NTSB Provides Update on Dali Crash Investigation

The National Transportation Safety Board (NTSB) has released an update regarding its investigation into loss of power on board the containership Dali and its subsequent allision with Baltimore Francis Scott Key Bridge.

The update from NTSB is part of an ongoing investigation and does not contain any conclusions about the cause of the incident.

Preliminary findings released in May revealed that during Dali’s ill-fated departure from the Seagirt Marine Terminal, electrical breakers HR1 and LR1 unexpectedly tripped when the ship was about three lengths away from the Francis Scott Key Bridge. This resulted in a total blackout, affecting the ship’s lighting and most equipment.

While inspecting and testing the ship’s electrical power distribution system, NTSB investigators discovered an interruption in the control circuit for HR1’s undervoltage release, an electrical component designed to open a breaker when voltage drops below certain thresholds.

A terminal block, an insulated block connecting multiple wires, was removed from the control circuit, along with two sections of control wiring. The NTSB Materials Laboratory is currently examining these components.

The investigators are continuing to assess the vessel’s electrical power distribution system and all other aspects of the incident to determine the probable cause and potential safety recommendations.

The incident occurred as the Dali was leaving Baltimore Harbor early on March 26. The vessel lost electrical power and propulsion, striking the southern pier supporting the central truss spans of the Francis Scott Key Bridge, resulting in a portion of the bridge collapsing. Six construction crew members who were on the bridge at the time were fatally injured, one was seriously injured, and one crew member on the Dali was also injured.

The NTSB’s preliminary report released last month revealed the Dali experienced two power blackouts the day before the incident. The first was caused by a crew member mistakenly blocking the generator’s exhaust gas stack. The crew manually restored power and switched the bus configuration to use different breakers (HR1 and LR1) and transformers. The second was due to insufficient fuel pressure. The NTSB said the first blackout after the ship’s departure was due to unexpected tripping of the breakers HR1 and LR1.

The NTSB is looking into the electrical configuration and its potential impacts on the accident voyage.

The Dali on Monday now departed Baltimore for the first time since the incident. The NTSB investigators have completed in-person interviews with the vessel’s crew, conducted onboard examinations of the engineering systems, and tested the electrical systems. Documentation of the vessel’s structural damage is still in progress.

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