British air traffic control outage caused by software defect, says operator
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An outage last week led to 2,000 flight cancellations at UK airports and days of disruption.
PHOTO: REUTERS
- British air traffic control operator NATS confirmed a software defect caused last week's outage, leading to 2,000 flight cancellations and millions in airline losses.
- NATS CEO Martin Rolfe said the issue was isolated to a small coding error and did not compromise safety; a permanent fix is being tested.
- Transport minister Heidi Alexander called the disruption "completely unacceptable" and ordered an independent review to ensure future infrastructure reliability.
AI generated
LONDON – British air traffic control operator NATS said on Sept 18 that a software defect caused last week’s outage, which affected hundreds of thousands of passengers.
The incident led to 2,000 flight cancellations and days of disruption, costing airlines millions of pounds as they scrambled to get crews and aircraft back into place and refund passengers.
NATS chief executive Martin Rolfe said the shutdown was not related to a problem in 2023, which also caused widespread disruption, nor was it linked to military intervention – as reported by some media outlets last week.
He added that safety was at no point compromised during the incident.
“This was a software issue in a specific part of our flight data system that we have traced to a small subsection of coding,” he said.
“The issue has been identified, and mitigation is in place while a permanent fix is safety tested and deployed.”
Transport Minister Heidi Alexander, who last week demanded that NATS produce a report on the matter and ordered an independent review by the Civil Aviation Authority, said the disruption was “completely unacceptable”.
“We need to urgently understand why this issue was not discovered and fixed before it caused chaos,” she said in a statement. “It is crucial that our national infrastructure is fit for the future.”
The incident followed a shutdown in August 2023, which caused travel chaos and cost airlines £100 million (S$170 million). A smaller technical issue involving NATS also caused 150 cancellations in July 2025.
Ryanair, Europe’s biggest airline, has repeatedly called on Rolfe to resign since the 2023 failure.
According to NATS’ report, the latest incident was triggered when a request for an identification code from an aircraft was followed by a request for a higher-priority activity, which paused the first request.
“Had the higher-priority request arrived even one millisecond earlier or later, the update would have completed normally,” the report said. REUTERS