What was found
AIRCRAFT 3016, EMERGENCY LIGHTS OUT AT SEATS 3B, 4B, 10C, 17C, 18C, 21C, AND 22C. CORRECTIVE ACTION: REPLACED EPSU 15WL AND BATTERY PACK. REFERENCE A-321 AMM 33-51-38-400-001-A AND 33-51-38-400-002-A. OPS CHECK OK. (LP 8428436 - AIRCRAFT WAS GROUNDED)