What was found
(CAN) A/C CAME IN FOR OVERNIGHT WITH NO MAINT PROBLEMS REPORTED. DURING OVERNIGHT SERVICE CHECK, DAMAGE NOTED ON BYPASS DUCT & CORE ENGINE. INITIAL INSPECTION FOUND DAMAGE IN BPD (BYPASS DUCT) AFT LOOKING FWD. AT 9 TO 2 O'CLOCK POS FROM BPD STATOR VANES TO END OF BPD. MOSTLY INNER BPD FIBRE GLASS LINER HAD BURNT AWAY, EXPOSING BPD HONEYCOMB SECTIONS. ALSO HEAVY DAMAGE TO UPPER SPLITTER FAIRING & WIRE BUNDLE DAMAGE. FURTHER T/S UNABLE TO LOCATE SOURCE OF FIRE: OPENED UP UPPER COWLING & INSP 5TH & 8TH STAGE BLEED DUCTS FOR DAMAGE, EVERYTHING FOUND IN GOOD ORDER.