As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EPSU BATTERY EMER L FAULT ON AAP WHEN EMERGENCY LIGHT OPS CHECK IS COMPLETED. REPLACED LEFT EMER PWR SUPPLY AND BATTERY PER AMM 33-51-38. TEST OK. ROTABLE PARTS CHANGE WAS INDICATED - TT # 1248304 SN OFF 8072 IPC REFERENCE # POWER SUPPLY, C OFF 31-3350-9-9001 8072 ON 31-3350-9-9001 8098.