London, Sept. 14 – A flight plan filed for a UK military aircraft reportedly introduced anomalous data into the National Air Traffic Services flight processing system, triggering UK air traffic control failure that reduced airspace capacity on 8 September 2026. The Financial Times cited four briefed sources on 11 September, two saying military character of the flight was not the cause.
The UK Ministry of Defence disputed suggestions of military error, saying there was no indication of a mistake on its part and declining comment while the NATS investigation remains open, expected to conclude the week beginning 14 September 2026. NATS has not publicly identified the trigger.
NATS said at 13:46 local time on 8 September it was investigating a technical issue affecting departures, confirmed at 15:25 the fault lay in its flight processing system, reported a fix at 16:40 and normal operation at 19:30. Cirium counted more than 2,000 flights affected on 8 and 9 September at Heathrow, Gatwick and Manchester.
Transport Secretary Heidi Alexander told the House of Commons on 9 September she did not believe the failure was unavoidable and asked the Civil Aviation Authority to conduct an independent review reporting within six months considering NATS resilience after a technical report.