FAA ground stop live updates: Duffy blames 'overloaded' routers; thousands of flights canceled

Transportation Secretary Sean Duffy said that "inconsistency" in data from routers in the air traffic control system led to the FAA issuing a nationwide ground stop Friday.

At 3:36 p.m, "we experienced instability for our radar and our communications in our centers and our TRACONs across the country," he said, referring to Terminal Radar Approach Control facilities.

Duffy described an "incredibly old air traffic control system" that uses analog telecom.

"Our switches, our routers, actually got overloaded with data ... and started to give us inconsistency in the data from those routers. And because of that, we shut the system down," he said.

Homeland Security Secretary Markwayne Mullin reiterated that there was "no cyberattack" at the top of a press briefing Friday on the ground stop.

"I just want to reiterate this: The public was never at danger through this process. There was never any lives at risk. There was no flights at risk," he said.

The FAA said the nationwide ground stop is over, after more than four hours.

Transportation Secretary Sean Duffy and Homeland Security Secretary Markwayne Mullin will address reporters in the White House Briefing Room shortly regarding the FAA ground stop.