--- title: "FAA's preliminary probe names 2001-2006 Cisco routers in Friday's ground stop" description: "The FAA's preliminary investigation points to two-decade-old Cisco routers, while Transportation Secretary Sean Duffy probes contractor L3Harris for incompetence. Whichever way the root cause lands decides who carries the blame and who gets the $30 billion modernization bill in Congress." publisher: "The Inference" section: "Policy & Labor" published: 2026-11-15T16:13:33.970Z modified: 2026-11-15T16:13:33.970Z canonical: https://theinference.org/article/faa-s-preliminary-probe-names-2001-2006-cisco-routers-in-friday-s-ground-stop language: en keywords: "FAA, Cisco, L3Harris, Air Traffic Control, Network Infrastructure" --- # FAA's preliminary probe names 2001-2006 Cisco routers in Friday's ground stop > The FAA's preliminary investigation points to two-decade-old Cisco routers, while Transportation Secretary Sean Duffy probes contractor L3Harris for incompetence. Whichever way the root cause lands decides who carries the blame and who gets the $30 billion modernization bill in Congress. On November 13 a communications failure at the Federal Aviation Administration, which runs US air traffic control, forced a nationwide ground stop that lasted more than four hours [2][3]. Airlines canceled over 8,200 flights on Friday and more than 3,000 on Saturday as they cleared the backlog [2][3]. [The FAA's preliminary investigation](https://news.ycombinator.com/item?id=50500721) now points to a specific piece of hardware: [Cisco](https://theinference.org/markets/companies/cisco) 600-series routers, built between 2001 and 2006, that were overwhelmed and fed out-of-sync data packets into the air traffic control system [1]. Three officials are telling three different stories about why, and the gap between them decides where both blame and replacement money go. ## The FAA's own finding points at old Cisco gear, not the contractor Transportation Secretary Sean Duffy told reporters on Saturday that [L3Harris](https://theinference.org/markets/companies/l3harris), the FAA's longtime communications contractor, was [upgrading copper wire to fiber at a remote site](https://techcrunch.com/2026/11/14/transportation-secretary-blames-routine-equipment-upgrade-for-grounding-flights-nationwide/) when a router flooded a critical system [2]. He is probing whether it was "incompetence," meaning installation error or a faulty router [2]. The same day, CBS News reported, citing senior government sources, that the FAA believes the failure was limited to the two-decade-old Cisco routers, that the faulty equipment has been identified and isolated, and that sources are receiving conflicting information about the cause [1]. Homeland Security Secretary Markwayne Mullin offered a third account: new security patches overwhelmed the older system [1]. [No official root cause has been announced as of November 14](https://securityboulevard.com/2026/11/daily-ot-security-news-november-14-2026/) [3]. ## L3Harris carries the headline risk; the hardware carries the technical one [L3Harris says it is cooperating with the investigation](https://seekingalpha.com/news/4672774-l3harris-addresses-ground-stop) and confirmed it is about 70% of the way through the planned copper-to-fiber upgrade of controller communications [4]. The routers the FAA's finding names, though, are a Cisco line manufactured two decades ago, well past end of life, inside a network the government is only now converting [1][4]. Duffy has said a root cause analysis is under way [2], and which way it lands shapes both the politics and the procurement. *Chart: **The disruption outlived the four-hour ground stop** Column chart: 8,200 flights canceled Friday, 8,000 delayed Friday, 3,000 canceled Saturday, showing the disruption outlasting the four-hour ground stop.* *Flights canceled and delayed around the November 13, 2026 nationwide FAA ground stop. Saturday's cancellations, counted as airlines cleared the backlog, came to more than a third of Friday's. Sources [2][3]. [2][3]* ## The $30 billion decision sits with Congress The administration has [asked Congress for $30 billion in additional aviation funding](https://theinference.org/article/the-faa-switched-on-875m-of-ai-and-24-hours-later-asked-for-30b-more), and Duffy has warned that more disruptions will follow without an overhaul [3]. An FAA that just watched legacy routers ground the country has a stronger case for that money, and a modernization program of that size is largely a networking procurement. [Our November 4 piece](https://theinference.org/article/cisco-s-6-billion-ai-backlog-comes-due-on-november-12-at-three-points-of-margin) argued Cisco's commercial position rests on whether its backlog converts at current margins; this failure makes the government's own aging Cisco estate the test case for that renewal cycle [5]. The sharper trading risk this week is L3Harris, whose modernization work is the target of Duffy's probe while the FAA's technical finding points away from it. Watch the root cause analysis: if it lands on installation error, L3Harris keeps the risk; if it lands on legacy hardware, the $30 billion ask gets easier to pass, and whoever replaces that network does the work that matters. ## Takeaway Three officials are telling three stories about why Friday's ground stop happened, and the root cause analysis decides whether L3Harris or two-decade-old Cisco routers take the blame, and whether Congress's $30 billion networking bill gets easier to pass. ## Sources 1. [CBS News reporting via Hacker News thread, 'Duffy Probing Possible L3Harris Incompetence in FAA Meltdown', November 2026](https://news.ycombinator.com/item?id=50500721) 2. [TechCrunch, 'Transportation secretary blames routine equipment upgrade for grounding flights nationwide', 14 November 2026](https://techcrunch.com/2026/11/14/transportation-secretary-blames-routine-equipment-upgrade-for-grounding-flights-nationwide/) 3. [Security Boulevard, 'Daily OT Security News: November 14, 2026'](https://securityboulevard.com/2026/11/daily-ot-security-news-november-14-2026/) 4. [Seeking Alpha, 'L3Harris addresses ground stop', 14 November 2026](https://seekingalpha.com/news/4672774-l3harris-addresses-ground-stop) 5. [The Inference, 'Cisco's $6 billion AI backlog comes due on November 12, at three points of margin', 4 November 2026](https://theinference.com/article/cisco-s-6-billion-ai-backlog-comes-due-on-november-12-at-three-points-of-margin) --- FAA's preliminary probe names 2001-2006 Cisco routers in Friday's ground stop — The Inference. Canonical: https://theinference.org/article/faa-s-preliminary-probe-names-2001-2006-cisco-routers-in-friday-s-ground-stop