WASHINGTON, Nov 13 (Reuters) - The FAA lifted a nationwide ground stop on Friday after a communications failure at air traffic control centres caused chaos at US airports and triggered the longest shutdown since the September 11, 2001, attacks.
Transportation Secretary Sean Duffy said US airspace reopened at 8:15 p.m. Eastern Time (0115 GMT), but warned that departures would resume gradually and it would take time for airlines to restore normal operations.
"It's going to be slow," Duffy told reporters at the White House.
By 11:30 p.m., nearly 10,000 flights had been cancelled, including more than 2,200 each at Delta Air Lines and American Airlines, and 1,800 at United Airlines, according to Flightradar24. The plane-tracking website said some aircraft at major airports had waited more than five hours for a gate.
The four-hour nationwide grounding could disrupt airline schedules for days, aviation analysts said.
Duffy said tens of thousands of passengers were stranded at airports around the country. Duffy said he and Homeland Security Secretary Markwayne Mullin had met with President Donald Trump in the Oval Office to discuss the outage.
The failure is the latest and most dramatic sign of strain on a US air traffic control system beset by aging technology, equipment and communications problems and a shortage of several thousand controllers.
Duffy said the trouble began at 3:36 p.m., when air traffic control centers experienced instability in radar and communications systems.
"Our switches, our routers actually got overloaded with data and they started to give us inconsistencies in the data from those routers and because of that we shut the system down," Duffy said, adding that at no stage did they completely lose radar or communications and they were able to safely land thousands of planes.
Duffy said the immediate problem had been fixed and that flying was safe, but warned that a broader overhaul of the aging air traffic control system was needed to prevent similar failures.
