Single faulty router triggers nationwide US aviation shutdown, officials say

A massive, near five-hour shutdown of the United States aviation system that has disrupted more than 20,000 flights since Friday may have resulted from a single router installed by government contractor L3Harris, federal officials said.

The incident marks the latest breakdown within the Federal Aviation Administration's (FAA) ageing air traffic control telecommunications infrastructure, underscoring ongoing difficulties in overhauling legacy equipment whilst keeping active communications operational.

"This was an FAA system that didn't meet the moment," Transportation Secretary Sean Duffy said on Saturday.

Duffy stated that L3Harris was conducting scheduled maintenance on Friday to transition lines from legacy copper wiring to optical fibre in at least one remote facility, with officials confirming potential issues involving routers installed in Arkansas and Texas.

Network overload

"We're working to determine whether we had incompetence, meaning was it user error or installer error from L3Harris, or did they install a faulty router? We haven't determined what the fault was," Duffy said.

The newly installed hardware began flooding connected equipment with upwards of 1,000 connection requests every four to five seconds.

The resulting overload affected 17 of the FAA's 22 en route centres nationwide, generating severe data instability between facilities, radar installations, and aircraft, which forced regulators to order a nationwide ground stop.

The FAA spends $1 billion annually maintaining copper systems.

While communications channels remained open, data transmission faltered.

Duffy observed that the routers scheduled for replacement are roughly 25 years old and originally due for retirement in 2006.

L3Harris said it is actively "supporting the FAA in its investigation to understand the conditions that led to the Nov. 13 ground stop", noting it has finished over 70 percent of the planned airspace conversion to fibre optics.

Systemic vulnerabilities across aging network

Small mishaps have repeatedly hobbled US aviation.

In 2023, an engineer inadvertently deleted files, triggering a 90-minute shutdown that affected 11,000 flights in the first nationwide ground stop since September 11, 2001.

Although Congress granted the FAA $12.5 billion for system upgrades, Duffy has requested an additional $50 billion.

The agency still relies on vintage computers, parts sourced from online marketplaces, and only recently scheduled the phasing out of 1980s floppy disks by late 2028.

TRT World & Agencies — TRT World & Agencies

Photo: AP