Transportation secretary still doesn’t totally rule out that a cyberattack may have hit the FAA, and the FBI is assisting the probe

The Transportation Secretary remains open to the possibility of a cyberattack causing the nationwide ground stop of air traffic, despite initial indications to the contrary. Homeland Security Secretary Markwayne Mullin stated on Friday night that "it doesn’t appear" that a cyberattack was involved, though he acknowledged that "there’s nothing certain right now."

Transportation Secretary Sean Duffy expressed confidence on Sunday that foul play wasn’t involved, adding that the FBI and other intelligence agencies were on a call with the "intelligence partners" following the FAA’s communication problems. The investigation has focused on a copper-wire line being upgraded to fiber-optic cable by contractor L3Harris, which caused routers to receive over 1,000 connection attempts every four to five seconds, disrupting radar feeds and prompting the ground stop.

An L3Harris spokesperson stated that the company has been modernizing the communications infrastructure for the National Airspace System alongside the FAA, and that they have completed over 70% of the conversion. However, the exact cause of the disruption remains under investigation.