US ground stop caused by aging equipment, no evidence of cyberattack, Transportation Sec. says

US Transportation Secretary Sean Duffy said Friday that the nationwide ground stop put in place earlier in the day was triggered by aging air traffic control equipment that became overloaded with data, causing disruptions to radar information and communications with aircraft."What we have is an incredibly old air traffic control system," Duffy said, explaining that outdated analog telecommunications equipment, including switches and routers, began producing inconsistent data.More than 3,500 aircraft were airborne when the ground stop was imposed. Duffy said that, at the time of his latest update, fewer than 400 remained in the air as controllers worked to bring flights safely to their destinations.Homeland Security Secretary Markwayne Mullin said investigators had found no evidence of a cyberattack, although the investigation was continuing."There is actually no cyberattack. We're still working through that process. Our teams are working," Mullin said.Mullin said multiple federal agencies, including the Department of War, the Cybersecurity and Infrastructure Security Agency (CISA), the National Security Agency (NSA), and components of the Department of Homeland Security, are investigating the incident."There is nothing that indicates it yet," Mullin said. "There's no chatter. We haven't seen any footprints, as you would say, or identifications of people that got into the system."He noted that cyberattacks are often accompanied by claims of responsibility, but no such claims have emerged.Duffy calls for federal…