Loose Cable Found During NTSB Dali Investigation Could Cause Blackouts
Without comment, the NTSB posted a 41-page document summarizing the findings of the Engineering Group formed to inspect the systems aboard the containership Dali which blacked out in March and destroyed Baltimore’s Francis Scott Key bridge. The report lists a few minor issues while also showing a loose cable found in the breaker system when tested in a simulation caused a brief blackout.
The NTSB notes that initial troubleshooting led to the Engineering Group narrowing its focus on the vessel’s electrical switchgear. The tests detailed in the report took place during April in four separate examination sessions.
The check of the wiring on the transformer and a relay found a “cable was loosely connected,” a condition which representatives from Hyundai informed could create an open circuit and interrupt the 110VDC power on the HV side of the board. According to the report, the engineers said it would trigger an under voltage release trip which would result in a 440V blackout.
After explaining the situation to the NTSB and the other participants, Hyundai conducted a simulation. When the engineers disconnected the cable, all the equipment powered by the Low Voltage (440V) Switchboard blacked out. These included lights throughout the vessel. The report says the system recovered making an automatic transfer and regained power after approximately 10 seconds.
Diagram on the position of the cable from NTSB report
The other items listed in the report (download link) were judged to be non-consequential. Most of the systems are listed to be operating correctly.
The inspection and testing were conducted by a team of experts including representatives from the vessel’s owners Grace Ocean and operators Synergy Marine. HD Hyundai which built the vessel in 2015 participated in the four examinations in April along with ClassNK as the vessel’s class society and the Maritime & Port Authority of Singapore as the flag state.
No further analysis was provided on the results of the tests and the NTSB declined comment. Its teams are continuing their analysis. They are not expected to release a report until up to a year after the incident.
The posting of this data came as the Department of Justice had informed the court involved in the claims that it was also conducting investigations aboard the vessel. No further updates have been provided to the court on the status of the inspections, but they were expected to be completed this week.
Tentatively, the Dali was expected to depart Norfolk, Virginia on or about September 17 bound for China. The offloading of containers was completed last month, and the vessel is expected to proceed to a shipyard for repairs.
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