The UK’s Civil Aviation Authority is reviewing the technical issues that caused NATS to shut down its computer systems on August 28, which saw hundreds of flights delayed and cancelled.
A preliminary technical report published following the incident sets out the causes of the issue and actions taken to rectify and mitigate the effects.
It found the problems occurred due to an anomaly that forced the system to stop processing flight plans. According to the report the “plan included two waypoints along its route that were geographically distinct but which have the same designator”.
The system was closed to maintain safety and required manual operation to continue service.
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.
The UK Civil Aviation Authority (CAA) will now independently review the wider issues around the system failure and how NATS responded to it. The results of the review will be published at the end of this month.
The CAA said that if it finds that NATS might have breached its statutory and licensing obligations, the regulator will take any appropriate steps.
NATS’ main purpose is to deliver a safe air traffic control system in the UK, but among other things, the organisation must also take all reasonable steps to ensure that the demand for air traffic services is met.
Rob Bishton, joint-interim chief executive at the CAA, 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.”
Responding to NATS’ preliminary report into the air traffic control technical failure, the UK Government’s Transport Secretary Mark Harper said, “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 1500 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.
Martin Rolfe, NATS CEO said, “I would like to apologise again for our technical failure. While we resolved the problem quickly.
“NATS exists to allow everyone flying in UK airspace to do so safely. Our systems enable our air traffic controllers to deliver this service all year round. These have several levels of backup and allow us to manage around 2 million flights per year in some of the busiest and most complex airspace in the world safely and efficiently.
"Very occasionally technical issues occur that are complex and take longer to resolve. In the event of such an issue our systems are designed to isolate the problem and prioritise continued safe air traffic control. This is what happened yesterday.
"At no point was UK airspace closed but the number of flights was significantly reduced. Initial investigations into the problem show it relates to some of the flight data we received. 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.”