What was found
THE PILOT REPORTED THE LH ALTERNATOR FAILURE LIGHT ILLUMINATED IN FLIGHT, WITH THE LH ALTERNATOR INDICATING NO ELECTRICAL OUTPUT. THE ALTERNATOR WAS INSTALLED ON 05/20/2025 AT AN AIRFRAME TOTAL TIME OF 4939.8 HOURS AND WAS REMOVED AS INOPERATIVE ON 05/14/2026. AT THE TIME OF REMOVAL, THE ALTERNATOR HAD ACCUMULATED APPROXIMATELY 544.2 HOURS IN SERVICE. DURING THE UNIT'S EVALUATION, WE WERE INFORMED THAT MATERIAL DESCRIBED AS RESEMBLING “ALUMINUM FOIL” WAS FOUND INTERNALLY. WE WERE ALSO ADVISED THAT IT APPEARED SOMETHING INSIDE THE ALTERNATOR MAY HAVE BEEN COMING APART INTERNALLY, AND THAT THIS WAS NOT SOMETHING NORMALLY SEEN.