FAA router failure triggered nationwide flight ground stop

The upgrade was carried out by L3Harris, a longtime Federal Aviation Administration contractor. Duffy described the work as routine and said the agency was trying to determine whether there had been user or installation error, or whether the router itself was faulty.

FAA acting CTO Rebecca Guy said the agency traced network instability to two locations generating about 1,000 connections every four to five seconds. The FAA disabled both sources, she said, stabilizing the network, and is conducting a root-cause analysis. FAA Administrator Bryan Bedford said there was “zero evidence” the incident was nefarious or related to artificial intelligence. The agency had announced an AI tool for air traffic controllers the day before; the controllers’ union said it had not been consulted on the system’s design.

Duffy has repeatedly called for Congress to provide more funding for aviation equipment upgrades. Asked why the work was done at 3 p.m. Friday rather than overnight, he said switchovers at major airports take place late at night, while work at remote sites happens during the day. He said the agency would reevaluate when such work is scheduled.

The incident was only the third nationwide ground stop of the 21st century. More than 8,200 flights were canceled Friday evening, according to aviation data firm Cirium, and at least 3,000 more were canceled Saturday after the stop was lifted. Asked earlier whether AI caused the disruption, Homeland Security Secretary Markwayne Mullin quipped, “We call it SI around here, remember? SI.”