FAA Rebuild Overloaded the Network It Is Replacing, Mullin Says

The two men who explained Friday night's nationwide ground stop didn't tell the same story. Transportation Secretary Sean Duffy blamed the old system: switches and routers on the FAA's analog telecom network, much of it running over 1980s copper lines, got overloaded with data and started feeding controllers inconsistent radar and radio information. Homeland Security Secretary Markwayne Mullin, standing beside him at the White House, pointed at the new system going in. The FAA, he said, had been putting patches into the system and installing new equipment, and that new equipment “was overwhelming the older system.”

That difference matters, because it decides what Friday was. If the old network simply failed under an ordinary load, the fix is the one already underway: replace it faster. If the replacement work itself strained the legacy gear past its limit, then every week of the rebuild carries the same risk until the old system is gone — and the rebuild has years left to run.

The network is, by the government's own count, halfway through surgery. The FAA Telecommunications Infrastructure — FTI, the private network linking more than 4,400 FAA sites and carrying voice, radar and data between them — runs on time-division multiplexing, a technology rooted in the 1960s, and it's being rebuilt while it operates. As of May, 2,560 of 5,170 legacy copper lines had been replaced with fiber, according to a September review by the Government Accountability Office. The same review found the FAA had never built an integrated master schedule for the rebuild's first phase, and agency officials told auditors that swapping out 450 voice switches is the riskiest part of it.

No formal cause has been determined. CBS News has reported, citing sources, that an update to the network forced a reboot and a crash — an account that doesn't match the overload explanation and that neither the FAA nor L3Harris, the company that runs FTI as a managed service, has reconciled publicly. L3Harris has issued no statement. What officials did rule out Friday night was an attack: Mullin said investigators had seen zero evidence of a cyberattack, and the FBI doesn't believe criminal activity was behind the failure, according to a Bloomberg report citing an official familiar with the matter.

The funding fight started before the briefing ended. Congress appropriated $12.5 billion in July 2025, in the One Big Beautiful Bill Act, to begin the modernization, and Duffy said that money is being spent. In September he asked Congress for $30 billion more. On Friday night he raised the number in public: “The president has asked for $30 billion. I want $50 billion.” He argued against doing the job in pieces — “Let's not do a patchwork, a fix to a system that's critical for every single family” — and said the more than $15 billion handed to the FAA over the past 25 years had produced, in his words, barely anything.

The blame didn't land unanswered. Former Transportation Secretary Pete Buttigieg pushed back on suggestions that the previous administration had neglected the system — “We did a lot to upgrade the system” — and demanded clearer answers about what actually caused Friday's failure. That argument, over who let the system get this old, is now attached to a $50 billion question: whether Congress pays to finish the rebuild at the speed Duffy wants.

For travelers, the immediate bill is still arriving. Duffy warned Friday night that restoring normal operations would take time, with delays rolling into the weekend after more than 11,000 flights were delayed and 2,700 canceled on Friday. For the FAA, the harder problem doesn't have a funding line yet: until investigators say what actually overloaded the switches, the agency can't say whether Friday was the old system dying on schedule — or the rebuild leaning too hard on a network that has to hold until the day it's switched off.