What happened
On July 21, 2009, at 10:10 Pacific daylight time, a fatal accident occurred near Willow Creek, California, during a proficiency rappel training operation. The flight involved a Bell 212 helicopter, registration N212HP, operating under contract to the USDA Forest Service by Heli-1 Corporation. The mission was being conducted under visual flight rules (VFR) in visual meteorological conditions with 10 miles of visibility.
Prior to the accident, a pre-operation equipment check was performed. During this check, a broken "Kong" clip was identified on the interface between the Tri-link and the J-hook on the harness of one rappeller. This clip was replaced with an authorized substitute, a rubber O-ring.
Approximately six minutes later, while the helicopter was in a stabilized hover at an altitude of 225 to 250 feet, the rappeller transitioned to the port side skid. Witnesses on the ground observed the individual fall down the rope at an excessive speed. The airline transport pilot, the spotter, and the three other crew members were not injured.
The investigation
Investigators from the US Forest Service examined the rope and harness assembly following the accident. While the J-hook remained attached to the Sky Genie descent control device, the J-hook was not mechanically attached to the Tri-link and harness. A broken O-ring was recovered on the ground approximately 30 feet from the harness assembly; investigators believe this was the O-ring used to center the hardware.
An examination of the J-hook, Sky Genie, Tri-link, and harness showed no mechanical defects or malfunctions. The investigation determined that the Tri-link and J-hook were not mechanically linked before the rappeller exited the aircraft, but were instead held in place only by the non-load-bearing rubber O-ring.