Officials said that the upgrade to antiquated communications equipment at a remote facility overloaded other parts of the national air traffic system.
The communications failures that prompted Federal Aviation Administration officials to issue a nationwide ground stop started when L3 Harris, a contractor managing the agency’s telecoms network, made a standard upgrade at a remote air traffic location, federal officials said Saturday.
The contractor was conducting work on Friday that was needed to replace aging analog copper wire with more modern fiber optic cable, Sean Duffy, the transportation secretary, told reporters. The “routine” task was being done at a location remote and small enough that officials assumed a Friday afternoon upgrade would pose no meaningful disruption to the air traffic, he said.
That presumption proved wrong, as the changeover from copper to fiber started flooding the system with levels of data it could not handle, triggering a cascade of communications failures across the air traffic facilities that manage the national air space. Officials, alarmed at the scope of the problems, decided to issue a rare nationwide ground stop for hours.
As of Saturday morning, administration officials still have not determined whether L3 Harris or shoddy equipment was at fault.
“What we’re working to determine was whether we had incompetence, meaning it was user error or installer error from L3 Harris, or did they install a faulty router?” Mr. Duffy told reporters. “We haven’t determined what the fault was.”
Representatives for L3 Harris did not immediately return email and phone requests for comment on Saturday.
