 The National Transportation Safety Board determines that the probable cause of this accident was the flight crew members ' failure to use available <unk> and aids to identify the airplane 's location on the airport surface during taxi and their failure to cross @-@ check and verify that the airplane was on the correct runway before takeoff . <unk> to the accident were the flight crew 's <unk> conversations during taxi , which resulted in a loss of positional awareness and the Federal Aviation Administration 's failure to require that all runway <unk> be authorized only by specific air traffic control clearances . 
