As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: AUXILIARY POWER UNIT DISCHARGE LIGHT ON DURING CRUISE. OPERATIONS TEST OF AUXILIARY POWER UNIT FIRE AND OVERHEAT DETECTION SYSTEM, PER AMM 26-13-00-710-001-A. ACCOMPLISHED AUXILIARY POWER UNIT FIRE DETECTION UNIT TEST PER AMM 26-13-34-710-051-A. OPEN AUXILIARY POWER UNIT COMPARTMENT AND CHECK AUXILIARY POWER UNIT AND CHECKED AUXILIARY POWER UNIT FIRE DETECTION LOOPS, NO DEFECTS FOUND.