Incident Overview
A helicopter was engaged in transporting empty cranberry bins using a cargo hook. The bins were lifted from a flatbed trailer located approximately 4 feet from a ground crewmember, who had nine years of experience in hook-up operations. After the fifth lift, the ground crewmember attempted to run to and assist a truck driver of another trailer. Despite wearing a hard hat equipped with a combination ear muffs/radio receiver and microphone, the crewmember did not advise the pilot of his intentions. He then ran under the track that the helicopter had flown during the previous four lifts.
Sequence of Events
As the helicopter flew over the ground crewmember, the cargo hook opened without any command from the pilot. The bins fell approximately 8 feet and struck the crewmember.
Cargo Hook System Details
The cargo hook system had been removed from another helicopter in 2002. That helicopter had originally had the system installed at a completion center in 1997. The hook release cable installed was Bell part number 206-072-903-101. However, the correct part number was 206-072-903-1, which is approximately one inch longer. The longer cable would have provided sufficient slack to normally preclude any tension on the cargo hook manual release mechanism. After discovering the incorrect part number, the operator found that another of his helicopters was also equipped with the shorter release cable. He subsequently replaced it with the longer cable.