What was found
EMER LT NOT ARM YELLOW CAS: ON CLIMB EMER LT NOT ARM CAS MESSAGE ILLUMINATED. THE EMER LIGHTS WERE ON IN THE BACK AND AFTER A FEW MINUTES STARTED FLASHING.// SIGNOFF// POWRED UP . AND VERIFIED DISCREPANCY GAINED ACCESS NUMBER 1 EMER BATTTERY AND NUMBER 2 EMER BATTERY. COMPLIED WITH SL 505-33-0005, FOUND AFT BATTERY AT FAULT NOTIFIED MCC: OF FINDINGS (BC-1-19-2022) TOP CHARGED EMER. BATTERLES WITH THE EXTERNAL POWER. C/W OPS CHECKS OF EMERGENCY LIGHTS WITH SAME RESULTS AFT BATTERY WILL NEED TO BE REPLACED RECIEVED CUSTOMER SUPPLIED NEW EMERGENCY BATTERY. ACCESSED AFT BATTERY. REMOVED AND REPLACED BATTERY C/W OPS CHECK ALL CHECKS GOOD CLOASED ACCESS AS NEEDED REF EMB 505S AMM 33-52-01.