UK air traffic control outage caused by software defect, says operator

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 had last week demanded NATS produce a report on the matter and also 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….

"It is crucial that our national infrastructure is fit for the future."The incident followed a shutdown in August 2023 which caused travel chaos, costing airlines £100 million ($136 million).

A smaller technical issue which NATS was behind in July 2025 also caused 150 cancellations.Ryanair, Europe's biggest airline, has repeatedly called for Rolfe to resign since the 2023 failure.The NATS report on the latest incident was triggered by a request for an identification code from an aircraft being followed by a request for a higher-priority activity, pausing the first request."Had the higher-priority request arrived even one millisecond earlier or later,….

UK air traffic control outage caused by software defect, says operator Outage affected hundreds of thousands of passengers last week.