The aviation regulator closed the file on Britain's last air traffic failure in June 2026, calling all 34 safety recommendations complete. NATS failed twice more within three months, reopening exactly what had just been closed.
Estimated reading time: 6 minutes
In short. On 19 June 2026 the Civil Aviation Authority published CAP 3193A, closing the last two of the 34 recommendations from its independent review into NATS' August 2023 flight planning failure, and telling the Department for Transport that "this concludes our reporting requirements... in relation to this event" [1]. One of the closed recommendations required NATS to ensure flight restrictions, if needed at all, were "kept to a minimum" [1]. On 8 September 2026, NATS applied exactly such restrictions after a flight data system failure, disrupting more than 2,000 flights [3]. Thirteen days later, a second failure at NATS' Prestwick centre cancelled 227 more [5]. The CAA's own new review, ordered within weeks, is now tasked with assessing "the extent to which" those same recommendations "have been effectively implemented" [2], the exact question CAP 3193A had just answered. Two documented mistakes: four stars.
On 28 August 2023, a single flight plan with a duplicated waypoint identifier crashed the flight planning system NATS uses to route aircraft across England and Wales, grounding or delaying flights for more than 700,000 passengers. An independent panel chaired by Jeff Halliwell reported in November 2024 with 34 recommendations, split between NATS, the CAA, airlines and airports, and government, covering everything from software testing to how early airlines are warned of disruption [4]. The CAA has been publishing progress reports on that list ever since. CAP 3193A, published 19 June 2026, is the last one.
A file closed in June
CAP 3193A closed the final two outstanding items. The more significant of the two, R1, had told NATS to "review in detail its contingency arrangements for significant disruption to ensure that maximum airspace capacity continues to be available without the need for flight restrictions for as long as possible, and if restrictions are required, that they are kept to a minimum" [1]. The CAA's sign-off was unqualified: "NATS has provided further evidence addressing the remaining assurance points. The Civil Aviation Authority has reviewed this evidence and is satisfied that the intent of the recommendation has been fully met. We consider this recommendation to be complete" [1]. The document's conclusion goes further than closing one item on a list: "the CAA confirms that all recommendations arising from the Independent Review of the August 2023 NERL flight planning system failure have been actioned. This concludes our reporting requirements to the Department of Transport in relation to this event" [1].
NATS' own June 2026 Annual Report struck the same note about an earlier, smaller incident on 30 July 2025, a radar-related fault that had cancelled over 150 flights out of Heathrow and elsewhere: "NATS response to the 30 July 2025 incident effectively mitigated the risk of a recurrence" [6]. By the end of its 2025/26 financial year, on paper, NATS had a clean sheet on resilience.
Two failures in thirteen days
On 8 September 2026, a software defect in NATS' National Airspace System took down live flight data at the London Area Control centre, the same Swanwick facility behind the 2023 failure. NATS' own preliminary report, published 16 September, is direct about what followed: "Restrictions were applied to reduce the number of aircraft that could enter each controller's sector, including limiting or stopping departures from UK and overseas airports" [3]. Chief executive Martin Rolfe's foreword to that report does not dispute the characterisation: "That can mean placing restrictions to limit air traffic, as we did on 8 September; we do not do that lightly, and we deeply regret the inconvenience it caused to so many people" [3]. NATS had forecast roughly 8,000 flights that day; EUROCONTROL records showed only 6,094 handled, meaning more than 2,000 were delayed, cancelled or diverted [3].
Thirteen days later, on 21 September, a connectivity fault at NATS' Prestwick centre in Scotland forced a second round of restrictions, cutting capacity across Scottish and northern English airspace. NATS described it as "a connectivity issue with part of our systems network, specific to the operation in Scotland. It is nothing to do with the problem we had earlier this month" [5], a distinction of cause that does nothing to change the outcome R1 was written to prevent. Cirium's count put cancellations at 227 by late afternoon, with Ryanair alone reporting more than 25,000 affected passengers [5].
The regulator reopens its own closed file
Transport Secretary Heidi Alexander asked the CAA to launch a fresh review after the 8 September failure. Its terms of reference, CAP 3315, published 25 September, set out four workstreams. The first instructs the review team to "review the findings, recommendations and actions arising from previous significant UK ATM disruption events, including the August 2023 disruption, and assess the extent to which they have been effectively implemented and remain adequate in addressing both system resilience and the consequences of major disruption" [2]. That is not a new question. It is the question CAP 3193A had already answered, three months earlier, with a one-word verdict: complete.
The political record shows the same claim being repeated even as the ground shifted under it. Trade title Airways Magazine reported that aviation minister Keir Mather, answering an urgent question in the Commons after the 8 September failure, told MPs 32 of the 34 recommendations had been implemented, then corrected himself moments later: "not 32 but all 34 of the recommendations have been implemented" [7]. Hansard's own record of that exchange returned a bot-block on direct access, consistent with Parliament's website elsewhere on this site; the quote above is sourced to the trade press account of it, not read directly off the primary record.
The claims, tested
| The document's own words | What the record actually shows | Verdict |
|---|---|---|
| R1 "fully met"; flight restrictions to be "kept to a minimum" if used at all [1] | NATS applied sector-entry and departure restrictions twice within three months, disrupting over 2,000 flights on 8 September and 227 more on 21 September [3] [5] | The recommendation's intent, not just its paperwork, was tested within the same year it was closed, and the restrictions it existed to prevent happened anyway |
| "This concludes our reporting requirements to the Department of Transport in relation to this event" (19 June 2026) [1] | The CAA's own new review (25 September 2026) is tasked with assessing "the extent to which" the same recommendations "have been effectively implemented" [2] | What was declared concluded in June was reopened by the same regulator in September |
| NATS' Annual Report: its response to the 30 July 2025 incident "effectively mitigated the risk of a recurrence" [6] | Two further system failures followed within the same financial year's immediate aftermath, on 8 and 21 September 2026 | The mitigation claim did not hold for the length of time implied by publishing it in an annual report |
Credit where due
NATS published its preliminary report on the 8 September failure within eight days, naming the affected system, the restrictions applied and the passenger impact in plain figures, not euphemism. The CAA's new review was commissioned within weeks of the failure, with published terms of reference and an independent challenge panel, rather than being left to an internal process with no public record. And CAP 3193A itself is not evasive about what it claims: it names the two recommendations it closes, quotes their original wording, and states its conclusion in a single unambiguous sentence, which is exactly what let this piece test it directly against what happened next.
Verdict
Four stars, from two documented mistakes. A regulator told the department responsible for aviation that a safety recommendation about minimising flight restrictions was fully met, and a file was closed. Within three months the restrictions happened twice, and the regulator opened a new review to ask, again, whether its own recommendations had worked.
The star score counts two documented mistakes. First, CAP 3193A declared recommendation R1, requiring flight restrictions to be "kept to a minimum", fully met and complete on 19 June 2026; NATS applied exactly such restrictions twice within three months, on 8 and 21 September 2026, disrupting well over 2,000 flights. Second, CAP 3193A stated its reporting requirements to the Department for Transport were concluded; the CAA's own subsequent review, CAP 3315, re-examines "the extent to which" those same recommendations "have been effectively implemented," reopening what had just been closed. Two falls in the 1 to 3 band: four stars; the bands are on the ratings page. NATS' Annual Report claim about the July 2025 incident and the minister's Commons exchange are reported above as context, not counted separately, since both concern NATS' or the minister's own statements rather than the CAA document under teardown here. This piece makes no finding about the personal conduct of any named individual; the claims tested are the regulator's own published words against the public record of what followed. All sources below were fetched directly on 8 November 2026; Hansard's record of the Commons exchange returned a bot-block on direct access, noted above, and its quoted content is sourced to the trade press account cited.
Sources
- CAP 3193A: Addendum to CAP3193, Final Status Update on Recommendations from the Independent Review of NERL's August 2023 Flight Planning System Failure (PDF), Civil Aviation Authority, published 19 June 2026
- CAP 3315: Terms of Reference for CAA Review of UK Air Traffic Management Resilience, System Renewal and Future Capability (PDF), Civil Aviation Authority, published 25 September 2026
- NATS Major Incident Preliminary Investigation Report: NAS Incident 08 September 2026 (PDF), NATS (En Route) Plc, report date 16 September 2026
- CAP 3109: Recommendations from the Independent Review of NERL's August 2023 Flight Planning System Failure, update on progress (PDF), Civil Aviation Authority, published 2025
- NATS Technical Failure At Prestwick Disrupts UK Flights; CAA Rules Out Compensation, Aviation Today News, 22 September 2026
- NATS Holdings Limited Annual Report and Accounts 2026, Governance Report (PDF), NATS Holdings Limited, published June 2026
- UK Regulator to Review NATS Outage as Minister Says Resilience Falls Short, Airways Magazine, 12 September 2026