As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) HIGH PITCH NOISE SOUND FROM ENGINE COMPARTMENT DURING LOCAL FLIGHT. ALL INSTRUMENT INDICATIONS WERE OK, NO VIBRATIONS. AFTER LANDING ACFT WAS CHECKED AND DURING RUN UPS, ALL INDICATIONS WERE OK, INCLUDING MAGNETO DROPS. RT MAGNETO REMOVED AND MAGNETO SHAFT WAS VERY ROUGH TO TURN. RT MAGNETO REPLACED AND ACFT CHECKED AT RUN UP AND FOUND OK (UNUSAL NOISE DISAPEARED). MAGNETO SENT TO MFG FOR INVESTIGATION AND WARRANTY.