What was found
CONTINENTAL SUPPLIED, UNDER WARRANTY, A NEW REPLACEMENT CRANKSHAFT ASSEMBLY P/N: 649900 S/N: N23BA108 (8130-3 DATED 02/JUN/2023) TO REPLACE A PREVIOUSLY SUPPLIED NEW CRANKSHAFT ASSEMBLY. THE S/N: N23BA108 CRANKSHAFT (#2) WAS SUPPLIED BY CMI BECAUSE IT WAS FOUND (DURING A PROP STRIKE INSPECTION) THAT S/N: N22EA121 CRANKSHAFT (#1) HAD PROP FLANGE PLATING WAS COMING OFF AND SOME RUST PITS WERE FOUND IN THE TRANSFER COLLAR AREA AFTER 9.8HRS IN SERVICE [FOUR MONTHS SINCE OVERHAUL OF THE ENGINE]. THE REPLACEMENT S/N: N23BA108 CRANKSHAFT (#2) WAS INSTALLED DURING A PROP STRIKE INSPECTION OF THE ENGINE DURING JUNE 2023. 4HRS FLIGHT TIME AFTER INSTALLATION OF THE REPAIRED ENGINE ON 14/JUL/2023, BECAUSE OF AN ALTERNATOR FAILURE, THE CUSTOMER NOTICED HEAVY PITTING ON THE CRANKSHAFT (#2) IN THE TRANSFER COLLAR AREA AND ON THE ALTERNATOR DRIVE GEAR. ON 08/07/2023 THE SAME IA, MIKE KINGERSKY, THAT REPORTED THE SUBMITTED ISSUE ABOVE, FOUND SIMILAR CRANKSHAFT RUST ON ANOTHER IO-550-N(1) S/N: 685824 ENGINE THAT WAS OVERHAULED BY MIDWEST AERONAUTICAL SERVICE 02/13/2018, WHEN REPLACING AN ALTERNATOR.