NTSB’s preliminary report on Dali points to blackouts before collision


NTSB preliminary report shows Dali suffered blackouts day before the tragic collision.

The U.S. National Transportation Safety Board (NTSB) has released a preliminary report shedding light on the sequence of events leading up to the allision of the MV Dali with the Francis Scott Key Bridge in Baltimore. The incident, which occurred on March 26, 2024, resulted in a section of the bridge collapsing onto the vessel’s forward deck.

The Singapore-flagged cargo vessel was transiting out of Baltimore Harbor when it experienced a loss of electrical power and propulsion, causing it to strike the southern pier supporting the central truss spans of the Key Bridge.

After entering the Fort McHenry Channel, the vessel experienced another blackout, causing a loss of electrical power to the main engine cooling water pumps and steering gear pumps. Despite efforts to restore power, the vessel lost propulsion and steering, leading to the collision with the Key Bridge.

The crew managed to restore power briefly, but a second blackout occurred just before the collision. Although the emergency generator provided power to some systems, it was insufficient to prevent the accident.

Tragically, the incident claimed the lives of six construction workers who were on the bridge at the time of the incident.

Power loss on the previous day

According to the report, about 10 hours before leaving Baltimore, the Dali experienced a blackout during in-port maintenance. A crew member mistakenly closed an inline engine exhaust damper while working on the diesel engine exhaust scrubber system. This caused the engine to stall, resulting in a loss of power. Although power was temporarily restored, insufficient fuel pressure led to a second blackout.

While recovering from the second blackout, the crew changed the electrical system to use breakers HR1 and LR1 along with transformer TR1, instead of the HR2 and LR2 breakers that had been used for several months. This new configuration, with TR1 and its associated breakers HR1 and LR1, was in place when the ship departed on March 26.

“During both of these electrical power-loss events, the online generators’ breakers (DGR2 and DGR3) to the HV bus opened before the HR2 or LR2 breakers opened. During the recovery, the crew put TR1 online to feed the LV bus because TR2 had reportedly been in use for several months. The first vessel blackout after departure on March 26 occurred when the HR1 and LR1 breakers opened unexpectedly,” the report said.

On March 28, the owner took samples of the low sulphur marine gas oil (LSMGO) being used at the time of the accident, and tests showed no fuel quality issues. Data from the ship’s electronic chart display and information system (ECDIS) and the pilots’ portable pilot unit (PPU) were also downloaded and are still under review.

NTSB continues to focus on the vessel’s electrical configuration and its potential implications on the voyage leading to the accident.

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