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Transportation Secretary Sean Duffy attributed the nationwide ground stop to work by contractor L3Harris Technologies at one remote Federal Aviation Administration facility where technicians were switching an outdated copper telecommunications line to fiber optic cable. The process caused a router to flood the broader air traffic control network with more than 1,000 connection attempts every four to five seconds, leading to inconsistent data, disrupted communications with aircraft and intermittent radar gaps. Duffy stated in a White House briefing that officials remain uncertain whether the failure stemmed from contractor error or a faulty router installed during the upgrade. Homeland Security Secretary Markwayne Mullin added at the same briefing that newer equipment being patched into the legacy system had overwhelmed its capacity.
The Federal Aviation Administration issued the ground stop shortly after 3:36 p.m. ET on November 13, 2026 and lifted it at 8:15 p.m. that evening, according to multiple administration accounts. FAA Administrator Bryan Bedford reported the following day that the system had returned to full operations, though he cautioned that residual effects would persist. Bedford told reporters the worst disruptions appeared behind schedule recovery teams while airlines worked to reposition aircraft and crews. The agency had already transitioned more than 70 percent of its copper lines to fiber as part of a multiyear modernization project intended to reduce outages and accommodate newer aircraft such as drones and eVTOLs.
Aviation data company FlightAware reported that more than 6,300 flights within, into or out of the United States were canceled on November 13 while another 9,500 experienced delays. The figures included disruptions to freight and mail services, with additional cancellations and delays exceeding 5,100 flights the following day. Industry estimates placed the number of affected passengers near 1.5 million as travelers sought alternative transport including Amtrak services. Officials acknowledged that full schedule normalization could require days or weeks.
Duffy described the underlying infrastructure as decades-old analog equipment including switches and routers reliant on 1980s-era copper lines that the department continues to sustain because they remain in service. The telecommunications network is managed by L3Harris, which Duffy identified as the FAA’s legacy provider for more than 20 years and the owner of the affected network. A CNN review of the briefing noted that newer FAA equipment already deployed elsewhere was unaffected by the outage. The incident marked the longest nationwide ground stop since the September 11, 2001 attacks.
Administration officials ruled out any connection to a separate international Microsoft outage that occurred days earlier, according to Mullin’s statements at the White House. Duffy urged Congress to approve between $30 billion and $50 billion in additional funding to accelerate infrastructure upgrades, framing the investment as essential to prevent recurrence. He emphasized that the modernization effort, which received $12.5 billion from Congress last year, has already replaced thousands of copper wires and upgraded radio systems but must continue at a faster pace.
Bedford indicated that investigators continue to map remaining copper connections requiring replacement while reviewing the precise sequence of events at the remote site. Duffy told reporters the work itself was straightforward and involved converting from time-division multiplexing to internet protocol. The secretary reiterated that safety considerations had dictated the immediate ground stop once communications instability appeared.
