As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE REPAIRING EXHAUST SYSTEM, FOUND DUCT COLLAPSED AND BADLY DETERIORATED. OLD DUCT APPEARED TO BE ORANGE SINGLE WALL SCAT HOSE. NEW DUCT WAS BLACK HEAVY DOUBLE WALLED AND BORE BEECH P/N NR I.D. ON OLD DUCT. REMOVED AND REPLACED DUCT.