Agustawestland Spa AW109SP N361CR accident near Astoria, Oregon

Probable cause

The decision by the ship pilot and the helicopter crew to lower the ship pilot to a location on the ship that did not provide the helicopter pilot with an adequate view of the ship. Contributing to the accident was the inadequate pre-mission coordination between the ship, the ship pilot agency, and the helicopter operator.

NTSB analysis

The foreign-registered container ship was inbound to port, and the helicopter was delivering a ship pilot to the ship. Per normal procedures, the helicopter's crew planned to lower the ship pilot to the ship's deck via a cable hoist while the ship was underway. When the helicopter arrived at the ship, dark night conditions prevailed, rain was falling, and the relative wind was blowing onto the starboard (right) bow of the ship. The helicopter crew circled the ship to locate a suitable location to lower the ship pilot and settled upon a location close to the starboard bow. The ship pilot and the helicopter crew agreed that this was the best available location for the transfer. However, this location allowed the helicopter's pilot to see and use only a very small portion of the ship as a visual reference for maintaining the helicopter's position while lowering the ship pilot. Just as the ship pilot made contact with the deck, the ship's bow pitched down, and the helicopter pilot lost visual contact with the ship. Because the helicopter pilot was unable to see the ship, the helicopter began to move aft relative to the ship. The hoist operator was unable to release the hoist cable quickly enough to prevent pulling the ship pilot off the deck and had to cut the cable. The ship pilot fell a few feet to the deck and fractured his scapula.

Ship pilots can be transferred to ships that are underway either by boat or helicopter. The transfer mode determination is made by the ship pilot agency and is typically not made until shortly before the transfer. In this case, neither the ship pilot nor the helicopter crew had complete and accurate knowledge of the ship's deck configuration, particularly with regard to the availability of a suitable location for the transfer, until they arrived at the ship. If a location had been available that would have afforded the helicopter pilot a more encompassing view of the ship, the likelihood of this accident would have been reduced because the helicopter pilot would likely not have lost his visual reference, which would have minimized or eliminated the resulting relative motion between the ship and the helicopter.

The ship pilot agency published procedural guidance for ship operators on helicopter transfers, but that guidance contained only minimal information regarding deck configuration or location requirements for the transfer. There were no published requirements or guidance for the ship to provide information about its deck configuration and accommodations for a helicopter transfer to the ship pilot agency. The establishment of procedures and practices that require more complete advance notice and pre-coordination of any helicopter transfer arrangements could ensure a higher level of operational safety. Subsequent to the accident, the state's ship pilot board recommended better pre-coordination between ship crews and helicopter operators for any planned ship pilot transfers by helicopter.

Text from the NTSB. Open the NTSB docket for WPR14LA160 for the full record.