BALTIMORE (AP) 鈥� The electrical blackouts experienced by the container ship Dali before it left Baltimore鈥檚 port were 鈥渕echanically distinct from鈥� those that resulted in the deadly collapse of the Francis Scott Key Bridge hours later, according to congressional testimony Wednesday.
鈥淭wo were related to routine maintenance in port. Two were unexpected tripping of circuit breakers on the accident voyage,鈥� National Transportation Safety Board Jennifer Homendy testified.
The Dali was headed to Sri Lanka, laden with shipping containers and enough supplies for a monthlong voyage. Shortly after leaving the Port of Baltimore early on March 26, the ship lost power and propulsion and crashed into one of the bridge鈥檚 supporting columns, killing six construction workers.
Homendy鈥檚 remarks came the day after the safety board released its preliminary report into the bridge collapse. Their full investigation could take a year or more.
The ship鈥檚 first power outage occurred after a crew member mistakenly closed an exhaust damper while conducting maintenance in port, causing one of its diesel engines to stall, according to the report. A backup generator automatically came on and continued to run for a short period 鈥� until insufficient fuel pressure caused it to kick off again, resulting in a second blackout.
While recovering from those power outages, crew members made changes to the ship鈥檚 electrical configuration, switching to a different transformer and set of breakers, according to safety investigators.
鈥淪witching breakers is not unusual, but may have affected operations the very next day on the accident voyage,鈥� Homendy testified Wednesday morning before the U.S. House Committee on Transportation and Infrastructure.
She said the board is still gathering more information about what exactly caused the various power outages. The FBI has also launched a criminal investigation into the circumstances leading up to the collapse.
When the breakers tripped as the Dali approached the bridge, Homendy said the ship鈥檚 emergency generator kicked on. That generator can power the ship鈥檚 lights, radio and other operations, but it can鈥檛 restore propulsion.
鈥淲ithout the propeller turning, the rudder was less effective,鈥� Homendy said. 鈥淭hey were essentially drifting.鈥�
While there is redundancy built into the ship鈥檚 systems, she said it鈥檚 not unlike other vessels in terms of the functions of its emergency generator and other factors. She said investigators are working closely with Hyundai, the manufacturer of the Dali鈥檚 electrical system, to pinpoint what went wrong after it left the Port of Baltimore.
鈥淲e are still on scene and evaluating everything about this accident,鈥� Homendy said.
She also reiterated another finding from the report, which said testing of the ship鈥檚 fuel revealed no concerns about its quality.
The safety board launched its investigation almost immediately after the collapse, which sent six members of a roadwork crew plunging to their deaths. Investigators boarded the ship to document the scene and collect evidence, including the vessel鈥檚 data recorder and information from its engine room.
The preliminary report details the chaotic moments prior to the bridge collapse while crew members scrambled to address a series of electrical failures that came in quick succession as disaster loomed.
At 1:25 a.m. on March 26, when the Dali was a little over half a mile away from the bridge, electrical breakers that fed most of the ship鈥檚 equipment and lighting unexpectedly tripped, causing a power loss. The main propulsion diesel engine automatically shut down after its cooling pumps lost power, and the ship lost steering.
Crew members were able to momentarily restore electricity by manually closing the tripped breakers, the report says.
The ship was less than a quarter of a mile from the bridge when it experienced a second power blackout because of more tripped breakers. The crew again restored power, but it was too late to avoid striking the bridge.
A last-minute mayday call from the ship allowed police to stop traffic, but they didn鈥檛 have enough time to warn a team of construction workers who were filling potholes on 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 of the six victims鈥� bodies was recovered from the underwater wreckage last week.
On Monday, crews conducted a controlled demolition to break down the largest remaining span of the collapsed bridge, which landed draped across the Dali鈥檚 bow. The ship is expected to be refloated and guided back to the Port of Baltimore early next week, officials said Wednesday.
