As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) INSPECTION OF THE AUXILIARY POWER UNIT FOUND 4TH STAGE COMPRESSOR DISC CRACKED AT THE ACUTE CORNER FORMED BY THE DOVE TAIL AND DISC FRONT FACE. THE SIZE OF THE CRACK WAS APPROXIMATELY 0.300 INCH. THE COMPRESSOR DISC WAS REMOVED AND SCRAPPED.