NTSB investigators said Tuesday that a loose signal wire prompted a container ship to lose low-voltage power before it crashed into and collapsed Baltimore’s Francis Scott Key Bridge last year.
At the board’s meeting to determine probable causes of the incident, Todd Gianelloni, a marine casualty investigator at the NTSB, said staff found that “the initial March 26 low voltage blackout was caused by wire one electrically disconnecting from terminal block 381 with the HP switchboard.”
Previously, investigators believed that the loose signal wire could have played a role in electrical problems on the ship prior to the crash. The Dali ship lost power twice in the minutes before the crash.
Gianelloni said while the vessel operator required crew to investigate the switchboard “periodically,” work instructions did not include “practical guidance” for investigating the individual signal wire. He added that checking each of thousands of signal wires by hand would be “extremely labor intensive” and “operationally challenging,” recommending instead infrared thermal imaging for future inspections.
