Summary
On 18 October 2011, at approximately 08:30 local time, a Eurocopter AS 350 B3 helicopter (registration HB-ZES) operated by Eagle Helicopter SA was conducting external load operations at a pick-up area on the road between Bourg-St-Pierre and the Grand-St-Bernard tunnel. The helicopter, piloted by a single pilot, was lifting a pallet weighing 450 kg when the downwash caused a prefabricated facade element to topple. The element struck a worker from the construction company, who was responsible for load sequencing, resulting in serious injuries. The helicopter sustained no damage, but the facade element was damaged.
Accident Details
The construction company had hired Eagle Helicopter SA to transport and place prefabricated elements for an extension of the Valsorey mountain hut. The day before the accident, the elements were deposited at the pick-up area. On the morning of the accident, the worksite was secured with a red vehicle blocking the access road and warning signs. A flight assistant briefed the workers on safety measures and designated a safety perimeter. The injured worker was positioned near the loads to monitor them during lifting, as per instructions.
At 08:05, the pilot departed from Sion with two flight assistants, dropped one at the hut, then proceeded to the pick-up area. After unloading equipment, the helicopter transported five workers to the hut and returned alone. The pilot then prepared to lift a pallet using a 30-meter sling. As the pallet was raised two to three meters above the ground, a flight assistant observed a facade element toppling. The pilot also saw the element fall. The element had been leaning against two others and a mesh fence. Workers rushed to lift the element and found the injured worker underneath. The worker was evacuated by helicopter for medical treatment.
Causes
The accident investigation concluded that the accident was caused by the toppling of a building element due to the downwash of the helicopter, which seriously injured a worker who was in a danger zone. Improper storage of the facade elements contributed to the accident.