NATS air traffic control outage

Thousands of flights were disrupted across the UK after a major air traffic control system failure, with a new report suggesting that unusual flight data submitted by a military aircraft may have triggered the incident.

The disruption brought parts of the UK's aviation network to a standstill earlier this week, affecting hundreds of thousands of passengers and leading to more than 2,000 cancelled flights.

The failure affected systems operated by NATS (National Air Traffic Services) and lasted for around four hours. Airports and airlines across the country were forced to manage significant disruption, with passengers facing lengthy delays, cancellations and changes to their planned journeys.

A report by the Financial Times, citing people briefed on the incident, said the outage may have been triggered by a flight plan submitted by a UK military aircraft.

According to the report, the data was described as “spurious” and is understood to have caused problems within the flight-processing systems used by NATS.

The precise technical sequence that led to the system failure has not yet been publicly established, and an official investigation remains under way.

The Ministry of Defence has said there was no indication at this stage that the military had made an error. It has also indicated that it would not comment further while the NATS investigation continues.

The incident has also raised questions about the resilience of the systems used to manage Britain's airspace.

According to the Financial Times report, NATS does not currently operate a fully duplicated backup for the affected flight-processing system. The organisation is understood to be undertaking a major overhaul of its technology infrastructure, with the volume of data involved making complete duplication particularly expensive and complex.

The outage has renewed concerns about whether sufficient safeguards are in place to keep Britain's aviation network operating when a critical system fails.

NATS chief executive Martin Rolfe has come under increasing pressure following the disruption.

Transport Secretary Heidi Alexander met with Rolfe after the incident and requested a report into what caused the shutdown. The government has also commissioned an independent review by the Civil Aviation Authority (CAA).

Alexander has said she does not believe the disruption was unavoidable.

The incident is the most significant disruption to Britain's commercial airspace since August 2023, when a separate technical failure resulted in almost 1,600 flights being delayed.

Following that incident, the CAA issued 34 recommendations aimed at improving the resilience of NATS systems. NATS subsequently said those recommendations had been implemented.

The latest outage has prompted strong criticism from airlines, with some industry figures questioning whether the current leadership at NATS should remain in place.

Ryanair chief executive Michael O'Leary has been particularly critical, arguing that the incident demonstrates the need for stronger contingency arrangements rather than further reviews.

The airline industry is now likely to focus heavily on whether the UK's air traffic control infrastructure has adequate backup capacity to prevent a similar event from causing widespread disruption in the future.

The impact was felt across the country.

Some aircraft carrying passengers were reportedly held for several hours while airlines and airports waited for further information. Other flights heading towards the UK were diverted, with some aircraft landing in Germany rather than their original destinations.

For passengers, the disruption created uncertainty over onward connections, hotel arrangements and ground transportation.

At the same time, airlines faced the difficult task of reorganising aircraft and crews while dealing with limited information from the air traffic control system.

Passengers affected by the disruption may also face difficulties when seeking compensation.

Because the delays and cancellations resulted from circumstances outside the direct control of individual airlines, the disruption may fall under the category of “extraordinary circumstances” under UK passenger-rights rules.

That does not necessarily mean passengers have no rights. Depending on the circumstances, passengers may still be entitled to assistance, including food, refreshments and accommodation where appropriate.

Airlines may also have separate obligations depending on the individual journey and the reason for the disruption.

NATS has ruled out a cyber-attack as the cause of the outage, with Martin Rolfe describing the incident as something the organisation had not previously experienced during its decades of operation.

The investigation will now need to establish exactly what caused the system to fail, why the failure was able to affect such a large part of the UK's airspace network and whether existing backup arrangements were sufficient.

The findings of the NATS investigation and the independent CAA review are expected to provide greater clarity over what happened and what changes may be required to prevent another major aviation disruption.

For passengers and the wider travel industry, the incident has highlighted how heavily modern air travel depends on the reliability and resilience of the UK's air traffic control infrastructure.

For passengers with a booked airport transfer, incidents like this are exactly why we track every flight rather than working from the scheduled time: pickups adjust automatically when a flight lands late, and waiting time on an airport collection is free for the first 30 minutes after landing. If your flight is delayed or diverted because of an air traffic control disruption, contact us and we will adjust your pickup rather than charge for a wait that was outside your control.

Written by Airports Transfer for passengers travelling to and from London airports.