FAA Lifts Nationwide Ground Stop After Telecom Outage; Duffy Blames Ageing Air Traffic Control Systems

At 3:36 on the afternoon of the outage, radar and communications equipment at air traffic control centres and Terminal Radar Approach Control facilities across the United States began to behave unpredictably. Within a short time the Federal Aviation Administration imposed a nationwide ground stop, halting departures at airports around the country. It has since lifted that order, but not before thousands of flights were delayed or cancelled.

Transportation Secretary Sean Duffy laid out the sequence for reporters at a press briefing. Controllers, he said, started receiving inconsistent data from radars and inconsistent communication with aircraft. There are procedures for that situation, he said, and he credited the training of pilots and controllers. The ground stop was the result. He stressed that the country had not lost all of its telecom or all of its radar; the problem was instability, and the stop was ordered out of caution.

The numbers from the briefing show the scale of what controllers were managing. More than 3,500 aircraft were in the air when the order came, and Duffy said authorities coordinated their safe landing. By the time he spoke, fewer than 400 remained airborne. Medical evacuation flights, cargo carrying life-saving medicines and law enforcement operations were allowed to continue. The FAA confirmed that all flights were accounted for, and said international arrivals were being handled case by case.

Duffy pointed to the country's ageing equipment as the cause. The system relies on TDM telecom, which he described as analogue, and he said its switches and routers became overloaded with data. He corrected himself mid-sentence: they did not exactly go down, but began giving inconsistent data, and for that reason the system was shut down. Newer Internet Protocol switches installed under the Trump administration kept working through the incident, he said, while the older hardware faltered.

He used the moment to renew a request to Congress. The president, Duffy said, has spent the past year asking lawmakers to fully fund a brand-new air traffic control system. He argued against piecemeal repairs to a system that touches every family, and framed the issue as nonpartisan: not red, not blue, but American. "Give us the money to fix it," he said.

Homeland Security Secretary Markwayne Mullin addressed the question many travellers were asking online. He said there was no connection to Microsoft, referring to a separate disruption that some people had linked to the outage. So far, he said, officials had seen no cyberattack, though he added that the work of confirming that was still going on and teams were still examining it. Mullin said the administration had mobilised resources across agencies, and that the Federal Emergency Management Agency had opened its centres so stranded passengers would not miss essential medication.

The cost to travellers was large. FlightAware counted roughly 7,000 flights delayed or cancelled. Flightradar24 data showed thousands of aircraft heading toward US airports when the ground stop was announced. Airlines abroad felt it too: Air India posted on X that departures from US airports were affected and that its flights to and from the United States could see knock-on disruption. It told passengers to check flight status before leaving for the airport and said its teams were monitoring the situation.

Two things are worth watching. One is whether Congress acts on the funding request for a full rebuild of air traffic control. The other is the formal finding on the cause, since the overload explanation comes from Duffy's briefing while Mullin has said the examination of a possible cyber link was still in progress.