A loose cable aboard the cargo ship Dali was identified as the primary cause of the ship’s critical power failure just minutes before it collided with Baltimore’s Francis Scott Key Bridge, according to a detailed investigation by the National Transportation Safety Board (NTSB). The outage disabled the ship’s propulsion and steering systems, leaving the vessel uncontrollable and directly contributing to a catastrophic bridge collapse that killed six construction workers.
Investigators determined that the power failure originated from a disconnected signal wire in the ship’s secondary transformer and breaker system. The loose wire caused a circuit fault, which tripped breakers and led to a blackout across key ship systems. While the crew was able to restore some power temporarily, a second outage struck, preventing the steering pumps from operating and leaving the ship unable to maneuver.
Eyewitnesses and engineers explained that detecting such loose connections is extremely difficult under normal maintenance procedures. The crew had been following standard protocols, which did not include inspecting individual signal wires for potential disconnections. Experts suggested that modern techniques, such as infrared thermal imaging, could help identify such hazards before they lead to catastrophic failures.
The blackout occurred at a critical moment as the Dali approached the Key Bridge. With both propulsion and steering incapacitated, the ship drifted uncontrollably into a support column. The collision caused a portion of the bridge to collapse, tragically killing workers on site. The NTSB described the accident as preventable, noting that proper maintenance, inspection, and infrastructure safeguards could have averted the tragedy.
Additional factors compounded the situation. The ship’s backup generators failed to start automatically due to a malfunctioning fuel pump, which meant the crew could not quickly regain full power. Investigators highlighted the gaps in both shipboard maintenance procedures and bridge safety assessments. Baltimore authorities had not fully analyzed how vulnerable the Key Bridge was to collisions by large vessels, leaving the infrastructure exposed to catastrophic impacts.
Following the investigation, the NTSB issued recommendations for shipping companies to implement more rigorous wiring inspections and testing protocols to prevent loose connections from causing critical power failures. Authorities were also urged to conduct comprehensive vulnerability assessments for bridges, particularly those spanning busy shipping lanes, to ensure early detection and mitigation of potential hazards.
This incident underscores the devastating consequences of a seemingly small technical failure. A single loose cable triggered a chain reaction that disabled essential ship systems, led to the destruction of critical infrastructure, and resulted in multiple fatalities. Maritime experts warn that rigorous maintenance, enhanced safety protocols, and proactive infrastructure planning are essential to prevent similar disasters in the future.
The Key Bridge collapse serves as a stark reminder that even minor oversights in engineering and maintenance can have catastrophic consequences, emphasizing the need for strict adherence to safety standards in maritime operations and infrastructure management.
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