Communiqués

TSB # A99-20

Hull, Quebec (15 December 1999) - The wreckage recovery, or field phase of the Transportation Safety Board of Canada's (TSB) investigation into the September 1998 Swissair Flight 111 accident has been completed. The latest recovery effort, using the suction dredge ship "queen of the netherlands" brought to the surface 8 500 cubic metres of material. This material was offloaded on September 30 at a facility especially prepared for the purpose at Sheet Harbour, Nova Scotia, where the debris was sifted and sorted.

The sorting of the dredged material yielded an estimated additional million pieces of aircraft structure, components, and cargo, weighing some 12 725 kg. The total weight of aircraft wreckage recovered is over 127 090 kg or about 98 per cent of the original structural weight of the aircraft. The TSB is aware that there are still a number of pieces on the ocean floor; however, all reasonable recovery efforts have now been made and no further recovery work is planned.

The TSB wishes to thank the many people from the local area, from the various municipal, provincial, and federal government departments and agencies, and from the numerous commercial companies, who, together, contributed in a variety of important ways to the safety and success of these challenging recovery operations.

Examination and identification of this latest wreckage have provided investigators with several thousand items that have been segregated for further evaluation and analysis. These new items are from many areas of the aircraft, and include aircraft systems components, the front section of the aircraft, wires, cockpit pieces, and heat-damaged pieces. They will be further examined to assist in the ongoing task of assessing what went wrong aboard the MD-11 and why, and in identifying any safety deficiencies.

Other investigation work continues:

• Work is continuing to develop a methodology to determine, if possible, how the arcing occurred on the 17 arced wires that have been found. The work is following scientific procedures that are necessarily rigid and very time-consuming.
• The airflow patterns and the heat-damage signatures in the forward ceiling area of the aircraft are being documented and reviewed.
• Identification, analysis, documentation, and matching of the recovered aircraft components, structure, and wires, continue.
• Analysis of electrically driven components is being conducted to determine the status of various electrical systems at the time of impact with the water.
• Various projects to reconstruct selected portions of the front nine metres of the aircraft are continuing.

The investigation into this accident is very complex and time-consuming. Work is progressing at a rate appropriate for an accident of this complexity. As the investigation continues over the coming months, more fact-finding and safety analysis will be undertaken. To date, this investigation has led to the identification of a number of safety deficiencies and to safety actions concerning wiring, flight recorders, thermal acoustical insulation blankets, and a review of operating procedures. As other safety deficiencies are validated, further safety action will be taken.

NOTE: This update is based on information assembled by the investigation staff and will be amended as other facts are gathered. The investigation is not complete and one should not attempt to infer findings as to the causes and contributing factors of this accident on the basis of this update.

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