Communiqués

Investigation Update on the Swissair Flight 111 Accident

December 21, 1998

(Halifax, Nova Scotia, 21 December 1998) - The multi-faceted, complex, international investigation into the crash of Swissair Flight 111 continues.

Material is still being recovered from the seabed with the scallop dragger "ANNE S. PIERCE." The laser-line-scanning of the debris field shows that the field has been spread somewhat, although it is still within an area less than a mile square. So far, about 85 % of the aircraft by weight has been recovered, including about 60 % of the forward fuselage. It is estimated that there is still about 19,000 kilograms of aircraft wreckage that has not yet been recovered.

Some of the system components that have been recovered and are being analysed are as follows: all 8 flap actuators; 5 of 6 slat actuators and 30 of 38 slat tracks; all 10 spoiler actuators; 15 of 17 fuel boost pumps; both right and left fuel dump valves; portions of all 3 air conditioning packs; and 118 out of 148 passenger oxygen generators. Other investigation work also under way includes: the identification, examination and analysis of heat-damaged structural components and aircraft wiring; the continuing analysis of flight recorder and FADEC (Full Authority Digital Electronic Control) data; the examination and the analysis of fuel system components, fire extinguishers, engines, and other on-board systems.

The reconstruction of the forward section of the fuselage is continuing. There are more than 5,000 separate pieces that are believed to belong to the area being reconstructed. Many of these pieces are small and distorted by the impact forces; therefore, determining the specific location as to where they fit is a difficult and time-consuming process. The reconstruction of the forward area of the fuselage will give investigators a three-dimensional picture of the heat-damage pattern and will potentially help investigators localize the source of the initiating event.

The TSB investigation into the crash of Swissair Flight 111 has been under way, non-stop, seven days a week, for almost four months. With the Christmas season approaching, operations will be reduced from 23 December, 1998 to 3 January 1999 to allow investigators the opportunity to spend some time with their families.

Vic Gerden, the TSB investigator-in-charge of this accident, said, "although work is continuing to extract all possible information from the aircraft's recorders, the investigation is relying on traditional investigation methods that require the systematic examination of the more than one million pieces of wreckage recovered."

As information on safety deficiencies comes to light throughout this investigation, the information will be passed on to the regulators, the manufacturers, and to the operators. For example, TSB investigators have noted that in some other MD-11s, some wire insulation above the forward right and left passenger doors had been chafed. Although it is not known what relationship, if any, this wiring had with the cause of the accident, this information was provided to the FAA (Federal Aviation Administration of the United States). The FAA in turn issued an Airworthiness Directive (AD) to all operators of MD-11 aircraft requiring them to inspect the area, to report their findings to the FAA, and to correct any deficiencies encountered.

The TSB investigation into this accident is ongoing. Additional factual information will be provided as it becomes available.

Previous Investigation Updates and photographs may also be viewed at the TSB web site.

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