Airlines Scramble to Restore Service After UK System Outage

Siddharth Philip and Kate Duffy, Bloomberg News

Passenger airplanes, operated by British Airways, at London Heathrow Airport. Photographer: Chris Ratcliffe/Bloomberg , Bloomberg

(Bloomberg) -- Airlines are rushing to restore flight operations in the UK and repatriate stranded passengers and planes after the worst air-traffic outage in a decade led to hundreds of delays and cancellations on one of the busiest days this travel season.

British Airways and EasyJet Plc told passengers due to fly on Tuesday that they shouldn’t travel to the airport without checking the status of their flight as it may be delayed or canceled. Both carriers offered those due to depart Monday or Tuesday free changes to flights to a later date, with EasyJet also providing refunds.

London Heathrow showed 200 delayed flights and 38 cancellations on Tuesday, according to Flightradar24. That compares with more than 170 axed flights on Monday. Gatwick airport, the second major hub in London, suffered 26 cancellations on Tuesday, the data show.

Even as the systems were restored at UK airspace manager NATS, returning to normal service could take several days because aircraft will be put out of position. The glitch on Monday coincided with one of the most active extended travel weekends, with the UK off on a national holiday and summer-vacation travelers returning home, leaving thousands of passengers stranded in places they hadn’t planned to be.

Transport Secretary Mark Harper said in an interview on ITV’s Good Morning Britain that “an outage of this magnitude hasn’t happened for nearly a decade.” The government has ruled out a cyber attack, while the cause for the incident remains under investigation.

In total, 790 flights leaving UK airports on Monday were canceled — equivalent to about 27% of all departures — and almost the same amount of incoming flights were axed, according to aviation analytics firm Cirium. Ryanair Holdings Plc said more than 20 of its aircraft were unable to get back to their home bases on Monday night.

“Its not acceptable that UK NATS simply allow their computer systems to be taken down and everybody’s flights get canceled or delayed,” Michael O’Leary, Ryanair’s chief executive officer, said in a video posted on X.

While airlines provided the possibility of rebooking onto other flights, claiming compensation might prove difficult for passengers given the extraordinary circumstances of the outage, according to the UK Civil Aviation Authority.

Wrong Plan?

“While the majority of passengers will still be able to travel, there will unfortunately be some disruption on some routes, including flight cancellations,” a spokesperson for London’s Heathrow airport said. “It is important for all passengers to check the status of their flight with their airline before traveling to Heathrow.”

The meltdown on Monday occurred after the automated flight planning system was knocked out at the central Swanwick operations room about 100 kilometers (60 miles) southwest of London. That forced planners to revert to manual input, meaning they couldn’t manage the same volumes.

While NATS gave no cause for the glitch, The Times reported that issue could have been the result of an incorrectly filed plan by a French airline, according to sources it didn’t identify.

NATS manages its systems from Swanwick, coordinating the airspace over England and Wales. When Swanwick opened nearly five years late in 2002, it was 30% over budget following some software glitches. Its prime contractor was Lockheed Martin Corp.

(Updates with comment from Ryanair CEO in seventh paragraph.)