WATCH LIVE: Sean Duffy and Markwayne Mullin brief media on FAA ground stop

Transportation Secretary Sean Duffy and Homeland Security Secretary Markwayne Mullin will hold a press conference Friday evening at the White House to discuss the Federal Aviation Administration issuing a ground stop earlier in the day.FAA IMPOSES NATIONWIDE GROUND STOP ON ALL FLIGHTS Recommended Stories The FAA halted all flight departures nationwide Friday afternoon due to a “rolling frequency outage” affecting facilities that monitor planes in the air.The cause remained unclear later in the evening, and Mullin said investigators were looking into it, but suggested that a telecommunications issue caused the disruption.