WASHINGTON: The Trump administration has blamed overloaded air traffic control systems for a communications failure that disrupted flights across the United States, forcing the Federal Aviation Administration (FAA) to impose a nationwide ground stop that was later lifted.
Transportation Secretary Sean Duffy said overloaded switches and routers contributed to the technical failure, which affected communications at multiple air route traffic control centres on Friday.
The FAA ordered airlines to suspend departures nationwide after the disruption raised safety concerns. The ground stop remained in place for more than four hours before being lifted on Friday evening.
Duffy said instability in radar and communications systems had affected air traffic control operations. He said the immediate technical problem had been resolved and flights could resume safely, but warned that it would take time for normal operations to return.
The disruption caused widespread cancellations and delays at airports across the country. Flight-tracking data showed more than 4,700 flights cancelled and around 10,000 delayed on Friday. Airlines continued working on Saturday to restore schedules and reposition aircraft and crew.
Homeland Security Secretary Markwayne Mullin said there was no indication so far that the communications failure was caused by a cyberattack. Authorities are continuing to investigate the incident.
The disruption has renewed concerns over the ageing technology supporting the country's air traffic control network. Duffy has called for an upgrade of the system, including the replacement of outdated equipment.
Although the nationwide ground stop has been lifted, passengers have been warned that delays and cancellations could continue as airlines clear the backlog.
(With inputs from media reports)