The router fault behind the nationwide US ground stop disrupted communications with aircraft and some radar feeds, Transportation Secretary Sean Duffy said at his briefing on Saturday 14 November, Bloomberg reports.
Duffy said systems came back once the FAA isolated the work at the remote site, where a router was being switched from copper to fibre.
He said the router sent more than 1,000 connection attempts to other routers every four to five seconds. CBS News and Scripps News report the same rate. CNBC gives it as "roughly every five seconds".
Duffy said investigators have not yet established whether the cause was an installation error or a defective router, according to Investing.com.