The technical failure that led to hundreds of flight cancellations and severe delays for thousands of people traveling in and out of Britain last week resulted from a “one in 15 million chance”, the control service said of air traffic in the country on Wednesday.
“We have processed 15 million flight plans using this system,” Martin Rolfe, the chief executive of Britain’s National Air Traffic Service, told The BBC’s “Today” programme. And the service, he said, was “never seen before.”
On Wednesday, the service published a report based on an internal investigation of the event, detailing what Mr. Rolfe described as “an incredibly extraordinary set of circumstances.”
According to the report, the air traffic control system found two separate pieces of navigational data in a flight plan of an aircraft with the same name. As a result, the system’s primary and backup computer systems both shut down to prevent false information from being passed to the controllers.
The service reverted to manual air traffic control, meaning fewer flights could be processed.
“Keeping the skies safe guides every action we take, and that was our priority after last week’s incident,” Mr. Rolfe said in a statement.
The problem was fixed after a few hours, but 799 outbound and 786 inbound flights were canceled as of Aug. 28, according to Cirium, an aviation analytics company. The disruption continued until August 29, when more than 300 flights were canceled.
Mr Rolfe again apologized to affected passengers, many of whom were stranded at airports or on tarmacs for hours or had to wait days for alternative flights. He said, if the issue recurs, the National Air Traffic Service will handle it.
“Action has been taken to ensure that such an incident does not happen again,” Mark Harper, Britain’s secretary of state for transport, said. wrote on social media on Wednesday.
The Civil Aviation Authority, which oversees aviation safety in Britain, said this Wednesday has started an independent review of the issue and the response to assess whether the National Air Traffic Service breached its obligations. The results will be published by the end of the month, the authority said.
Wednesday’s report came as a New York Times investigation found an alarming pattern of safety lapses and near misses in the United States’ airspace and on airport runways.