What happened
The owner of an Enstrom helicopter, which was currently outside its annual inspection limitations, decided to fly the aircraft off a trailer. The objective was to reposition it for maintenance prior to a ferry flight. During the initial climb phase, at an altitude of approximately fifty feet, the pilot heard a loud noise. Immediately following this event, the engine speed increased, and the engine became disengaged from the rotor drive system.
The investigation
The pilot executed an autorotation maneuver in an attempt to control the descent. Despite these efforts, the helicopter sustained substantial damage upon impact. The owner stated that he believed the failure was caused by a sprag clutch malfunction.
Findings
The incident occurred during a low-level repositioning flight. The primary mechanical issue involved the disengagement of the engine from the rotor drive system. The pilot's assessment pointed to a specific component failure within the transmission assembly.