BALTIMORE– The power outages the container ship Dali experienced before leaving the Port of Baltimore were “mechanically distinct from” the outages that resulted in the deadly collapse of the Francis Scott Key Bridge hours later, congressional testimony showed Wednesday.
“Two of these related to routine maintenance in the port. Two of these were the unexpected tripping of circuit breakers during the accident trip,” National Transportation Safety Board Jennifer Homendy testified.
The Dali was bound for Sri Lanka, loaded with shipping containers and enough supplies for a month’s journey. Shortly after the ship left the Port of Baltimore early on March 26, it lost power and propulsion and crashed into one of the bridge’s supporting columns, killing six construction workers.
Homendy’s comments came the day after the safety council released its preliminary report on the bridge collapse. Their full investigation could take a year or more.
The ship’s first power outage occurred after a crew member accidentally closed an exhaust muffler during maintenance work in the port, causing one of the diesel engines to shut down, the report said. A backup generator was automatically turned on and continued to run for a short period – until insufficient fuel pressure caused the fuel pressure to come back on, resulting in a second blackout.
While recovering from the power outages, crew members made changes to the ship’s electrical configuration and switched to a different transformer and set of breakers, according to safety investigators.
“Changing breakers is not unusual, but could have impacted operations as early as the next day during the accident trip,” Homendy testified before the U.S. House Committee on Transportation and Infrastructure on Wednesday morning.
She said the board is still gathering more information about the exact cause of the various power outages. The FBI has also launched a criminal investigation into the circumstances that led to the collapse.
When the surf stumbled as the Dali approached the bridge, Homendy said the ship’s emergency generator kicked in. That generator can power the ship’s lights, radio and other functions, but it cannot restore propulsion.
“Without the propeller turning, the rudder was less effective,” Homendy said. “They were basically drifting.”
While there is redundancy built into the ship’s systems, she says it is no different from other ships in terms of emergency generator functions and other factors. She said investigators are working closely with Hyundai, the manufacturer of the Dali’s electrical system, to determine what went wrong after it left the Port of Baltimore.
She also reiterated another finding from the report, which said testing of the ship’s fuel revealed no concerns about its quality.
The safety council launched its investigation almost immediately after the collapse, which left six members of a roadworks crew dead. Investigators boarded the ship to document the scene and collect evidence, including the ship’s data recorder and information from the engine room.
The preliminary report details the chaotic moments leading up to the bridge’s collapse, as crews rushed to resolve a series of electrical faults that cropped up in quick succession as disaster loomed.
At 1:25 a.m. on March 26, when the Dali was just over half a mile from the bridge, the circuit breakers powering most of the ship’s equipment and lighting tripped unexpectedly, causing a power outage. The main propulsion diesel engine automatically shut down after the cooling pumps lost power and the ship lost control.
Crew members were able to temporarily restore electricity by manually closing the faulty circuit breakers, the report said.
The ship was less than a quarter mile from the bridge when it suffered a second power outage due to more broken surf. The crew restored power again, but it was too late to avoid hitting the bridge.
A last-minute emergency call from the ship allowed police to stop traffic, but they did not have enough time to alert a team of construction workers who were patching holes in the bridge. One man was rescued from the water. A road maintenance inspector also survived by running to safety in the moments before the bridge fell.
The last bodies of the six victims were recovered from the underwater wreck last week.
On Monday, crews conducted a controlled demolition to demolish the largest remaining span of the collapsed bridge, which landed draped over the bow of the Dali. The ship is expected to be refloated and returned to the Port of Baltimore early next week, officials said Wednesday.