What happened
On October 18, 2005, an Aerospatiale AS332L helicopter, registration JA9690, was performing a series of shuttle flights to transport construction materials to the Atobiki Water Bridge in Unazuki, Toyama Prefecture. The mission involved using a 20-meter sling to move scaffolding and aluminum pipes to the bridge for safety inspections.
After successfully completing six deliveries, the aircraft arrived for the seventh load, which consisted of aluminum pipes and ladders weighing approximately 1.1 tons. During the unloading process, the pilot grounded the cargo briefly to stabilize its rotation before lifting it again to reposition it according to instructions relayed from the ground. As the cargo was being displaced, it swung toward the marshaller. The worker's right leg was caught between the moving cargo and an H-beam located on the bridge surface, resulting in a compound fracture of the right lower leg bones. The crew and the aircraft were uninjured.
The investigation
The investigation examined the flight sequence, the movement of the suspended load, and the safety protocols in place at the site. Investigators reviewed the pilot's maneuvers, the mechanic's role in relaying signals, and the physical conditions of the bridge, which was narrow and occupied by previously delivered materials. The inquiry also looked into the company's flight operating procedures and the coordination between the on-site representative, the safety expert, and the ground crew.
Findings
- The movement of the cargo was influenced by the pilot's attempt to reposition the load following signals from the ground.
- The marshaller was walking on the bridge surface near H-beams rather than staying within the designated central passage at the moment of impact.
- The company's flight operating procedures lacked specific instructions regarding safety precautions for marshallers, particularly concerning maintaining stable footholds in confined spaces.
- There was no evidence that a pre-operation safety meeting had been conducted involving the pilot, mechanic, marshaller, and site representatives prior to the day's tasks.
- The specific responsibilities of the on-site safety expert and the site representative were not clearly defined.
The cargo moved toward the marshaller and struck his leg, sandwiching it against an H-beam.