As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU MUFFLER AND EXHAUST PIPE REQUIRE REPLACEMENT DUE TO DAMAGE DURING APU FAILURE. *S/D* THE TURBINE WHEEL FAILED CAUSING UNCONTAINED SEPARATION. THE CAUSE IS BEING ADDRESSED BY INTRODUCTION OF CONTAINMENT AUGMENTATION RING THROUGH SERVICE BULLETIN 49-A7189 AND COA 0-9223.