What was found
THE ENGINE (PT6A-60A, P/N 3102700-01 S/N PCE-PK0793) WAS UNDERGOING A REPAIR I.A.W. P&WC LIGHT OVERHAUL CRITERIA AND WAS TESTED AT EURAVIA. THE ENGINE SUBSEQUENTLY PASSED TEST AND AS PER EURAVIA STANDARD PRACTICE A BORESCOPE POST-TEST WAS PERFORMED. DURING THE BORESCOPE PROCESS A CRACK INDICATION WAS NOTED AT THE COMPRESSOR TURBINE (CT) BLADE TIP AND THE ENGINE WAS SEPARATED AT THE C FLANGE TO INVESTIGATE. THE CT DISK WAS REMOVED FOR VISUAL INSPECTION, AND A MINOR TIP RUB, WHICH WAS ACCEPTABLE TO P&WC MAINTENANCE CRITERIA, WAS REMOVED FROM THE SHROUD SEGMENTS. DURING THE INSPECTION OF THE ASSEMBLED CT DISC, AN ADDITIONAL FINDING OF MISSING MATERIAL WAS FOUND ON ONE BLADE. FURTHER INVESTIGATION REVEALED THE MATERIAL MISSING WAS THE ENTIRE THICKNESS OF THE CONVEX SIDE, TOWARD THE TIP AND AT THE GREATEST SURFACE RADIUS. MISSING MATERIAL APPEARS TO BE ON A CT BLADE WITH A THINNER MATERIAL CROSS SECTION THAN THE REMAINDER OF THE SET. THE MISSING MATERIAL COULD NOT BE SEEN VIA STANDARD BORESCOPE PROCEDURE AND WAS ONLY FOUND AS PART OF THE DETAIL INSPECTION ON REMOVAL. THE INITIAL SUSPECT CT BLADE CRACK INDICATION AT THE TIP, FOUND DURING POST-TEST BORESCOPE, WAS A FALSE INDICATION DUE TO THE DESIGN OF THE PMA BLADES. PREVIOUS HISTORY SHOWS THE CT BLADE P/N E3121111-01 WAS INSTALLED AT OVERHAUL IN NEW CONDITION (FORM ONE REF MP-22-0009). THE CT DISC ASSEMBLY HAS HAD THE 1 OFF DAMAGED CT BLADE REMOVED AND THE REMAINDER OF THE ASSEMBLY PLACED IN QUARANTINE.