What was found
(AUS) WING OUTBOARD SKIN CRACKED IN THE AREA ADJACENT TO THE TIP TANK REAR SUPPORT BRACKET ONTO WING REAR SPAR. FURTHER INVESTIGATION FOUND THE TWO RIVETS ATTACHING THE WING END RIB TO THE REAR SPAR HAD SHEARED ALLOWING THE RIB AND SPAR TO FLEX INDEPENDENTLY PLACING SEVERE STRESS ON THE UPPER AND LOWER SKINS AND CORNER DOUBLERS. UPPER AND LOWER DOUBLERS WERE FOUND CRACKED AND A NUMBER OF RIVETS ALONG THE RIB UPPER AND LOWER FLANGES WERE LOOSE AND WORKING. SUSPECT CAUSED BY UPWARDS LOADS IMPOSED ON THE REAR TIP TANK ATTACHMENT DUE TO A LARGE VOLUME OF FUEL FORWARD OF THE MAIN ATTACHMENT POINT.