What was found
(CAN) UNUSUAL NOISE DURING START. PILOT REPORTED UNUSUAL NOISE DURING NR 1 ENGINE START, WHEN PROPELLER PITCH CHANGED FROM FEATHER TO UN-FEATHER POSITION. PILOT SHUTDOWN THE ENGINE. MECHANIC PERFORMED ENGINE RUN AND FOUND ENGINE SUFFERED SERIOUS VIBRATION WHEN NH REACHED 56-60 PERCENT. VISUAL INSPECTION FOUND PT2 STAGE WITH 1 BLADE FRACTURE AND OTHER BLADES DAMAGED. ENGINE LAST SHOP VISIT FOR HSI. ENGINE RETURNED BACK FOR ROOT CAUSE INVESTIGATION. TDR FINDINGS: LP IMPELLER RUBBING AND IMPACT DAMAGES ON HP IMPELLER. THE PT MODULE WILL BE INVESTIGATED TO IDENTIFY THE ROOT CAUSE OF THE BLADE FRACTURE.