What happened
The incident occurred during a private flight conducted for pilot recurrency purposes. The instructor pilot initiated a simulated engine failure while the helicopter was climbing at approximately 100 feet above ground level (AGL). In response, the pilot executed an autorotation maneuver. As the aircraft descended to roughly 50 feet AGL, the rate of descent increased. The pilot rolled in the throttle in an attempt to arrest the descent and recover power.
According to the check pilot, the engine failed to respond to the throttle input. Consequently, a flare was initiated in an effort to slow the helicopter's forward and downward momentum. Despite these efforts, the helicopter subsequently impacted the terrain in a tail-low attitude and rolled over. The private pilot noted that he and the instructor had successfully performed three prior simulated engine failures shortly before this event, executing powered recoveries to a hover after each previous maneuver.
The investigation
A physical examination of the helicopter was conducted to determine if mechanical issues contributed to the accident. The inspection revealed no evidence of pre-existing mechanical malfunction or failure. Furthermore, the fuel-injected engine was able to start and run normally after three to four start attempts. It also responded to throttle inputs in a normal manner during post-accident testing.
Findings
The sequence of events indicates that the accident resulted from the pilot's inability to successfully recover from the simulated engine failure at low altitude. The prior successful maneuvers suggest that the issue was not related to the aircraft's mechanical reliability, as confirmed by the examination which showed the engine functioned normally after the incident.