As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEVELED OFF AT CRUISE 20 MIN AFTER DEPARTURE, APU LEVELED OFF AT CRUISE 20 MIN AFTER DEPARTURE, APU OIL QTY SHOWED FULL. 30 MINUTES LATER OIL QTY SHOWED 50. REMOVED AND REPLACED GEARBOX PRESSURE REG VALVE IAW AMM 49-27-12-4. RAN APU 1 HR, APU OPS CHS NORMAL NO LEAKS NOTED. (K)