Key Metrics
16.81
Heat Index-
Impact LevelMedium
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Scope LevelNational
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Last Update2025-08-07
Key Impacts
Positive Impacts (1)
Negative Impacts (6)
Event Overview
A critical technological failure in United Airlines' weight and balance system caused widespread operational paralysis, exposing vulnerabilities in aviation infrastructure's dependence on automated systems. The disruption highlights systemic risks in centralized technical architectures and cascading effects on national transportation networks, while emphasizing the sector's ongoing challenges in balancing efficiency with redundancy.
Collect Records
United Airlines Grounds All US Mainline Flights Due to Weight and Balance Computer System Outage
On Wednesday, United Airlines grounded flights nationwide across the United States as a result of a technology issue with its weight and balance computer system, Unimatic. The disruption began at 6:12 p.m. Eastern Time (ET) and lasted for several hours. According to United Airlines, this outage triggered more than 1,000 delays and dozens of cancellations nationwide. The problem was confirmed to be unrelated to recent cybersecurity issues affecting the airline industry, and the specific cause remains undetermined.
A spokesperson from United Airlines stated on Wednesday night: "The underlying technology issue has been resolved and while we expect residual delays, our team is working to restore our normal operations."
The Federal Aviation Administration (FAA) acknowledged the situation, saying: "We’re aware United experienced a technology issue disrupting their operations. Some delays may continue as they work through the recovery process.” The FAA also reported that it was assisting United to address the flight backlog and remained in close contact with the airline.
Passengers across the country, including travelers at Nashville and Denver airports, experienced delays of approximately two hours due to the outage. United offered affected passengers options including hotel accommodations and rebooking on future flights.
By Wednesday night, flights had started to resume boarding in some locations, although not all flights could depart due to ongoing air traffic and recovery efforts. United Airlines stated that its team continued working to restore standard operations and address residual delays resulting from the incident.
Key facts:
- Outage occurred on Wednesday beginning at 6:12 p.m. ET.
- Caused by a technology issue with United’s weight and balance computer system known as Unimatic.
- Over 1,000 United flights delayed and dozens cancelled nationwide.
- FAA and United Airlines collaborated closely to manage disruptions and recovery.
- Issue resolved within several hours, but delays and impact on passengers continued into the night.
- United clarified that the outage was not related to recent cybersecurity events.