A new report says human error is to blame for the meltdown of an electric drive motor last November aboard the Washington State Ferry Walla Walla that disabled the vessel.
The findings, issued Monday, say the Nov. 4, 2012 failure was avoidable and the fault of numerous mistakes made by crew members doing routine annual maintenance at the ferry system’s Bainbridge Island maintenance facility.
The report also says repair costs will total nearly $3 million, far more than the original $300,000 estimates.
According to the report, crew members did not understand the complex work they were doing, which is rarely performed at the Eagle Harbor facility on the 188-car Jumbo-class ferry. There were no written procedures or checklists for the work, and crew members improperly prepared electrical equipment for the maintenance procedure.
Investigators also faulted poor communications between maintenance staff and the Walla Walla’s engine crew.
“We conducted a thorough and detailed investigation into what happened and why,” said David Moseley, Washington State Department of Transportation assistant secretary, ferries division, in a statement. “Safety is our number-one priority at WSF. We need to learn from these mistakes and focus on improving complex maintenance practices.”
WSF is taking a number of steps based on investigator recommendations to prevent similar accidents, including increased training and establishment of new checklists and procedures.
According to the report, two separate crews thought the other had taken protective steps to contain the electrical current that surged into the motor, melting vital parts over a 40 minute period.
No one was injured in the incident.
WSF hopes to return the Walla Walla to service in April following extensive testing and sea trials.