An awkward exchange between two senior US officials has drawn attention to the work behind Friday’s nationwide FAA ground stop. A day later, Transportation Secretary Sean Duffy said investigators were examining a router fault during a contractor’s switch from copper to fibre telecommunications lines.
The apparent headshake and brief contact between Duffy and Homeland Security Secretary Markwayne Mullin at a White House briefing on 13 November 2026 have circulated widely online. However, the important development is not what either man may have been thinking. It is what their public explanations reveal about the FAA’s ageing communications system and an upgrade that was under way when it failed.
What did Mullin say at the White House?
During Friday night’s briefing, Mullin suggested that new equipment and patches being installed as the Federal Aviation Administration modernised its systems were overwhelming older technology. Duffy separately emphasised overloaded legacy switches and routers, saying the new equipment installed as part of the modernisation had not itself gone down.
Video of the briefing appears to show Duffy lowering his head, shaking it and making brief contact with Mullin as the DHS secretary talks. Social media publisher MeidasTouch characterised the moment as Mullin throwing Duffy ‘under the bus’. The footage does not establish what Duffy intended by the gestures, whether they were directed at Mullin or whether the two officials actually disagreed. Neither has publicly confirmed such an interpretation.
The two technical descriptions are not inherently incompatible. Equipment introduced during an upgrade could trigger instability in older parts of a network without the new equipment itself failing. The sequence of events and the location of the fault are what matter.
Saturday’s briefing: contractor work and a flood of connections
On Saturday 14 November, Duffy gave a more specific preliminary account at the Department of Transportation. He said a longstanding FAA contractor, L3Harris, had been carrying out routine maintenance at at least one remote FAA location, moving a telecommunications connection from ageing copper lines to fibre.
According to Duffy, a router involved in that work began flooding others in the air traffic control network with more than 1,000 connection attempts every four to five seconds. The resulting instability affected communications with aircraft and some radar feeds. Officials isolated the activity and restored operations.
Duffy said investigators had not determined whether the problem was caused by user or installation error or by faulty equipment. His public criticism of the contractor is therefore an allegation about a possible cause, not a concluded finding of fault against L3Harris. The Department of Transportation published his Saturday account. Reuters also reported the investigation and the role of L3Harris.
How did a routine upgrade become a nationwide disruption?
Friday’s disruption began around 3.36pm Eastern Time, according to Duffy, after controllers encountered inconsistent radar information and communications. The FAA imposed a nationwide departure ground stop while aircraft already flying were managed through safety procedures. The restriction was lifted at about 8.15pm Eastern Time, but airline cancellations continued into Saturday.
Reuters reported that communications problems affected 17 of the FAA’s 22 en-route control centres and disrupted more than 20,000 flights. Those wider disruption figures include delayed or cancelled services, not only flights directly stopped at departure. Duffy and FAA Administrator Bryan Bedford said the network had returned to full operations on Saturday, although airlines still faced a substantial recovery.
A single fault can have consequences far from where it occurs because controllers at different facilities depend on telecommunications links to communicate with aircraft and pass flights between sectors. It remains unclear why this particular event spread so widely, how backup arrangements performed and what checks were completed before the upgrade.
What is confirmed and what remains unknown?
- The ground stop and the technical instability happened on Friday 13 November, and the nationwide restriction was lifted that evening.
- Duffy has identified ongoing L3Harris copper-to-fibre work and unusually heavy router connection attempts as the current focus of the inquiry.
- The FAA has not published a final technical root-cause report establishing whether a contractor mistake, defective equipment or a wider design issue was responsible.
- Officials say they have found no evidence so far of a cyberattack or AI involvement. That is not a substitute for the final investigation.
- No verified evidence currently establishes that Duffy’s reaction during the briefing was a deliberate rebuke of Mullin.
The larger oversight question is how a critical national network could be disrupted during routine work. A September 2026 Government Accountability Office report had already highlighted planning and coordination risks in the FAA modernisation programme. That audit is relevant background, but it does not prove a connection to Friday’s outage.
Watch the Duffy and Mullin briefing
The full 13 November briefing is available from the White House video library, with a searchable transcript published by Roll Call Factba.se. The official White House recording is embedded below. Jump to approximately 14 minutes 36 seconds for Mullin’s comments about newer technology and the older system.
What happens next?
The next meaningful update will be a documented explanation of how the router behaved, what caused it to send repeated connections and why protections did not contain the disruption. That should include the contractor’s evidence, the FAA’s test and change records and any steps taken to prevent a recurrence.
For the wider timeline, read our report on the lifting of the ground stop and our separate examination of the FAA’s backup safeguards. Follow this story: FAA nationwide ground stop coverage.
Sources
- US Department of Transportation: Duffy’s 14 November briefing
- White House: 13 November video and Roll Call Factba.se transcript
- Reuters: FAA router investigation and national disruption, 14 November
- Associated Press: nationwide FAA ground stop and communications disruption
- Government Accountability Office: FAA modernisation audit, September 2026
