Accident Details
A pilot with 9,375 hours of flight experience was providing helicopter rides to attendees of a local festival. Each flight lasted six to seven minutes. On the accident flight, the pilot departed with two passengers and climbed to an altitude of 500 feet above ground level. Shortly after reaching that altitude, the engine began firing through the exhaust and started losing power. The pilot initiated an autorotation and aimed to land in a school playground. While maneuvering toward the playground, the engine stopped producing power entirely.
During the landing, the helicopter slid forward. The skids collapsed, and the main rotor severed the tail boom.
Post-Accident Actions
Before exiting the helicopter, the pilot secured the electrical switches, the magnetos, and turned off the fuel shut-off valve.
Examination Findings
Examination of the engine revealed that when the fuel shut-off valve was later turned on, fuel began to drain from the port where the main fuel line attached to the fuel manifold valve. The b-nut securing the line to the manifold was partially attached to the port and was finger loose. After tightening the b-nut, the engine was test run on the airframe. It started immediately and ran at various power settings without interruption.
Pilot Statement
According to the pilot, he had removed and reassembled the fuel manifold valve approximately nine hours prior to the accident.