Cancelled flights: Air traffic disruption caused by flight data issue

The National Air Traffic Services (Nats) said the data saw primary and back-up systems suspend “automatic processing”.

Disruptions have seen UK passengers sleeping on airport floors, or having to book alternative routes.

Nats said there were no signs the failure was caused by a cyber-attack.

The organisation has “crucial questions to answer”, the head of one industry body said.

Willie Walsh, head of the International Air Transport Association, called the failure “unacceptable”.

The incident is to be investigated by the Civil Aviation Authority (CAA).

Nats first confirmed the issue just before midday on Monday, and about three hours later said it had identified and remedied the issue.

On Tuesday evening Nats chief executive Martin Rolfe said: “Initial investigations into the problem show it relates to some of the flight data we received.

“Our systems, both primary and the back-ups, responded by suspending automatic processing to ensure that no incorrect safety-related information could be presented to an air traffic controller or impact the rest of the air traffic system.”

He said that “very occasionally technical issues occur that are complex and take longer to resolve.

“In the event of such an issue our systems are designed to isolate the problem and prioritise continued safe air traffic control.”

Passengers have been warned to expect knock-on disruption in the coming days.

The Department of Transport said it had approved night flying to all UK airports it regulates to alleviate the backlog in UK flights.

It follows a meeting of Nats, the CAA, airlines, airports, trade bodies and Border Force, chaired by Transport Secretary Mark Harper.

Speaking after the meeting, Mr Harper warned again that the knock-on effects of Monday’s disruption are likely to continue over the coming days, and said passengers due to travel should check with their airlines before heading to the airport.

Mr Walsh, of the IATA, said he feels for passengers who continue to suffer “huge inconvenience” and airline staff put under “considerable additional stress”.

He said: “Nats has crucial questions to answer about their responsibility for this fiasco.

“The failure of this essential service is unacceptable and brings into question the oversight of the CAA who are required to review the Nats resilience plan under the terms of its licence.”

He added that airlines would “bear significant sums in care and assistance charges, on top of the costs of disruption to crew and aircraft schedules. But it will cost Nats nothing.”

Nats has said the problem was a “technical issue” with its flight planning system which meant the plans had to be processed manually, which could not be done at the same volume, so it had to reduce the number of planes flying.

The PM’s official spokesperson said the exact cause would be investigated by the Civil Aviation Authority and then submitted to government.

“The information we have is that there was not a cyber-attack,” they added.

Asked about reports that a French data entry error was responsible for the outage, the spokesperson said they would not comment on “speculation”, adding: “I’m not going to pre-empt the work that needs to be done.”

They added that they were “not aware of any specific conversations” between French counterparts and officials.

Passengers have recounted how they faced huge disruption because of the issue.

Sarah Skellern is one of thousands of passengers caught up in the aftermath, with many unable to return home to the UK or fly abroad for long-booked holidays.

Mrs Skellern, from near Preston, Lancashire, described “absolute chaos” at Palma de Mallorca Airport, after waiting on an aircraft for six hours before her Jet2 flight on Monday was cancelled.

After leaving the plane, Mrs Skellern said she and her husband Barry, and two boys Toby, 10, and Gabe, eight, were left to find their own accommodation. A lack of local hotels meant they had little choice for a bed but the Spanish airport floor.

Aviation data firm Cirium said that as of 9:00 BST on Tuesday, 147, or 5%, of UK departing flights had been cancelled as well as 134, or 5%, of arrivals.

Heat hrow Airport – the world’s busiest two-runway airport – said on Tuesday that its schedule remained “significantly disrupted”.

EasyJet had been disrupted on Tuesday but by the evening said it was now operating normally.

Aviation analyst Sally Gethin said the disruption in the aftermath of the technical fault will last for days, saying there could be a “knock-on effect into later this week”.

Cirium said 790 departing flights were cancelled on Monday, which it said was equivalent to about 27% of all departures, and 785, or about 27%, of incoming flights.

Heat hrow had the highest number of cancellations, Cirium said, followed by Gatwick and Manchester.