Communiqués

TSB # A07/99

(Halifax, Nova Scotia, 08 April 1999) - The Transportation Safety Board of Canada (TSB) will resume wreckage recovery sea operations by mid-month as it continues the investigation into last September's crash of Swissair Flight 111 (SWR 111).

To date, about 88 per cent of the MD-11 structure, by weight, has been recovered. About 33,000 pounds of aircraft debris have yet to be recovered. The research vessel CFAV "ENDEAVOUR" has been retained by the TSB from the Department of National Defence for the continuing recovery operation. The vessel is now undergoing preparations and will be equipped with two remotely operated vehicles (ROV) that will be able to identify and recover underwater wreckage. The ROVs will work in all areas of the crash site, and will be particularly useful for recovery operations in the difficult and challenging rocky areas of the debris field.

The Canadian Coast Guard vessel "PARIZEAU" was used last January and February to maintain the exclusion zone, and to survey and plot the wreckage field using an ROV, a Camerapod, and Videograb equipment that had good survey capability and limited recovery capability. With significant assistance from specialists from the Bedford Institute of Oceanography, much of the wreckage field was plotted; some pieces of wreckage were recovered by the "PARIZEAU" and brought to Canadian Forces Base Shearwater, Nova Scotia, for examination by TSB investigators.

As of 11 March 1999, the exclusion zone over the debris field was reduced by about 20 per cent to a four-square-mile area. The zone has recently been patrolled by Canadian Coast Guard vessels and members of the Royal Canadian Mounted Police (RCMP) using Fast Rescue Craft.

TSB investigators continue to try to determine whether there is any significance to a gap in radio communications between the accident aircraft and the Federal Aviation Administration air traffic controllers based in Boston Center. Approximately one hour before SWR 111 crashed into the ocean, the aircraft was given a radio frequency change to another Boston Center frequency. Up until that time, communications between the aircraft and other controllers in the Boston Center had been normal. After the frequency change was given, Boston Center made repeated attempts to contact SWR 111, but did not re-establish contact for a 13-minute period. The aircraft was under radar surveillance at all times during this gap in radio communications.

There is no communication recorded on the Boston Center ATC tape where flight crew or controllers discussed any gap in normal communications. Eleven minutes after radio contact was re-established with Swissair Flight 111, Boston Center handed over control of the aircraft to Canadian enroute controllers in Moncton Area Control Centre, New Brunswick, in accordance with normal procedures.

The Cockpit Voice Recorder (CVR) installed on SWR 111 employed a continuous-loop magnetic tape of 30 minutes' duration, so any cockpit conversations, flight deck noises or attempted crew transmissions occurring during the 13-minute period were subsequently overwritten on the aircraft's CVR, and therefore were not available to TSB investigators. Earlier this year, the Board recommended that by 01 January 2005, all CVRs have a recording capacity of at least two hours to enhance the capture of information needed for investigation purposes.

Investigative work in Hangar A at Shearwater is progressing. During the last month, most of the recovered aircraft parts were re-sorted in an attempt to find additional items of immediate interest. More than 500 boxes, of nearly 1 m³ each, of aircraft parts were re-examined. The process yielded over 1,000 additional exhibits that have now been identified as items of further interest; many of these items belong to the front part of the aircraft that is now being reconstructed.

Work is continuing on the identification, examination, heat-damage analysis, and documentation and matching of aircraft nose section pieces. The examination, identification, heat-damage analysis and matching of wire from the aircraft is also still under way. Aircraft maintenance records continue to be reviewed to seek trends or patterns that might assist in the ongoing investigation. Various electrically driven systems, such as the fuel pumps, continue to be examined to understand more fully which electrical systems were or were not functioning at the time of impact.