NATS publishes preliminary report on technical incident of 8 September
NATS Releases Initial Findings on September 8th Technical Failure
Date: 18 September 2026
Source: NATS Media Centre
NATS, the primary entity responsible for air traffic services in the United Kingdom, has issued a preliminary report detailing the sequence of events that led to significant travel chaos earlier this month. This initial investigation was conducted at the request of the Secretary of State for Transport, Heidi Alexander.
While a comprehensive final report is still pending, this document outlines the root cause and the steps taken toward resolution.
Root Cause Analysis
Chief Executive Officer Martin Rolfe has explicitly clarified that this event was not linked to the significant system failure experienced in August 2023. Furthermore, he debunked theories suggesting military intervention played any role.
The failure was traced to a software defect within a narrow segment of the flight data system coding. Specifically, the error occurred within the National Airspace System (NAS).
The Technical Failure Sequence
The issue centered on how the system handles aircraft identification codes. While these are typically assigned automatically, the system allows for manual requests.
Operational Impact
Because the corrupted data reduced the information available to air traffic controllers, NATS had to implement strict traffic limitations to ensure the safety of all aircraft.
Scope of Disruption
| Feature | Localized Issue | National Response |
|---|---|---|
| Affected Area | London Area Control centre | Entire UK Airspace |
| Altitude Impact | Primarily above | All levels (for system reset) |
| Reason for Scale | Software bug in specific sector | Necessity to restart NAS & reload data |
Timeline of Recovery:
- Active Restrictions: Approximately 6 hours.
- System Normalization: Same evening of September 8th.
- Passenger Recovery: Over 2 days to clear the backlog.
- Total Impact: Hundreds of thousands of travelers disrupted.
Executive Statement
Martin Rolfe expressed deep regret over the incident, emphasizing the balance between efficiency and safety:
"I would like to apologise again, very sincerely, to everyone who was affected last week. It’s our job to get people where they want to go, quickly and without delay and we are devastated when that goes wrong. However, our primary role is to keep our skies safe, and everyone who flies through them. At no point last week was safety in question."
Future Mitigation and Investment
NATS is currently managing the situation through a phased approach:
- Identify the specific subsection of corrupted code.
- Implement immediate mitigation measures.
- Complete safety testing for the permanent fix.
- Deploy the permanent software update.
Regarding long-term infrastructure, NATS has maintained a heavy investment schedule. The financial commitment can be summarized as:
Additionally, NATS intends to propose a further investment of to the Civil Aviation Authority (CAA) to be utilized by the end of 2033.
Contact Information:
For further inquiries, the NATS Press Office can be reached at 01489 615 945 (Standard hours) or 01489 445 699 (Out of hours).