As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CRP - DURING PREFLIGHT, AFTER TESTING EMERGENCY LIGHTS, THE FORWARD HALF WOULD NOT TURN OFF. MAINTENANCE REMOVED AND REPLACED THE POWER SUPPLY UNIT BATTERY PACK AT 43WL. OPERATIONAL CHECK WAS GOOD AND AIRCRAFT WAS RETURNED TO SERVICE. (M)