Officials from the Department of Homeland Security and FAA have attributed the November 13, 2026, nationwide air traffic control ground stop to a telecommunications failure in the legacy FAA Telecommunications Infrastructure network managed by L3Harris Technologies. Aging switches and routers became overloaded with data during system patches and upgrades, producing radar and communications inconsistencies without any signs of malicious intrusion. Secretary Markwayne Mullin reported zero evidence of a cyberattack or criminal activity, with the FBI focusing instead on a possible software update trigger. This rapid official consensus, consistent with the 2023 NOTAM database incident, underpins the 96.3% market-implied probability for “No.” Ongoing NSA and DHS reviews could still surface new findings on vulnerabilities in the aging infrastructure or contractor processes.