UK air traffic control fault disrupts over 1,000 flights, airlines call for reform; Air India issues advisory for flyers

Flights at major British airports were disrupted on Tuesday after a technical fault at air traffic control provider NATS affected its flight data processing system, leading to more than 1,000 cancellations and hundreds of delays.

According to Reuters, NATS said the issue was resolved at 1834 GMT and that "safety was not compromised". The provider said it was operating normally but warned that it would take time to clear the backlog created by the disruption.

NATS CEO Martin Rolfe told Sky News that the company had not "fully done the investigation" into the cause of the technical issue.

"We don't have an idea yet of exactly what went wrong," Rolfe said.

More than 1,000 flights cancelled

Flight-tracking website Flightradar24 said 1,300 flights to and from UK airports were cancelled on Tuesday, while another 177 flights had been cancelled for Wednesday, nearly all at Heathrow.

Heathrow said arrivals had been suspended for the remainder of Tuesday, while departures had resumed. The airport warned that disruption was expected to continue.

FlightAware data showed around 490 departures were delayed at six airports -- Heathrow, Gatwick, London City, Luton, Edinburgh and Bristol -- as of 1518 GMT. Another 525 arrivals at the six airports were either cancelled or delayed.

At Heathrow, 38 of 661 scheduled arrivals had been cancelled or were unable to operate, according to aviation analytics company Cirium. British Airways was the most affected carrier at the airport, cancelling 16 of 333 scheduled departures.

"The severity of the issue means there will be a significant knock-on impact for customers and colleagues," British Airways said in a statement.

Airlines call for NATS reform

The disruption has renewed questions about the resilience of Britain's aviation infrastructure, coming three years after a flight-plan processing failure at NATS caused widespread disruption.

Aviation analyst John Strickland said delays can quickly cascade through Europe's tightly scheduled aviation network.

"A few hours of outage may on the face of it sound limited but the impact is enormous when a substantial number of airports across the UK are affected," Strickland said, according to Reuters.

Ryanair said around 150,000 of its passengers had been affected by delays of up to eight hours and that it had cancelled more than 200 flights. The airline's Chief Operating Officer Neal McMahon called on NATS CEO Martin Rolfe to resign.

Wizz Air also called for urgent reform, saying airlines, passengers and airports should not continue to bear the consequences of recurring system failures.

"A critical national infrastructure provider should not repeatedly bring the aviation system to a standstill. NATS is simply not fit for purpose in its current form," Wizz Air said in a statement.

Air India flights affected

Air India flights operating to and from UK airports had also been impacted.

In a traffic advisory, the airline said it had been forced to divert, delay or cancel multiple flights scheduled to operate to and from UK airports.

Air India also warned that the disruption could affect some of its other services because its aircraft and crews had been left out of position following the incident.

The airline advised passengers to check the latest status of their flights before proceeding to the airport. Air India said it was closely monitoring the situation and making efforts to minimise disruptions.

"We regret the inconvenience caused by this unfortunate situation, which is entirely beyond our control, and thank our passengers for their patience and understanding," the airline said in a statement on X.

Regulator seeks report

Britain's aviation regulator said it would expect NATS to share a full report of Tuesday's incident. The Civil Aviation Authority said it would then consider whether further steps were needed to secure the reliability of the UK's air traffic control system.

In 2024, the CAA had said NATS needed to review its contingency plans for outages after an automatic flight-plan processing malfunction the previous year caused disruption across Britain's airports.

In July last year, a radar-related technical issue in Britain's air traffic control system also disrupted flights for more than four hours at major airports in London and elsewhere, including Heathrow.