Pampero - Sablons english summary

On 18 February 2020, at around 12:30 a.m., the tanker PAMPERO, travelling up the Rhône, was moored in the lock chamber of the Sablons lock. The lock’s downstream gate consists of four caissons stacked on top of each other. When the lock chamber was two-thirds full, one or two of the intermediate caissons in the gate gave way. The lock chamber suddenly empties. The ship was dragged aft and then thrown out of the lock. The master and deckhand managed to evacuate the wheelhouse before it was torn off by hitting the top of the structure. The upper part of the door was swept away with the vessel and remained embedded in the stern. The boat eventually stabilised. The crew managed to secure it and then, due to gas leaks, evacuated it and jumped to shore.
The crisis management was particularly complex due to the state of the boat and the product transported, vinyl chloride being a toxic and highly flammable gas. The material toll was high : the boat could not be repaired, the lock gate was destroyed and river traffic was stopped for six weeks. The five members of the crew were very shocked by the accident and suffered some physical pain.
The lock is part of a hydroelectric scheme comprising a factory-lock block, a retaining dam and an embankment of the Rhône. It is remote-controlled and automated. Its downstream gate, with lateral movement, is made up of 4 caissons assembled together. It is suspended from a manoeuvring carriage, located 6 m higher, which is connected to a winch and moves on horizontal rails.

The direct causes of the accident were a loss of coupling between the positions of the trolley and the door, due to a blockage on the door at the end of the closing manoeuvre, which was made possible by the non-functioning of the mechanical overload protection of the winch. The trolley was thus able to reach its nominal position, without the door, and activate the sensors used in the automatic systems. The blockage could be related to driftwood.

The other elements that could have contributed to ensuring protection against such a configuration, such as control of the gate’s operating time and current limitation at the variable speed drive, were not set up with safety in mind. More generally, it appears that the analysis of the risks associated with gate failures had not been carried out in sufficient depth in the context of the hazard study associated with the hydraulic structure.
The survey highlights the need to strengthen maintenance at the gates of this lock. It underlines that locks are not currently covered by the regulations on the safety of transport infrastructures and that their consideration in the implementation of the safety policy for hydraulic structures would benefit from being reinforced, not forgetting the fact that lock gates also fall within the scope of the European directive on the safety of machinery.

It led the BEA-TT to formulate recommendations and invitations on these aspects and to seek preventive orientations in connection with the management of driftwood in the vicinity of locks as well as on the processes of remote control operators.