Swissair Flight 111

Swissair Flight 111 was a scheduled international passenger flight from John F. Kennedy International Airport in New York City, United States, to Cointrin Airport in Geneva, Switzerland. The flight was also a codeshare flight with Delta Air Lines. On 2 September 1998, the McDonnell Douglas MD-11 operating this flight crashed into the Atlantic Ocean southwest of Halifax Stanfield International Airport at the entrance to St. Margarets Bay, Nova Scotia, Canada, killing all 215 passengers and 14 crew members on board. The crash site was 8 km from shore, roughly equidistant from the small fishing and tourist communities of Peggys Cove and Bayswater. It is the deadliest accident in Swissair history, the deadliest involving the MD-11, and the second-deadliest aviation accident in Canada, behind Arrow Air Flight 1285R.

The search and rescue response, crash recovery operation, and investigation by the Government of Canada took more than four years and cost CA$57 million. The investigation carried out by the Transportation Safety Board of Canada (TSB) concluded that flammable material used in the aircraft's structure allowed a fire to spread beyond the control of the flight crew, resulting in the crash of the aircraft. Several wide-ranging recommendations were made, which were incorporated into newer US Federal Aviation Administration (FAA) standards.

Flight

At 22:10 ADT (01:10 UTC, 52 minutes after takeoff), while flying over Yarmouth, Nova Scotia, the flight crew detected an odour in the cockpit and determined it to be smoke from the air conditioning system. Four minutes later, the odour returned and smoke became visible, prompting the pilots to make a "pan-pan" radio call to Moncton Centre, the area control center (ACC) station in charge of air traffic over Nova Scotia. The pan-pan call indicated that there was an urgency due to smoke in the cockpit but did not declare an emergency as denoted by a "mayday" call. The crew requested a diversion to Boston (234 nmi away) before accepting Moncton ATC's offer of radar vectors to the closer Halifax International Airport in Enfield, Nova Scotia, 66 nmi away.

At 22:18 ADT (01:18 UTC), Moncton Centre handed over the plane's traffic control to the Halifax Terminal Control Centre, which was responsible for controlling traffic in and out of Halifax International Airport. Upon being advised by Halifax ATC that they were 30 nmi from Halifax airport, the crew requested more flight distance to allow the aircraft to descend safely from its altitude of 21000 ft at the time. The crew then requested permission to dump fuel to reduce their weight for landing. Halifax thus vectored the plane south toward St. Margarets Bay, where it was safe for the aircraft to dump fuel while remaining within 40 nmi of the airport.

In accordance with the Swissair checklist "Smoke/fumes of unknown origin", the flight crew shut off power to the cabin using the "CABIN BUS" switch, which also turned off the recirculating fans in the cabin's ceiling. This allowed the fire to spread to the cockpit, eventually shutting off power to the aircraft's autopilot. At 22:24:28 ADT (01:24:28 UTC), the crew informed Halifax that "we now must fly manually", followed by an emergency declaration. Ten seconds later, the crew declared an emergency again, saying, "...and we are declaring [an] emergency now, Swissair one eleven," and this was the last transmission received from Flight 111.

The aircraft flight data recorder and cockpit voice recorder stopped operating at 22:25:41 ADT (01:25:41 UTC). The aircraft's transponder briefly resumed transmission of secondary radar returns from 22:25:50 to 22:26:04 ADT (01:25:50 to 01:26:04 UTC), at which time the aircraft's altitude was 9,700 ft. After this, the aircraft could be tracked only through primary radar, which does not provide altitude information.

Crash

Engine No. 2 (the middle engine in the MD-11's tail section) was shut down by First Officer Löw approximately one minute prior to the time of impact. The shutdown of Engine No. 2 would have had a minimal effect on aircraft controllability. In a smoke-filled cockpit and with almost no flight instruments and little to no view outside, Löw may have become spatially disoriented and, as a result, flew into the sea. Another possibility is that while attempting to see outside the cockpit windows, Löw inadvertently pushed the control column forward, thus resulting in a descent and eventual impact with the water.

At 22:31:18 ADT (01:31:18 UTC), Flight 111 struck the ocean at an estimated speed of 345 mph. The impact time also coincides with seismographic recorders at Halifax and Moncton, which detected a seismic event at the time. The collision with the water decelerated the aircraft with approximately 350 g, causing it to disintegrate instantly, killing everyone on board. The location of the crash was identified as approximately 44°24′33″N 63°58′25″W.