As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING MAINTENANCE INSPECTION FOUND THE EMERGENCY BATTERY NR 4 REQUIRES REPLACEMENT. THE AIRCRAFT WAS REMOVED FROM SERVICE. REMOVED AND REPLACED THE EMERGENCY BATTERY NR 4 AND CHARGER IAW AEA MTX WC 33-700-19 AND 33-700-17. THE OPERATIONAL CHECK WAS GOOD. THE AIRCRAFT WAS RETURNED TO SERVICE.