As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU AUTOMATICALLY SHUTDOWN IN FLIGHT DUE TO AN OVERHEAT. SMOKE FROM OVER-HEATED APU ENTERED CABIN. UPON VISUAL INSPECTION OF APU FOUND APU OIL TO BE LOW. ADDED OIL AS REQUIRED IAW 650XLS AMM 12-10-00. RAN APU LOADED WITH ACM FOR APPROX. 20 MIN EGT PEAKED AT 522 DEG AND STABILIZED AT 502 DEG. ALL PARAMETERS IN LIMITS IAW 560XLS AMM 49-10-00.