As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER ARRIVING AND ENGINE SHUTDOWN WITH NO EXTERNAL ELECTRICAL POWER, THE COCKPIT AND PASSENGER COMPARTMENT DOOR OVERHEAD EMERGENCY LIGHTING FAILED TO ILLUMINATE. MAINTENANCE INSPECTED THE EMERGENCY LIGHTING SYSTEM AND FOUND TWO BATTERY PACKS DEFECTIVE, WHICH WERE REPLACED. MAINTENANCE ACCOMPLISHED A SUCCESSFUL OPERATIONAL TEST IN ACCORDANCE THE DOUGLAS MAINTENANCE MANUAL.