What was found
FOR FLIGHT 3853 DURING GROUND CHECKS MAINTENANCE FOUND THE FORWARD EMERGENCY LIGHTS WERE INOPERABLE AND THE AFT PORTION WERE DIM AND THEN WENT DEAD. THE FLIGHT WAS CANCELED AND THE AIRCRAFT WAS REMOVED FROM SERVICE. REMOVED AND REPLACED ALL FOUR BATTERY PACKS IAW AMM 33-51-17. PART NUMBER ON AND OFF IS 2013-1A. NR 1 SERIAL NUMBER OFF 104935, NR 2 SERIAL NUMBER OFF IS 104548; NR 3 SERIAL NUMBER OFF 79159 AND NR 4 SERIAL NUMBER OFF IS 70394. THE OPERATIONAL CHECKS WERE GOOD AND THE AIRCRAFT WAS RETURNED TO SERVICE.