NTSB Probable Cause

THE AIRCRAFT ENTERED INTO AN UNCONTROLLED DESCENT. THE EXISTENCE OF A MOUNTAIN WAVE ALONG THE AIRCRAFT'S FLIGHT ROUTE, THE FAILURE OF THE CREW TO EVALUATE REPORTED WEATHER CONDITIONS ALONG THE FLIGHT ROUTE, THE CREWS ATTEMPT TO FLY INTO KNOWN ADVERSE WEATHER CONDITIONS, AND THE OVER CONFIDENCE OF THE CREW IN THE AIRCRAFT'S ABILITY WERE FACTORS IN THE ACCIDENT.