What happened
The aircraft experienced a crash during a relatively high-speed descent. At the time of the incident, the helicopter had been circling at an altitude of approximately 600 feet above mean sea level while awaiting clearance to land. The pilot in command, seated in the left seat, was not actively flying the aircraft when the event occurred.
The pilot reported feeling no yaw or change in sound prior to the impact. He recalled suddenly observing low rotor RPM before the ground rapidly approached. His next memory was of lying on his back in pain after the crash. Neither the engine nor the rotors were operating at the moment of impact, a fact confirmed by the examination of the wreckage.
The investigation
A thorough mechanical inspection was conducted to determine the state of the aircraft prior to the collision with the ground. Investigators examined the engine and all associated accessories to verify their operational status before the crash occurred.
The analysis revealed that the engine and all of its accessories were capable of normal operation prior to ground impact. This finding indicates that a mechanical failure of the powerplant or its immediate systems was not the cause of the descent.