In brief

• The FAA's nationwide ground stop on Friday is linked by Transportation Secretary Sean Duffy to maintenance work at a remote facility, where copper wire was being replaced with fiber optic cable.
• According to Duffy, a router involved in the upgrade overloaded a critical communication system, and the cause has not yet been confirmed.
• Officials said there was no cyberattack, and Duffy has called for $50 billion to replace aging air traffic control equipment.

Upgrade work linked to the shutdown

Transportation Secretary Sean Duffy said on Saturday that the Federal Aviation Administration's nationwide ground stop was linked to maintenance at a remote FAA facility, where copper wire was being replaced with fiber optic cable (FAA telecom problems that triggered the ground stop were so alarming the White House situation room and national security apparatus went into action – Fortune) (Transportation secretary blames ‘routine’ equipment upgrade for grounding flights nationwide – TechCrunch) (Work to replace old copper wire led to the FAA’s ground stop – The Verge). The work was carried out by L3Harris, a long-standing FAA contractor. Duffy described it as routine and said the copper line was being retired, which made the switch necessary, according to his account (Copper wire upgrade caused nationwide flight suspension, US transport secretary says – BBC News).

How the failure spread

That prompted the FAA to halt flights for safety reasons. Once the faulty location was isolated and taken offline, the network resumed normal operation, Duffy said. He also said the routers in these facilities dated to 2001 (FAA blames Friday's ground stop on 'equipment issue' during telecoms network upgrade – NPR).

Investigation and cyberattack questions

FAA Administrator Bryan Bedford said the agency had concluded the event was not a cyber issue. The White House situation room and national security agencies were briefly activated, and the FBI took part in the response (Washington atribuye el parón aéreo a un problema con un nuevo cableado de fibra óptica – EL PAÍS). Officials said they had seen no online signs of hacking. Duffy said it was not yet clear whether the cause was faulty hardware, a misconfigured router or contractor error.

Scale of the disruption

The FAA lifted the ground stop after several hours, and the disruption was expected to last for days (US lifts nationwide ground stop for airports hours after halting all departures – DW).

Funding request

Duffy said the government needs $50 billion to replace equipment and software dating back to the 1980s, and urged Congress to approve the money (Trump's transportation chief demands $50 billion to prevent another huge FAA fiasco – Business Insider).