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NATS software defect caused major UK air traffic disruption
A preliminary investigation by National Air Traffic Services (NATS) has identified a software defect as the cause of the major air traffic disruption in the United Kingdom on September 8. The error, which occurred in a millisecond, was triggered during the processing of a manual aircraft code request when the system received a higher-priority message. This caused a failure in the National Airspace System (NAS) that corrupted flight data.
The outage led to more than 2,000 flight cancellations and affected hundreds of thousands of passengers across major airports, including Heathrow, Gatwick, Manchester, and Edinburgh. The disruption lasted several days as the backlog cleared.
NATS CEO Martin Rolfe clarified that the incident was not caused by military intervention, a cyberattack, or related to previous technical failures in 2023 or July 2025. He confirmed that aviation safety was not compromised during the event.
UK Transport Secretary Heidi Alexander described the disruption as ‘completely unacceptable’ and has ordered the Civil Aviation Authority (CAA) to conduct an independent review to determine why the defect was not detected sooner. Meanwhile, airlines such as Ryanair have called for the resignation of NATS leadership due to the ongoing instability of the national infrastructure.
Entities
Civil Aviation Authority · Heidi Alexander · Martin Rolfe · NATS · National Air Traffic Services · Ryanair · United Kingdom
Claims
What the coverage asserts, and how many sources carry each claim.
- [● 18 SOURCES] The air traffic control outage was caused by a software defect in a specific subsection of the flight data system. www.karsmanset.com · centreline.com.pk · www.forchecaudine.com · theeyeofmedia.com · boardingarea.com · +12 more
- [DISPUTED] The outage resulted in the cancellation of over 2,000 flights. www.karsmanset.com · centreline.com.pk · www.forchecaudine.com · theeyeofmedia.com · boardingarea.com · +14 more
- [● 9 SOURCES] UK Transport Secretary Heidi Alexander ordered the Civil Aviation Authority to conduct an independent review of the incident. centreline.com.pk · theeyeofmedia.com · wtop.com · www.theguardian.com · dete.gr · +4 more
- [● 2 SOURCES] The disruption affected more than 330,000 passengers, with 155,000 cancellations and 180,000 delays. china.timesofnews.com · www.rtl.be
- [● 11 SOURCES] The September 8 incident was not caused by military intervention or related to previous outages in 2023 or July 2025. www.karsmanset.com · centreline.com.pk · theeyeofmedia.com · boardingarea.com · china.timesofnews.com · +6 more
- [● 19 SOURCES] The software defect occurred within a millisecond during the processing of a manual aircraft code request. centreline.com.pk · www.forchecaudine.com · boardingarea.com · adevarul.ro · www.corcianonline.it · +13 more