Homeland Security Secretary Markwayne Mullin has suggested that new equipment and patches installed by the FAA overwhelmed the older air traffic control system. It is the first possible trigger for the nationwide ground stop offered on the record.
Speaking at Friday evening's White House briefing, Mullin said the new technology "was overwhelming the older system", according to the Irish Star. Axios reports that he said officials are looking into incompatibilities between older equipment and newer technology currently being installed.
Transportation Secretary Sean Duffy put the emphasis on the old hardware. "All of the new equipment that we put in, none of that went down," he said, as quoted by the Advocate. He told the briefing: "We have old, old switches, old routers. We use 1980s little copper lines."
The two accounts do not strictly contradict each other, since new kit could keep working while overloading the old. But the Advocate reports that Duffy did not establish whether the upgrades set off the failure, and neither official said which new technology Mullin meant. Duffy ruled out the SMART AI tool, saying it is not connected to the affected systems.
Duffy said instability in radar and communications systems began at around 3.36pm ET, before the 3.54pm ET ground stop, Fox Business reports.