What was found
PROPELLER, S/N HL233, WAS RETURNED FOR VIBRATION. AFTER DISASSEMBLY, INSPECTION REVEALED ONE BROKEN A-3204-1 PRELOAD SET SCREW. THE SCREW WAS BROKEN INTO TWO PIECES WITH THE B-3368 LOCKNUT STILL ATTACHED TO THE INBOARD SECTION OF THE BROKEN A-3204-1 SCREW. THE SCREW WAS REMOVED, SENT TO HARTZELL ENGINEERING FOR EVALUATION AND REPLACED WITH NEW. THE C-6066-1 PRELOAD PLATE THREAD WAS DAMAGED, BUT WITHIN ACCEPTABLE LIMITS AND THE PLATE WAS REPAIRED AND RETURNED TO SERVICE.