As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU FIRE ON GROUND AFTER APPARENTLY NORMAL STARTUP - NO FIRE INDICATION OBSERVED ON FIRE DETECTION SYSTEM. FIRE WAS OBSERVED EXTERNALLY. FIRE EXTINGUISHER WAS DISCHARGED FOLLOWING QRH PROCEDURE.INSPECTED APU AND SURROUNDING AREA. FOUND TURBINE FAILURE. NO OTHER DAMAGE NOTED. INSPECTED RUDDER AND SKIN SURFACES. NO DAMAGE NOTED. MEL APU PER 49-00-1. PULLED APU CONTROL CB & SECURED.