Duffy and Homeland Security Secretary Markwayne Mullin said the outage was caused by older routers being overloaded with data. By Will Guisbond Transportation Secretary Sean Duffy called on Congress to authorize $50 billion in emergency funding to overhaul the US air traffic control system after a technical issue spawned the longest nationwide grounding in more than two decades. “This is an emergency,” Duffy said at a White House press conference on Friday.