As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: DURING CIDS OPERATIONAL CHECK OF THE EMERGENCY LIGHTING SYSTEM MAINTENANCE FOUND FAULT CODE 33 51 00 CLASS 1. REPLACED EMERGENCY POWER SUPPLY UNIT 10WL (AALA202206168977) AND THE EMERGENCY POWER SUPPLY UNIT BATTERY (AALA202206166743) PER AMM 33-51-38. A SATISFACTORY OPERATIONAL CHECK WAS ACCOMPLISHED.