A millisecond-long software defect in the UK's National Air Traffic Services (NATS) system corrupted flight data on 8 September, triggering a six-hour outage that cancelled more than 2,000 flights and left hundreds of thousands of passengers stranded for over two days. NATS said the fault stemmed from a legacy bug triggered by a rare combination of simultaneous processing requests, and that a temporary fix is in place while a permanent solution undergoes safety testing. In response, UK Transport Secretary Heidi Alexander has ordered the Civil Aviation Authority (CAA), the country's aviation regulator, to conduct an independent review of NATS's findings and investment plans within six months, as airlines demand compensation and some, including Ryanair, call for the resignation of NATS chief executive Martin Rolfe following what they describe as the third major UK air traffic control failure since summer 2023.