What was found
(CAN) WHILE CARRYING OUT A SCHEDULED HOT SECTION INSPECTION ON THE ABOVE ENGINE, IT WAS DISCOVERED THAT 2 NOZZLE SHEATHS WERE OF AN INCORRECT PART NR FOR THE MODEL OF ENGINE INSTALLED. THE PART NRS ARE BOTH FOR A PT6A-50 ENGINE. EVEN THOUGH WE OPERATE THIS MODEL OF ENGINE, OUR INVENTORY RECORDS DO NOT SHOW THIS PART EVER BEING ISSUED TO THIS ACFT. THERE IS A POSSIBILITY THAT THESE 2 SHEATHS HAD BEEN INSTALLED AT ENGINE OVERHAUL, T.S.O. 3522 HRS. 2 REPLACEMENT SHEATHS OF THE CORRECT PART NR WERE INSTALLED AND THE ENGINE RETURNED TO SERVICE.