MoD denies military aircraft triggered NATS outage as investigation continues

The Ministry of Defence has denied reports that an error linked to a flight plan filed for a military aircraft caused last week’s NATS air traffic control outage.

The denial followed a Financial Times report which claimed that a flight plan submitted by a UK military aircraft triggered the system failure last week, which led to the cancellation of hundreds of flights.

MoD rejects claim over military flight plan

An MoD spokesperson said: “We do not believe there’s any indication of an error on the part of the military.

“Because it’s subject to a live NATS investigation, which is expected to conclude next week, it would be inappropriate for us to comment any further while that investigation is ongoing.”

The Financial Times report cited four people apparently briefed on the incident, who said data submitted as part of a military flight plan had triggered a sequence of events that caused NATS’ flight processing system to shut down.

NATS outage caused widespread disruption

The failure took several attempts to recover and caused widespread disruption across the UK, with departing aircraft grounded and the knock-on effects being felt for days afterwards. 

Heathrow, Gatwick, Stansted, Luton and Manchester were among the airports affected, with disruption also reported at smaller airports across the UK.

More than 2,000 flights were ultimately cancelled across the two days following the outage, affecting more than 300,000 passengers.

About 30% of scheduled UK departures were grounded on the Tuesday alone.

NATS has not publicly confirmed the cause of the outage, saying only that the problem occurred within its flight processing system. Their investigation is continuing. 

NATS said on the afternoon of the incident that it had identified an issue within its flight processing system and that engineers were working to restore normal operations. 

It later said a fix had been implemented and that the system was beginning to recover, but this only came after several hours of widespread disruption.

The effects continued after the system was restored as airlines and airports attempted to reposition aircraft and crews and clear the backlog. 

NATS faces scrutiny over repeated failures

The disruption also prompted renewed scrutiny of NATS following previous technical failures.

An August 2023 outage, which affected more than 1,600 flights and more than 700,000 passengers, was linked to an unusual flight plan that caused NATS’ primary and backup processing systems to enter a fail-safe mode. 

A separate radar-related technical problem also disrupted flights at Heathrow and other UK airports in July 2025.

The latest failure has placed further pressure on NATS chief executive Martin Rolfe. 

Ryanair calls for NATS chief to be dismissed

Transport Secretary Heidi Alexander has ordered NATS to report on the cause of the incident within a week, while the Civil Aviation Authority is conducting a separate independent investigation.

The NATS investigation is expected to conclude next week. 

Ryanair called directly on Alexander to dismiss Rolfe, arguing that repeated failures under his leadership demonstrate that a change at the top is needed.

Ryanair chief executive Michael O’Leary said: “Martin Rolfe’s position as NATS CEO is untenable.”

O’Leary argued that further investigations would achieve little, given previous assurances that resilience would improve after the August 2023 failure.