NATS published preliminary findings on September 18, 2026, into the software incident that disrupted UK air traffic on September 8.
What the initial investigation found
The provider says a defect affected a component that handles manual requests for aircraft identification codes. A higher-priority message interrupted a request; when processing resumed, the defect corrupted its output and affected subsequent flight-data updates.
With less information available to controllers, traffic restrictions were imposed while the system was restarted and data reloaded.
Recovery and remaining work
NATS says restrictions lasted about six hours. Operations returned to normal that evening, but the passenger-disruption backlog took more than two days to clear.
The company says mitigation is in place while a permanent fix undergoes safety testing and deployment. A full report will follow.
NATS also says the incident was unrelated to its August 2023 outage and rejects speculation about military intervention. These are preliminary findings from the service provider, not a completed independent investigation.
