As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(AUS) APU FAILED DURING GROUND RUN - INVESTIGATION FOUND LARGE PIECES OF METAL IN THE MUFFLER AND THE LOWER SHROUD - SUBSTANTIAL EXTERNAL DAMAGE WAS ALSO PRESENT - FURTHER INSPECTION FOUND THAT THE APU HAD MOVED IN ITS MOUNTS - SUSPECT FAILURE DUE TO SEPARATION OF THE TURBINE WHEEL