While attempting to return to Schiphol Airport, the crew lost control of the aircraft, which crashed into an apartment building in a suburb of Amsterdam. The three crew members and one non-revenue passenger were killed. In addition, 43 persons on the ground were killed, 11 persons were seriously injured and 15 persons received minor injuries in the Oct. 4, 1992, accident. The final report of the Netherlands Aviation Safety Board (NASB) concluded that the probable causes of the accident were: "The design and certification of the B-747 pylon was found to be inadequate to provide the required level of safety. Furthermore, the system [designed] to ensure structural integrity by inspection failed. This ultimately caused - probably initiated by fatigue in the inboard midspar fuse pin - the No. 3 pylon and engine to separate from the wing in such a way that the No. 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.