Loose wire led to power outage before US ship crash

A loose cable caused a power outage on the 1,000-foot cargo ship Dali, which led to the ship colliding with Baltimore’s Francis Scott Key Bridge, killing six construction workers and destroying the span.

A National Transportation Safety Board investigation found that a single loose wire in the electrical system caused the breaker to trip unexpectedly, setting off a series of events that led to a power outage and loss of propulsion and steering for two ships.

In its final conclusions on the cause of the crash in March 2024, the NTSB said wire tag taping prevented proper insertion of the wire and caused inadequate connection.

NTSB Chairman Jennifer Homendy likened the grueling search for the wire to finding a single loose rivet on the Eiffel Tower.

The NTSB and shipbuilder HD Hyundai Heavy had to test thousands of cables to find the problem, he added.

“It’s like looking for a needle in a haystack.”

The board also said a lack of countermeasures that would have reduced the bridge’s vulnerability to impacts from ocean-going vessels, which could have been implemented if a vulnerability assessment had been conducted by the Maryland Transportation Authority, also contributed to the collapse.

Board staff said they advised operators to complete periodic inspections of high voltage switchboards and suggested changes that would allow ships to recover from power loss more quickly.

HD Hyundai said in a statement that it delivered a safe, seaworthy ship with automated systems and critical backups to quickly respond to power outages in 2015, but “unfortunately, the ship owner and operator circumvented these safety measures.”

The company added that there was “no indication that any wires were loose” when it delivered the ship, and said that “if any wires become loose due to vibration or other cause within ten years, the owner and operator should detect this through a routine inspection and normal maintenance.”