BALTIMORE — Researchers Try to Determine Cause of Baltimore’s Francis Scott Key Bridge collapse discovered a loose cable that could have caused electrical problems on the Dali, the massive cargo ship that lost power and disastrously veered off course before hitting the bridge.
When the problematic cable was disconnected, it caused a power outage on the ship, similar to what happened as it approached the bridge on March 26, according to new documents released Wednesday by the National Transportation Safety Board.
The documents do not contain any analyses or conclusions, which will be released later in the council’s final report. A council spokesman declined to comment, as the investigation is ongoing.
The Dali was leaving Baltimore for Sri Lanka when its controls failed due to loss of power. It crashed into one of the bridge’s support pillars, destroying the 1.6-mile span and six dead members of a roadworks crew.
Security researchers published a preliminary report earlier this year detailing a series of power problems on the ship before and after it left Baltimore. But the new data provides more detail about how the electrical system may have failed in the critical moments leading up to the deadly disaster.
The Dali first experienced a power failure while it was still in Baltimore. That was after a crew member accidentally closed an exhaust valve while performing maintenance, causing one of the ship’s diesel engines to shut down, the earlier report said. Crew members then made changes to the ship’s electrical configuration, switching from one transformer and fuse system — which had been in use for several months — to a second that was active when the ship departed.
According to investigative reports, investigators found the loose cable in the second transformer and fuse system.
Investigators also removed an electrical component from the same system for additional testing, according to a supplemental report released in June. They removed what’s called a terminal block, which is used to connect electrical wires.
Engineers at Hyundai, the manufacturer of the ship’s electrical system, said the loose cable could create an open circuit and trip a circuit breaker, according to a 41-page report detailing tests conducted on the Dali in the weeks after the collapse. Engineers disconnected the cable as part of a simulation, resulting in a blackout on the ship.
Hyundai sent engineers from its headquarters in South Korea in April to assist with the investigation.
The new documents also include several certificates issued following inspections of the Dali regarding the general condition of the vessel and compliance with maritime safety regulations.
“It’s pretty clear that they think they’ve found a problem that could cause a blackout,” said Tom Roth-Roffy, a former National Transportation Safety Board investigator who focused on maritime investigations. He said the loose cable was at a critical point in the electrical system.
He also noted that investigators clearly took a thorough approach and documented their findings well. The new documents suggest that they found very few other problems as they searched the various systems and machinery aboard the Dali.
As for whether the loose connection points to inadequate maintenance on the ship or other crew issues, Roth-Roffy said it appears to be a toss-up. Checking hundreds or thousands of wires is a tedious and time-consuming process, he said, and there are numerous factors that can cause connections to loosen over time, including the constant vibrations on a ship.
“To say that this should have been discovered is probably true, but somewhat unrealistic,” he said. “But the ship’s crew is ultimately responsible for the proper maintenance and operation of the ship.”
The Dali left Baltimore for Virginia in late June. It was to undergo repairs there and local media reported last week that it will sail to China, probably sometime later this month.
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Associated Press editor Ben Finley contributed to this report.