Two pilots asked about safety ; video of the conversation released at safety hearing . NTSB investigator in charge Dan Bower said he has found no indication that the plane had mechanical problems . Pilot fatigue one of the hottest issues in commercial aviation ; cargo pilots want one safety standard for all . The National Transportation Safety Board did not find any mechanical problems with Airbus jet . Aircraft crashed in August just short of Birmingham in Alabama ; both pilots killed .
Two pilots asked about safety ; video of the conversation released at safety hearing . Pilot fatigue one of the hottest issues in commercial aviation ; cargo pilots want one safety standard for all . The National Transportation Safety Board did not find any mechanical problems with Airbus jet . Aircraft crashed in August just short of Birmingham in Alabama ; both pilots killed .