Transportation Secretary Sean Duffy has named the trigger for the nationwide US ground stop. He says it began while contractor L3Harris Technologies was switching telecoms lines from copper wire to fibre at a remote FAA site.
At a briefing on Saturday 14 November, Duffy said the router being replaced began flooding other routers with "over 1,000 connection attempts every four to five seconds", ABC News reports. He said this happened "either through contractor error or a faulty piece of equipment". Officials have not said which.
FAA Administrator Bryan Bedford said the logon attempts overwhelmed one set of routers at an en route facility. That facility switched to backups at other en route facilities, "and it propagated from there". He said: "None of the facilities actually went dark", according to CNN.
Duffy said people will be held "accountable" and that he is "stuck" with L3Harris, which owns the FAA's legacy telecoms network. "We need L3Harris or whoever provided that router to us to do a better job," he said. L3Harris had not responded to CNN's request for comment.
The on-record account broadly bears out the earlier CBS News report, citing sources, that a network update caused a crash. On Friday Duffy had blamed overloaded old routers without naming a trigger.