What happened
While the helicopter was positioned on the landing pad, the pilot advanced the fuel control lever. This action caused the engine to rev and increase power significantly. The resulting surge in power reached a level where the pilot was unable to control the aircraft as it began bouncing on the pad.
The investigation
An examination of the helicopter's airframe was conducted, which revealed no discrepancies that would have prevented the normal operation of the flight or engine controls. Additionally, a test cell run of the engine was performed, and no issues were found regarding its operation across various power settings.
Findings
According to the manufacturer, moving the fuel control lever beyond the "Flight" detent causes the emergency valve to progressively open to supply the engine. The investigation concluded that the pilot's incorrect operation of the fuel lever may have contributed to the over-revving of the engine.