BALTIMORE — The National Transportation Safety Board has released its preliminary investigative report into the Key Bridge collapse.
Investigators concluded the DALI ship experienced two power blackouts within a couple minutes before it crashed into the bridge.
The report details a harrowing four minutes endured by the crew aboard, including a senior pilot and apprentice.
According to the investigation, the vessel first lost electrical power at 1:25 in the morning, just over half-a-mile (approximately three ship lengths) away from the bridge.
Specifically, two electrical breakers responsible for feeding most of the ship’s equipment and lighting, failed.
This caused the DALI's main engine to shut down along with the cooling water and steering gear pumps.
As result, the ship's propeller stopped leaving the rudder inoperable.
This triggered two emergency generators to take over the power supply.
Crew members were able to get main power restored, only for a second blackout to occur 0.2 miles from the bridge.
This time another pair of breakers tripped, prompting the generator to kick in again.
Despite closing off the breakers and regaining power, the propeller never got back working before the collision.
Between all the panic, the ship pilot was busy calling for tugs to assist and for anchors to be dropped.
Although help was on the way, it was too late.
RELATED: Ship collides with Francis Scott Key Bridge causing collapse
Meanwhile, a crew member in the process of releasing the brake on the port anchor had to escape to avoid being hit by falling bridge debris. Investigators are still reviewing how much anchor chain was rolled out.
The collapse caused seven construction workers to fall into the water below, killing six of them.
Since the collision, investigators have dug more into the DALI's condition prior to setting sail from the Port of Baltimore.
About 10 hours before departing, the report reveals how the ship experienced two blackouts while undergoing maintenance.
The report says a crew member "mistakenly closed an inline engine exhaust damper."
Investigators say this "effectively blocked the engine’s cylinder exhaust gases from traveling up its stack and out of the vessel, causing the engine to stall."
Although the crew got power back, the ship had insufficient fuel pressure causing a decrease in speed, ultimately leading to more breaker issues and a second outage.
At this point the crew decided to switch breakers since they'd been heavily used over the last several months. It was those breakers that got switched out that failed leading up to the crash.
Following the crash all crew members tested negative for drugs and alcohol.
There were also no problems identified with the quality of fuel used by the ship.
MORE: Maryland: After the Key Bridge Collapse
WMAR-2 News previously reported in depth on the history of the DALI.
It passed U.S. Coast Guard inspection as recently as September 2023, but has two past documented incidents.
The most recent being June 2023, when a faulty monitor gauge for fuel pressure was fixed before departing San Antonio, Chile.
The second incident happened in July 2016, when the DALI scraped a pier at the Antwerp Terminal in Belgium, damaging its hull and leaving it temporarily disabled.
On Monday officials detonated the bridge wreckage that remained atop the DALI, enabling the ship to be removed.
It could take years for investigators to fully determine the official probable cause of the collision.
The State estimates a new bridge costing between $1.7 and $1.9 billion, with an approximate completion date of Fall 2028.
To read the NTSB preliminary report, click here.
