What was found
THE FLIGHT CREW REPORTED THE PRIMARY PITCH TRIM FAILED ON SHORT FINAL WHEN FULLY CONFIGURED WITH THE AUTO PILOT. THE LANDING WAS UNEVENTFUL. THE MAINTENANCE VENDOR TROUBLESHOT AND FOUND THE TRIM ACTUATOR AND TRIM CONTROL BOX DEFECTIVE. THE PITCH TRIM ACTUATOR WAS REMOVED AND A REPAIRED ACTUATOR INSTALLED AND THE TRIM CONTROL BOX WAS REMOVED WITH A REPAIRED UNIT. OPS CHECKS WERE SATISFACTORY AND THE AIRCRAFT WAS RETURNED TO SERVICE. TRIM CONTROL BOX REMOVED P/N 6627401000-003 S/N D450 STAB ACTUATOR REMOVED P/N 6627401000-009 S/N B0596