As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU NO START. AHM INDICATES FDE 49100200 WITH MSG 4910620. APU PERF TREND MONITORING (APTM) ALSO INDICATE E-STARTER FAILURE. REPAIRED OR REPLACED AS NEEDED E-STARTER. FOUND MSG ON MAT 49-10620 ACTIVE ON ARRIVAL. CARRIED OUT T-S. REPLACED APU CRANK RELAY, NO HELP. CONFIRMED ELECTRIC STARTER AT FAULT. ITEM NON STOCK LHR. APU USABLE. APU TO BE STARTED ON DEPARTURE VIA EXTERNAL AIR SOURCE. REPLACED ELECTRIC STARTER, STARTS OK.