As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: FAULT MESSAGE FOR EMERGENCY POWER SUPPLY UNIT 13WL DISPLAYED DURING SYSTEM TEST. REPLACED EMERGENCY POWER SUPPLY UNIT 13WL (AALA202603234119) AND BATTERY (AALA202603240294) PER AMM 33-51-38. A SATISFACTORY OPERATIONAL CHECK OF THE EMERGENCY LIGHTING SYSTEM WAS ACCOMPLISHED WITH NO FAULTS NOTED.