Officials Pin U.S. Ground Stop on Router Upgrade, Press Contractor L3Harris

Federal officials have ruled out a cyberattack as the cause of Friday's nationwide ground stop and pointed instead to a routine swap of communications routers, according to Al Jazeera and Newsweek. Transportation Secretary Sean Duffy has placed the focus on contractor L3Harris, which has not accepted responsibility, and officials say the exact fault has not been determined.

The disruption continued Saturday. Al Jazeera reported that more than 5,000 U.S. flights were canceled that day, after more than 9,000 were scrapped on Friday.

What officials say went wrong

The Federal Aviation Administration ordered the ground stop at 3:54 p.m. Eastern on Friday, citing a telecommunications outage affecting air route traffic control centers. It was lifted at 8:15 p.m., according to Al Jazeera.

Duffy said L3Harris was replacing old copper wire with fiber optic lines at a remote location when a router there began overloading the air traffic control system. He said it produced 1,000 connection attempts every four to five seconds. Communications at 17 of the FAA's 22 en route centers were affected. Officials could not immediately find the source, so they shut down the airspace, Duffy said.

The Professional Aviation Safety Specialists union said the problem was limited to two routers updated Friday. An official told Reuters the routers were believed to be in Arkansas and Texas. The union said its technicians were not involved in the work, and an FAA official said the agency did a safety assessment beforehand.

White House officials had met in the Situation Room amid fears of a cyberattack. Duffy said systems came back once the work at that location was isolated, so he does not believe it was a cyber incident. FAA Administrator Bryan Bedford said at Saturday's news conference that the agency sees no evidence of anything nefarious or AI-related.

Duffy's case against the contractor

Duffy said investigators are weighing whether L3Harris made an installation error or installed a faulty router, and that the fault has not been determined. He said the company, which he described as having done decades of FAA work, “didn't meet the moment.”

He also said the company owns the network and is the prime contractor, so the government cannot simply go elsewhere. He said officials intend to hold people accountable.

L3Harris's response

L3Harris said in a statement that it is supporting the FAA's investigation into the conditions behind the Nov. 13 ground stop and takes the impact on travelers, airlines and air traffic operations seriously. It told Al Jazeera it has worked in close coordination with the FAA and that safety and reliability are its highest priorities.

The company said it has finished more than 70 percent of the planned conversion from legacy copper to fiber optic. Newsweek reported that L3Harris, based in Melbourne, Florida, has handled key parts of the FAA Telecommunications Infrastructure for more than two decades. That network supports about 45,000 daily flights and links more than 4,400 FAA facilities. Newsweek also noted that the company's website claims it can upgrade systems without disrupting air traffic.

Why it matters for travelers and the system

Travelers face lingering fallout even though the stoppage is over. Airlines and airports were still working through backlogs and delays on Saturday, and cancellations ran into the thousands for a second day.

The episode has also revived the debate over aging air traffic control technology. Duffy renewed his call for Congress to fund upgrades and warned that a similar incident could happen again without them. Al Jazeera reported he is now seeking $50 billion, up from an earlier $30 billion request, after Congress approved $12.5 billion last year. Newsweek reported that President Donald Trump has requested $30.1 billion.

What happens next

The investigation is continuing, and officials have made no final determination on the cause. The FAA said it is doing additional testing with L3Harris. The question of whether human error or faulty equipment was responsible remains open.

Earlier on Around Prague: FAA Ground Stop Is Over: What Caused the Nationwide Outage and What It Means for Your Flight

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Around Prague, based on reporting by Al Jazeera, Newsweek