What was found
DURING START IN DCA, APU EXPERIENCED AN AUTO SHUTDOWN WITH SUBSEQUENT FIRE BOTTLE DISCHARGE. INSPECTED TAILCONE, APU AND ACCY COMPARTMENT IAW AMM 05-23-10-200-003. FOUND A CRACKED APU TURBINE BEARING RETURN LINE AND EVIDENCE OF FIRE IN THE APU ASSY. (APU IS A (RIVETED) TURBINE WHEEL). NO DAMAGE NOTED TO AIRCRAFT STRUCTURE. PLACARDED APU IAW MEL 49-10-01A. PLACARDED APU FIRE DET. EXT. SYSTEM IAW MEL 26-22-00A. PERFORMED RII INSPECTION AND AIRCRAFT WAS RETURNED TO SERVICE. AIRCRAFT IS SCHEDULED FOR APU REPLACEMENT ON 8/31/06.