(AP) – The Federal Aviation Administration will investigate after a flight at Ronald Reagan Washington National Airport was instructed to cross a runway where another flight was starting its takeoff, the agency said. A JetBlue flight was starting its takeoff roll on runway 4 at the airport in Arlington, Virginia, just outside Washington, D.C., around 7:41 a.m. Thursday, when an air traffic controller instructed a Southwest Airlines flight to cross the same runway, the FAA said in a statement. The agency will investigate the event.