WASHINGTON: US officials are investigating whether an L3Harris-installed router caused Friday’s nationwide aviation shutdown, which lasted nearly five hours and disrupted more than 20,000 flights.
Transportation Secretary Sean Duffy said Saturday that investigators were examining possible equipment defects or installation errors during a telecommunications upgrade.
The Federal Aviation Administration (FAA) grounded departures nationwide after network instability affected 17 of its 22 en route air traffic control centres. Officials could not immediately identify the cause of the disruption.
Duffy said L3Harris had been replacing ageing copper telecommunications lines with fibre-optic connections as part of routine maintenance. Officials identified possible router problems at facilities in Arkansas and Texas.
Investigators have not established whether faulty equipment or human error caused the failure. L3Harris acknowledged the disruption and confirmed it is cooperating with the FAA investigation.
Read: US Ground Stop Ends After Four-Hour Communications Outage
The company said it had completed more than 70% of the planned conversion to fibre-optic communications. Duffy explained that newly installed routers began sending more than 1,000 connection attempts every four to five seconds.
The resulting network overload disrupted data exchanges involving aircraft communications and radar systems. However, the FAA maintained that communications had not completely failed.
Instead, unstable data prevented controllers from relying on normal information flows. Duffy said some routers were approximately 25 years old and should have been replaced in 2006. “This was an FAA system that didn’t meet the moment,” he told reporters Saturday.
The FAA spends $1 billion annually maintaining its ageing copper telecommunications network. Congress has approved $12.5 billion for system upgrades, while Duffy has requested another $50 billion for aviation infrastructure.
The agency plans to replace outdated floppy disks at more than 400 air traffic control facilities by the end of 2028. Previous technical failures have disrupted flights in the US.
In 2023, a contractor accidentally deleted files, triggering a nationwide ground stop lasting 90 minutes. That disruption affected 11,000 flights.
Read: US Flight Cancellations Surge as Severe Weather Hits Airports
During September, a circuit failure in Philadelphia and a severed fibre-optic cable in New Jersey caused widespread delays across the northeastern United States.
Duffy said officials would reconsider when contractors perform maintenance at smaller facilities to reduce the risk of similar disruptions.
With additional input from Reuters
