The UK air traffic control network meltdown in the summer of last year has been found to have cost airlines around £65 million, according to the Civil Aviation Authority's (CAA) independent review into the August 2023 incident.
“In addition, substantial costs were incurred by passengers, airports, tour operators, insurers, and others,” the report continued. “The panel was unable to accurately quantify these costs. It is likely that the total cost was in the region of £75 to £100 million.”
Not one to remain silent on matters, Ryanair called on the UK government to reform the UK's air traffic control system, labelling it “hopeless”. The airline further attacked the lack of adequate communication from the National Air Traffic Services (NATS) and its system errors during the time of the event.
The report further estimated that over 700,000 passengers were affected by the failure - often for several days. The panel has commissioned a separate consumer research report into the incident, drawing upon customer experience, and was published to coincide with the CAA's new report.
“The incident on August 28, 2024, represented a major failure on the part of the air traffic control system, which caused considerable distress to over 700,000 aviation passengers, and resulted in substantial costs to airlines and airports,” said the chair of the independent review panel Jeff Halliwell.
CAA chief executive Rob Bishton commented: “This final report gets to the heart of what went wrong in August 2023… it is vital that we learn the lessons from any major incident such as this.”
The bank holiday disruption stemmed from an IT outage on NATS' flight plan processing system. The cause of the outage was attributed to the system being unable to process flight plan data for a specific route: LA to Paris (Orly) on August 28, 2023. The processing of this particular flight data resulted in “critical exception errors being generated" and caused both the primary and secondary systems to go into maintenance mode.
After the secondary systems went into maintenance mode - used to prevent incorrect data being sent to air traffic controllers - the automated processing of flight plan data was made impossible. As a result, flight processing could only be completed manually.
The report said there was seven manually operated terminals available for data entry at the air traffic control centre, but staff had “not been trained” to enter full flight plans into the system. At peak periods, the IT system processes around 900 flight plans per hour and a typical busy period will see around 700 and 800 flight plans per hour. Through manual methods, this capacity is reduced to merely 60 per hour.
In addition, with it being a public holiday, NATS engineers were not available on site. “It took 1.5 hours for the [engineer] to arrive on-site to perform the necessary full system re-start which was not possible remotely,” the report said.
NATS had published its own preliminary report into the incident in September 2023, which identified the root cause of the IT failure, underpinned the fact that safety was maintained throughout the incident, and reiterated its apology to all involved. The report said it had found the system had “encountered an extremely rare set of circumstances presented by a flight plan that included two identically named, but separate waypoint markers outside of UK airspace”.
A NATS spokesperson said: “Since 2015, this was the only incident of such scale among the 20 million flights that we have handled, and we will continue to identify and make improvements to continuously improve the service we provide."
The extensive report detailed 34 recommendations to airports, airlines, government and regulators. They vary from contingency arrangement reviews, ensuring onsite coverage from engineers of “sufficient skill levels that are matched to aviation system demand” and the review the diversity of software. Furthermore, the recommendations set out greater consumer protections and support, as well as calling for better communication between aviation operators.
UK airport trade body AirportsUK chief executive Karen Dee said: “We'll continue to work with the whole aviation sector so that incidents such as this are minimised in future.”
The report also recommended that the government consider legislative change to bring the CAA's consumer enforcement powers in line with other sectors and to make alternative dispute resolution (ADR) membership mandatory for all airlines operating in the UK.
“Over the 15 months since this incident, we have worked hard to address the lessons from it, and to ensure this particular issue cannot happen again,” the spokesperson continued. “Our own internal investigation made 48 recommendations, most of which we have already implemented; these include improving our engagement with our airline and airport customers, our wider contingency and crisis response and our engineering support processes. We fixed the specific issue that caused the problem last year as our first priority and it cannot reoccur.”
NATS said it will “study” the report's new recommendations “very carefully” for any that it has not already recommended itself, and said it welcomes and will support the recommendations.
The CAA said it will publish updates on the progress of the recommendations' implementation.