Britain's air traffic control provider NATS says a software defect in a specific part of its flight-data system caused the major disruption on 8 September 2026 that led to more than 2,000 flight cancellations and affected hundreds of thousands of passengers.

What NATS says went wrong

According to NATS chief executive Martin Rolfe, the failure was triggered when a high-priority request interrupted a standard aircraft-identification-code process. The interruption lasted only milliseconds, but it activated protective backup procedures that sharply reduced the system's operating capacity.

NATS says the incident was not caused by human error, military activity or the same technical problem behind earlier outages in 2023 and 2025. The company has introduced temporary mitigation measures while engineers test a permanent software fix.

Why the outage caused such widespread disruption

Air traffic control systems must maintain safe separation and reliable identification of aircraft. When a core flight-data function degrades, the system can deliberately reduce the number of flights it processes. That protects safety but can quickly produce delays, cancellations and knock-on disruption across airport networks.

Reuters reported that about 2,000 flights were cancelled after the outage. Associated Press reporting likewise said the preliminary NATS findings linked the disruption to a software glitch in the flight-data system.

Independent review ordered

UK Transport Secretary Heidi Alexander has asked the Civil Aviation Authority to conduct an independent review of the incident and NATS' findings. The review is expected to examine the technical failure, the resilience of the system and whether further investment or regulatory changes are needed.

NATS has said aviation safety was not compromised during the incident.

What passengers should know

The immediate outage has been resolved, but travellers should continue to check directly with their airline and departure airport for any residual schedule changes. Compensation or re-routing rights can depend on the circumstances of an individual journey and the applicable passenger-rights rules.

FlyingEze will update this report if the Civil Aviation Authority publishes material new findings or NATS announces the permanent technical fix.