What was found
THE FORWARD AND AFT AUXILIARY FUEL TANKS WERE REMOVED AND RE-INSTALLED FOR FUSELAGE LOWER LOBE INSPECTION AND FUEL TANK INSPECTION. AFTER RE-INSTALLATION, THE AUXILIARY TANKS WERE BEING FUELED FOR OPS AND LEAK CHECK. DURING FUELING, THE FORWARD NR 4 AUXILIARY FUEL TANK RUPTURED. THE CAUSE IS STILL BEING INVESTIGATED BY THE REPAIR STATION AND THE AUXILIARY FUEL TANK MANUFACTURER.