The UK’s air traffic control chief has said that "incorrect" flight data was the cause of the massive disruption that affected thousands of passengers stuck in planes and at airports as hundreds of flights to and from the country were cancelled, with knock-on effects continuing on Wednesday.
Martin Rolfe, the chief executive of National Air Traffic Services (NATS) which had faced the “technical issue” that triggered the chaos on Monday, said an initial investigation had found the failure was caused by flight data which its system could not interpret.
He also reiterated the government’s previous statement that it was not caused by a cyber-attack.
“Initial investigations into the problem show it relates to some of the flight data we received,” said Rolfe.
“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. There are no indications that this was a cyber-attack,” he said.
The air traffic chief reassured passengers that since Monday afternoon all NATS systems have been running “normally” but acknowledged that the “knock-on effects” continue to be felt at a particularly busy travel time of the year over the summer holidays.
Some reports have suggested the chaos may have been caused after a French airline misfiled its flight plan. Without confirming or denying the reports, Rolfe told broadcasters in interviews that the issue could be related to a single flight plan.
“We know it is something in the flight data and we will get to the bottom of it and understand why. We are conducting an investigation, we will conduct it incredibly thoroughly,” he added.
NATS – which is in charge of handling 2 million flights a year to and from the UK – said it has identified the issue around the way the system and "several levels of backups" reacted to the incorrect data, which should prevent similar delays in future.
It is, meanwhile, working with the UK’s Civil Aviation Authority (CAA) on the investigation and said the conclusions of that report will be made public.
As a result of the incorrect data, flight plans had to be uploaded to systems manually, slowing or cancelling air traffic across the UK. Thousands of passengers were affected, with many forced to spend the night at airports around the world and several still waiting for rescheduled flights.
Analysis of flight data found around 281 flights, including departures and arrivals, were cancelled on Tuesday at the UK's six busiest airports – 75 at Gatwick, 74 at Heathrow, 63 at Manchester, 28 at Stansted, 23 at Luton and 18 at Edinburgh.
The UK’s Department of Transport said it had approved night flying, usually restricted, to all UK airports it regulates to help clear the backlog.
The system failure is estimated to cost airlines GBP 100 million, according to the International Air Transport Association (IATA).
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