LONDON, Sept 9 (Reuters) - Britain's NATS air traffic control provider has a week to investigate the systems failure that halted flights and stranded hundreds of thousands of passengers, the government said, as pressure mounts on its chief executive.
Travel disruption continued on Wednesday after flights resumed at major airports following Tuesday's hours-long outage, which led to 2,000 cancellations and cost airlines millions of pounds.
The outage was the second major NATS failure in three years.
Transport minister Heidi Alexander summoned NATS CEO Martin Rolfe to explain what went wrong. A spokesperson for Prime Minister Andy Burnham said the government had confidence in Rolfe but gave him one week to report back on the incident.
After her meeting with Rolfe, Alexander told parliament that she believed the outage was not caused by a cyberattack, but added, "I do not believe this issue was unavoidable."
She announced a separate, independent review by the Civil Aviation Authority, which would report back in six months.
"I am clear that passengers should not have to face this disruption, I have therefore asked the CAA to conduct an independent review to establish cause and ensure that our air traffic control systems can get passengers to where they need to be," she said.
TRAVEL CHAOS
The last NATS shutdown in August 2023 caused travel chaos, costing airlines £100 million ($136 million), and there was also a radar-related technical issue in July 2025, which affected major airports including Britain's largest, Heathrow.
Michael O'Leary, group CEO of Ryanair, told Reuters the outage was "an absolute rerun" of what happened in 2023, when a rogue flight plan caused the shutdown, reiterating his repeated call for Rolfe to step down.
A NATS spokeswoman said it was not the same issue and instead affected the flight data system.
"We will conduct a full investigation to establish the root cause and identify any further action required," she said.
Aviation analytics company Cirium confirmed about 2,000 flights to and from UK airports had been affected by the outage on Tuesday and Wednesday combined, with 30% of scheduled departures grounded on Tuesday and 5% on Wednesday.
The CAA said passengers would generally not be entitled to compensation because the disruption was likely to qualify as an "extraordinary circumstance". Airlines must still provide refunds or rebooking for cancelled flights, plus meals, accommodation and reasonable expenses for stranded passengers.
Airlines UK, which represents the industry, wrote to the government to register its concern.
"The latest NATS failure has again exposed a gap in the UK’s aviation regulatory framework. Airlines are expected, in supporting passengers, to absorb the costs of disruption, even when the cause lies entirely outside their control," Tim Alderslade, CEO of Airlines UK, said in a statement.
KNOCK-ON IMPACTS AS AIRCRAFT OUT OF PLACE
Ryanair said its losses from Tuesday's outage were £3 million ($4 million) so far, after it cancelled 260 flights affecting 48,000 passengers.
British Airways on Tuesday cancelled or diverted 100 flights with tens of thousands impacted, and said on Wednesday 190 flights had been cancelled.
As operations restarted, Britain's main airports - including London's Heathrow and Gatwick hubs - said passengers should check with their airline before heading to the airport.
"We are expecting knock-on impacts as aircraft and crew reposition," the UK's busiest hub said in a statement.
NATS, a public-private partnership partly owned by airlines including British Airways and easyJet, pension funds and the government, paid its owners £175 million in dividends in 2025.
Ryanair is suing NATS in London's High Court for more than £7 million over the 2023 outage and has called on it to reinvest profits in performance improvements and staffing.
(Reporting by Sarah Young, Sam Tobin, Joanna Plucinska, Alistair Smout and William James; editing by Michael Holden, Toby Chopra, Ros Russell)
