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The meltdown of the UK’s air traffic control system last August, which impacted over 700,000 passengers, was originally caused by the failure to process flight plan data from just a single flight from Los Angeles to Paris.
The UK Civil Aviation Authority (CAA) appointed an Independent Review Panel to produce an interim report into the incident. During the investigation, it was found that it took around 90 minutes for an engineer to arrive on-site to perform the necessary restart of the air traffic control system, further compounding the delays faced by passengers. As it was a bank holiday, the engineers were working from home and were not permitted to perform the restart remotely.
Airlines planning to operate flights through controlled airspace are routinely required to file a flight plan containing information such as aircraft type, speed and routing.
But both the primary and secondary systems for the central air traffic control system failed to process data for the Los Angeles to Paris flight, resulting in critical exception errors being generated. This caused each system to place itself into maintenance mode to prevent the transfer of apparently corrupt flight data to the air traffic controllers.
At that point, further automated processing of flight plan data was no longer possible and the remaining processing capacity was entirely manual.
To fix the issue, the engineers followed standard escalation protocols, which unfortunately meant they did not call for assistance from the remote engineer for more than three hours after the initial failure.
The CAA estimates that out of the 700,000 passengers impacted, 300,000 had their flight cancelled entirely, 95,000 faced delays of over three hours, and a further 300,000 had shorter delays.
The interim report finds that while the cause of the incident is now understood, it is still investigating the breakdown of communications that led to the issue not being addressed for some time.
Jeff Halliwell, chair of the Independent Review Panel, said: “In developing the interim report, the panel has engaged with a wide range of stakeholders to ensure the final report reflects a diverse range of perspectives.
“In order to produce effective recommendations, the panel has further lines of enquiry it is exploring in order to build a better understanding of how the aviation system can improve.”
The panel expects to produce a full report later this year, which will be submitted to the CAA and shared with the Department for Transport.
