The aviation regulator is to hold an independent review into the air traffic control system meltdown that saw hundreds of flights delayed and cancelled on August bank holiday Monday.
The Civil Aviation Authority will independently review the wider issues around the system failure and how National Air Traffic Services (Nats) responded to the incident which airlines say cost them £100 million.
The announcement came as Nats issued a preliminary report into the incident.
The technical report sets out the causes of the issue with a flight plan processing sub-system and actions taken to rectify and mitigate the effects.
It found the incident occurred due to an anomaly that forced the system to stop processing flight plans. The system was closed to maintain safety and required manual operation to continue service.
But the scale of the disruption that followed was significant and meant some passengers faced long delays, in some cases, waiting several days for alternative flights, according to the CAA.
Airlines worked around the clock, putting on extra capacity to resolve the issue. Carriers have obligations to look after their passengers in these circumstances and bring them home as soon as possible.
The report confirmed that safety was maintained throughout the incident and that a solution has been implemented to avoid any possible recurrence.
Nats insisted: “This scenario had never been encountered before, with the system having previously processed more than 15 million flight plans over the five years it has been in service. Steps have been taken to ensure the incident cannot be repeated.”
However, the CAA warned that it will take “any appropriate steps” if there is evidence that suggests Nats may have breached its statutory and licensing obligations.
The regulator’s review will also “set out lessons to be learned for the future for the benefit of consumers and the industry”.
Details will be published by the end of the month.
Nats chief executive Martin Rolfe said: “Keeping the sky safe is what guides every action we take, and that was our priority during last week’s incident.
“I would like to reiterate my apology for the effects it had on so many people, including our airline and airport customers. Incidents like this are extremely rare and we have put measures in place to ensure it does not happen again.
“Our preliminary report, provided to the CAA this week, details what caused the incident, how we responded and the steps already taken to prevent recurrence. We welcome any further review of the incident that the CAA wishes to conduct.”
CAA joint-interim chief executive Rob Bishton said: “Millions of passengers every year rely on air traffic control to work smoothly and safely.
“The initial report by Nats raises several important questions and as the regulator we want to make sure these are answered for passengers and industry.
“If there is evidence to suggest Nats may have breached its statutory and licensing obligations we will consider whether any further action is necessary.”
Transport secretary Mark Harpersaid: “I welcome Nats’ preliminary report outlining the facts of last week’s air traffic control technical failure – particularly the confirmation that there were no safety issues as a result.
“I also welcome the CAA’s announcement of an independent review to dig deeper into this event and understand whether there are any further steps to be taken to improve the resilience of the air traffic control system.
“Thousands of passengers faced disruption as a result of the failure, with over 1,500 flights cancelled and hundreds more delayed.
“I once again want to echo Nats’s apology to those who were caught up in it, with a technical fix now identified to ensure that such an incident does not recur.
“I will chair a further meeting between Nats, the CAA and the aviation industry tomorrow to allow Nats to present their findings and consider initial feedback from airlines.”
Which? Travel editor Rory Boland said: “The air traffic control outages last week caused complete chaos for UK travellers – with many sleeping on airport floors or left out-of-pocket after paying for extra accommodation or new flights to get home.
“While passengers understood that this was not an issue caused by airlines, they were understandably frustrated by the poor communication and lack of care they received from carriers.
“The Civil Aviation Authority urgently needs to investigate what caused the air traffic control outages, as well as airlines’ response, to ensure passengers are never left in this situation again.”