‘Contractor error’ or ‘faulty’ router to blame for FAA ground stop: Duffy

U.S. Transportation Secretary Sean Duffy provided an update on the FAA nationwide ground stop, explaining that the action originated from a problem tied to a router involved in routine upgrades. The briefing described the issue as stemming from either contractor error or faulty equipment, and officials indicated the halt was aimed at safeguarding safety while investigators reviewed the root cause and its implications for air traffic operations.

AirLive relayed that investigators are focusing on a router being replaced during ongoing efforts to modernize the air traffic control network. According to Duffy, a router undergoing replacement by contractor L3Harris Technologies began malfunctioning and flooded other routers with excessive data traffic, destabilizing the system. Duffy stressed that the investigation is evaluating whether there was incompetence or a faulty piece of equipment, and he explicitly ruled out cyberattack or artificial intelligence anomalies as the cause.

The initial nationwide ground stop halted all departing flights across the United States for more than four hours, with about 50,000 flights scheduled on Friday and roughly 30,000 of those eventually able to depart before the stop took effect, as reported by AirLive and echoed by other outlets. The stoppage was described as an extraordinary safety measure designed to preserve safety while the system was reviewed.

CTV News summarized the FAA action as a nationwide, immediate ground stop affecting departing flights, with international arrivals to be handled on a case-by-case basis as the situation evolved. The coverage noted that the underlying issue described by Duffy was a communications-related problem within air route traffic control centers, and that the duration of the halt was not specified in the initial advisories.

Canadian outlets highlighted the broader ripple effects beyond the United States. Edmonton’s airport indicated seven upcoming U.S.-bound departures could be affected, and travelers were advised to check with their airlines. Montreal-Trudeau International Airport suspended flights to and from the United States as part of the broader disruption. Edmonton emphasized that the stop’s duration remained undetermined and that departures were being reviewed case by case, with CTV News tying these Canadian impacts to the U.S. action described by Duffy as a communications issue in air route traffic control centers.

USA Today and other outlets reported that the nationwide stop triggered cascading disruptions such as flight reroutings, delays, and cancellations as airlines and airports scrambled to normalize operations. The disruption prompted a concerted effort to replan schedules and manage the flow of air traffic once the system was deemed ready to resume normal operations.

Simple Flying offered a broad view of the event, noting that thousands of travelers were affected and that the grounding lasted several hours. It described the grounding as part of an extraordinary safety measure tied to broader issues in air-traffic-control operations and indicated that aircraft already in flight were permitted to continue under existing clearances, consistent with ATC Zero procedures, while departures were halted.

The Chicago area, including O’Hare International Airport, emerged as a notable carve-out in the nationwide pause, with departures held for a mid-afternoon window due to thunderstorms. FAA officials indicated the extension window could depend on evolving weather conditions, and this weather factor was cited by multiple outlets as a contributing element to the temporary scheduling adjustments in that region.

Overall, the incident was positioned as a two-phase national action: an immediate halt to new departures, followed by ongoing updates from the FAA as investigators pursued the root cause. The reporting consistently described the event as nationwide and immediate, with no publicly connected injuries or fatalities noted in the initial material, and with international arrivals being handled on a case-by-case basis as the situation evolved.