As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: AFTER REPLACING WELS BATTERY WBU16, EMERGENCY LIGHTING TEST FAILED WITH MM 33-11416- CLASS 16 BATTERY POWER FAILED. MAINTENANCE REMOVED AND REPLACED WELS BATTERY WBU16 IAW AMM 33-51-07. EMERGENCY LIGHTING TEST PASSED AND MAINTENANCE MESSAGE 33-11416 CLEARED.