What was found
DURING INSP C/W AD 91-14-22 AND LYC SB 475 REV A, NO DAMAGE FOUND TO CRANKSHAFT COUNTERBORE RECESS, ALIGNMENT DOWEL, RETAINING BOLTS AND THREADS. UPON INSP OF CRANKSHAFT GEAR TEETH, SEVERAL WERE FOUND TO HAVE LINEAR PTTING WHICH APPEARED TO BE CAUSED BY PLATING BREAKDOWN DEFECTS RESEMBLING FRETTING/SPALLING. NO CRITERIA EXISTED IN BODY OF AD, MFG O/H MANUAL, OR SB TO IDENTIFY SERVICEABLE LIMITS FOR DAMAGE FOUND ON TEETH, SO GEAR REPLACED. IT NOTE: THIS ENGINE MAINTAINED USING 50-HR OIL CHANGES/SAMPLE INTERVALS WITH NO EVIDENCE OF INTERNAL PROBLEMS TO THIS POINT. RECOMMEND ADDITIONAL CRITERIA BE ADDED TO SUPPORT PARA (A) OF AD, SO A/W OF GEAR, SHOULD ANY DAMAGE BE FOUND, CAN BE DETERMINED. (X)