As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU PNEUMATICS FAIL ON PUSH BACK. PERFORMED APU BITE. ALL LEG NORMAL SHUTDOWN, OPS CHECK GOOD IAW FIM 49-11-00-1. ENG STARTED AND PACK MODE OPS CHECK GOOD. REMOVED AND REPLACED APU SURGE VALVE FILTER IAW AMM 49-53-06, OPS CHECKED GOOD.