An air traffic control meltdown in Britain last August that saw flights grounded during a busy travel period was exacerbated by the fact that key personnel were working from home, according to an interim report commissioned by the nation’s aviation watchdog, the CAA.
Thousands of passengers were stranded for days after 1,500 flights were cancelled on August 28, 2023, when the computerized flight planning system at National Air Traffic Services (Nats) shut down because of a glitch.
The CAA’s interim report, which was published on Thursday, showed that fixing the problem was “more protracted than it might otherwise have been” because of the absence of some senior engineers over the bank holiday.
It took one engineer 90 minutes to arrive on site at Swanwick in Hampshire to manually restart the system, according to the report. The most senior engineer on duty was not called for more than three hours after the initial problem emerged. Meanwhile, Nats, which runs the UK’s air traffic services, waited four hours to call the company that built the software, the report added.
The review into the incident showed that the meltdown was triggered by the inability of the Nats computer system to process unusual, but correct, data in a flight plan submitted for a plane crossing UK airspace to Paris from Los Angeles. It indicated that two separate waypoints, or navigational markers, with an identical code triggered a “critical exception error” that forced the system and its back-up to enter a ‘fail-safe’ mode. Navigational markers are submitted by airlines to air traffic controllers in order to minimize the risk of mid-air collisions.
“This report contains damning evidence that Nats’ basic resilience planning and procedures were wholly inadequate and fell well below the standard that should be expected for national infrastructure of this importance,” Tim Alderslade, the chief executive of Airlines UK, said.
Michael O’Leary, the chief executive of Ryanair, explained that “the fact that key Nats engineers were sitting at home during one of the peak travel weekends, combined with findings that Nats has a fundamental lack of pre-planning, documentation, and coordination, clearly demands senior management changes.”
According to the aviation regulator’s estimates, over 700,000 passengers were impacted during the incident, including 300,000 people having their flights canceled.