THE IMPROPER INSTALLATION OF THE ELEVATOR CONTROL CABLES BY REPAIR FACILITY MAINTENANCE PERSONNEL, THE INSPECTOR'S INADEQUATE INSPECTION OF THE MAINTENANCE ACCOMPLISHED, AND HIS FAILURE TO FOLLOW DELINEATED PROCEDURES. AN ADDITIONAL CAUSE WAS THE INADEQUATE PREFLIGHT INSPECTION BY THE PILOT IN COMMAND, IN THAT HE FAILED TO CONFIRM CORRECT CONTROL SURFACE MOVEMENT AS REQUIRED BY THE PRE-UNMASTING CHECKLIST.