As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT IN BASE MAINTENANCE: EMERGENCY POWER SUPPLY UNIT 14WL FAILS OPERATIONAL CHECK. MAINTENANCE REPLACED EMERGENCY POWER SUPPLY UNIT 14WL (AALA202211305883) AND BATTERY (AALA202211303921) IAW AMM 33-51-38. A SATISFACTORY OPERATIONAL CHECK WAS ACCOMPLISHED.