What was found
PASSING FL280 LEFT ENGINE INSTRUMENTS RAPIDLY ROLLED BACK. FLIGHT ATTENDANT REPORTED LEFT ENGINE ON FIRE. LEFT ENGINE WAS SHUTDOWN. AIRCRAFT RETURNED TO LAX. *S/D* UPON ARRIVAL AT LAX FOUND METAL IN THE TAILPIPE DUE TO AN HPC FAILURE, THE FIRE WAS INTERNAL DUE TO THE FAILURE. THE ENGINE WAS REPLACED. SHOP FINDINGS WERE THAT A 10TH STAGE HPC STATOR HAD FAILED. THIS FAILURE IS A KNOWN MODE AND THIS EVENT IS STILL UNDER INVESTIGATION BY UA AND PWA.