Examination of the wreckage disclosed no anomalies that would have prevented normal system operation. The engine displayed evidence of rotation at the time of ground impact. Additionally, the cockpit exhibited damage consistent with main rotor contact.
Weather Conditions
On the day of the accident, the outer bands of a tropical storm were making landfall on the Louisiana coast. However, automated weather observing systems located inland near the accident site were reporting visual meteorological conditions at the time of the accident.