




The design and certification of the B 747 pylon was found to be inadequate to provide the required level of safety. Furthermore the system to ensure structural integrity by inspection failed. This ultimately caused – probably initiated by fatigue in the inboard midspar fuse-pin – the n°3 pylon and engine to separate from the wing in such a way that the n°4 pylon and engine were torn off, part of the leading edge of the wing was damaged and the use of several systems was lost or limited. This subsequently left the flight crew with very limited control of the airplane. Because of the marginal controllability a safe landing became highly improbable, if not virtually impossible.
