Pra Loup english summary

The incident was with the Costebelle gondola located in the Pra Loup ski resort, in Uvernet-Fours in the Alps of the Haute-Provence.
On Sunday 25 March 2018 at 1:33 pm, cabin 7 of the Costebelle gondola fell a dozen metres shortly after leaving the lower station. It hurtled slowly down the slope before stopping at the nets below. The cabin was empty, and there were no casualties. The system came to a standstill after the emergency stop push-button was actuated by the driver, who was informed of the fall of the cabin by radio.
A user evacuation plan was implemented at 3:35 pm : 62 people on the ascent and 10 on the descent were counted. They were rescued up to 4:55 pm.
Finally, the operators stopped operating the gondola, and a prefectural order was issued on 12 April 2018 to suspend operating the system.

The initiating event for the cabin falling is failure of the cabin’s attachment to the cable.
This coupling could not be done when passing the hitch over the clutch ramp at the station, due to a lateral shift of the cable in the clutch area. This was caused by the displacement of the pylon at the exit from the station. The clutch system has been shown to be very sensitive to this displacement.
The non-coupling safety device, which is placed at the clutch area outlet, did stop the system, but the operators’ actions led to poor diagnosis of the situation, and they restarted the gondola without identifying the cause or making a correction.

Organisational and human factors involved were, in particular :
• it was usual to have many alarms triggered which had no purpose ;
• lack of awareness of the risks, linked to the lack of reminders of essential safety points in training in order to reinforce knowledge and skills ;
• a lack of suitable tools to identify causes of a shut-down and instructions to assist in diagnosis ;
• the driver placed too much confidence in the lookout’s diagnosis, and did not warn the technician about this type of alarm.

BEA-TT issued three recommendations and three invitations in the following areas :
• the stability of the pylons with “full excavation” foundations located in front of the teleport stations (upstream and downstream) ;
• the end-of-life issue with old technologies, in particular the “S” type coupling clamps on the Costebelle gondola ;
• operator emphasis on safety management ;
• the wording of the PLC safety alarm messages, and how long the recordings were kept ;
• formalisation of the actions to be implemented following a safety trigger ;
• and passenger evacuation training.