TSB Report on Swiss Air 111
If the aircraft had followed the theoretical emergency descent profile, the first systems failure event apparent to the pilots-the disconnect of the autopilot at 0124:09-would have occurred on the landing approach in the vicinity of the Golf beacon, approximately 5 nm from the threshold of Runway 06. The aircraft would have subsequently experienced progressive systems failures on the approach. When the flight recorders stopped at 0125:41, the aircraft would have been at approximately 700 feet above the runway threshold elevation. The earliest estimated threshold crossing time was 0126:17, which would have been 1 minute, 35 seconds, after the pilots had declared an emergency. Approximately 35 more seconds would be required to land and stop the aircraft; therefore, the completion of the landing would have been at approximately 0127.
1.1 History of the flight
At approximately 0130, observers in the area of St. Margaret's Bay, Nova Scotia, saw a large aircraft fly overhead at low altitude and heard the sound of its engines. At about 0131, several observers heard a sound described as a loud clap. Seismographic recorders in Halifax, Nova Scotia, and in Moncton, New Brunswick, recorded a seismic event at 0131:18, which coincides with the time the aircraft struck the water.