What happened
Shortly after takeoff from the summit of Pikes Peak, the helicopter's engine lost power. In response to the loss of power, the pilot performed an autorotation straight ahead. During this maneuver, the aircraft collided with trees and subsequently rolled over.
The investigation
Post-accident testing of the Fuel Control Unit (FCU) demonstrated that the unit was unable to achieve the target fuel flow. Analysis of fuel samples revealed visible contaminants, which included filter material as well as particles of glass, sand, plastic, and metal. The metallic components were identified as copper, iron, nickel, and chromium.
Upon disassembly of the FCU, investigators found a clogged amplifier piston filter, a scored isochronous piston, and a collapsed temperature compensator. The engine manufacturer stated that these fuel contaminants are capable of disrupting FCU operation, noting that the scored piston served as evidence of operation with polluted fuel. While the specific source of the contaminants was not determined, no other reports of fuel contamination were found from pilots using the same fuel vendor.