As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) APU SURGING. UNIT REMOVED AND INSPECTED. UPON DISMANTLING THE COMBUSTION SECTION, THE NUT HOLDING THE TURBINE BEARING HOUSING TO THE MAIN BODY WAS MISSING. WHEN THE NUT CAME LOOSE IT WAS EJECTED THROUGH THE TURBINE NOZZLE AND WHEEL ASSY CAUSING UNREPAIRABLE DAMAGE. APU REPLACED.