What was found
DURING THE ROUTINE TROUBLESHOOTING OF A FUEL LEAK IN THE PYLON AREA, TECHNICIANS DISCOVERED MULTIPLE PYLON ATTACH FITTING FASTENERS SHEAR ON THE NR 1 AND NR 4 PYLON. REFERENCE FASTENERS ARE COVERED UNDER AD 2005-14-08 AND ASSOCIATED SERVICE BULLETINS. THE SUBJECT AIRCRAFT HAD PREVIOUSLY HAD SUBJECT AD TERMINATED PER STEP (M) OF AFOREMENTIONED AD AND REFERENCE FASTENERS REPLACED WITH TITANIUM FASTENERS PER SB 747-57A2312. Q2SA HAS ACCOMPLISHED RESEARCH OF HISTORY OF AIRCRAFT FOR EVIDENCE OF HARD LANDING, OR OTHER CONTRIBUTING FACTORS. ROOT CAUSE HAS NOT BEEN DETERMINED AT THIS TIME. SUBJECT AIRCRAFT IS BEING REPAIRED PER SB 57A2312 AND ADDITIONAL SUPPLEMENTAL INSPECTION TO BE ACCOMPLISHED PER BOEING INSTRUCTIONS.