A crewmember’s mistake caused a Singapore-flagged cargo ship to blackout a day before it crashed into the Francis Scott Key Bridge in late March, causing it to collapse, according to a preliminary report from federal investigators. 

The report, from the National Transportation Safety Board (NTSB), determined that a crewmember of the Dali was responsible for accidentally disabling the vessel’s equipment during in-port maintenance while moored at the Seagirt Marine Terminal in Baltimore on March 25.  Crewmembers experienced a second blackout due to insufficient fuel pressure for the online generator. 

It is still unclear what role these earlier technical malfunctions may have played in the vessel’s loss of power before it hit the bridge. 

When the Dali was a little more than half a mile from the bridge in the early hours of March 26, a primary electrical breaker that fed most of the ship's equipment and lighting unexpectedly tripped, causing the ship to lose electrical power and experience another blackout. 

FLORIDA BUS CARRYING FARM WORKER CRASHES, KILLING AT LEAST 8 AND INJURING DOZENS MORE: OFFICIALS

Key Bridge explosives

Explosive charges are detonated to bring down sections of the collapsed Francis Scott Key Bridge resting on the container ship Dali on Monday, May 13, 2024, in Baltimore.  (AP Photo/Mark Schiefelbein)

The main propulsion diesel engine shut down after the pumps lost electrical power. The ship's crew was able to restore power, then called for an assist from tug boats and the senior pilot ordered the ship's anchor to be dropped.

A second blackout then happened, and a marine radio call was made to warn waterborne traffic. The ship then struck a main support pier on the bridge, causing it to collapse within seconds.

The ship, which was headed from Baltimore to Sri Lanka, issued a mayday alert with just enough time for police to stop traffic, but not enough to save the bridge workers who plunged to their deaths. 

52 CONFIRMED DEAD, 20 MISSING AFTER FLASH FLOODS DEVASTATE INDONESIA'S SUMATRA ISLAND

The board launched its investigation almost immediately after the collapse. Investigators boarded the ship to document the scene and collect evidence, including the vessel's data recorder and information from its engine room, according to board chair Jennifer Homendy. Investigators also interviewed the captain and crew members. The FBI has also launched a criminal investigation into the circumstances leading up to the collapse.

Baltimore Francis Scott Key Bridge site

Wreckage of the Francis Scott Key Bridge rests on the container ship Dali, as President Biden takes an aerial tour of the collapsed Francis Scott Key Bridge in Baltimore, Friday, April 5, 2024, as seen from an accompanying aircraft.  (AP Photo/Manuel Balce Ceneta)

Investigators also planned to review policies, training practices and other factors that could be relevant. And the design, engineering and condition of the bridge would be studied, she said.

On Monday, crews conducted a controlled demolition to break down the largest remaining span of the collapsed Francis Scott Key Bridge, a major step in freeing the grounded Dali container ship.

CLICK HERE TO GET THE FOX NEWS APP

A full investigation could take a year or more, the NTSB said. The board's preliminary report likely includes a fraction of the findings that will be presented in its final report.

The Associated Press contributed to this report.