What was found
AIRCRAFT WAS GROUNDED: EMERGENCY LIGHTS AT SEAT ROWS 8, 11, 12, 14, 15, 16, 17, 20 AND 21 ARE INOPERATIVE. MAINTENANCE FOUND A FAULT MESSAGE FOR EMERGENCY POWER SUPPLY UNIT 11WL DURING A SYSTEM BITE TEST. MAINTENANCE REPLACED EMERGENCY POWER SUPPLY UNIT 11WL AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK.