How faulty wiring caused the crash of Swissair Fight 111.

On September 2, 1998, exactly 24 years ago today a seven-year-old Swissair McDonnell Douglas MD-11 with the registration number HB-IWF crashed in the Atlantic Ocean off the coast of Halifax, Nova Scotia killing all 229 passengers and crew. To this day, it remains the deadliest accident involving a McDonnell Douglas MD-11.

The pilot in charge of the aircraft was 50-year-old Urs Zimmermann, a former Swiss Air Force fighter pilot. At the time of the crash, Zimmermann had 10,800 flight hours, 900 of which were in the MD-11. The first officer for the flight was 36-year-old Stefan Löw, who had 4,800 flight hours, of which 230 were on the MD-11.

The flight was a regularly scheduled service between New York City and Geneva, Switzerland. The flight took off from John F. Kennedy International Airport (JFK) bound for Geneva Airport (GVE) at 20:18 local time. During the first 13 minutes of the flight the aircraft experienced a radio blackout which was later found to be a tuning error.

At 22:10, some 52 minutes after taking off, the flight deck detected the odor of smoke, which appeared to be coming from the aircraft's air-conditioning system. Four minutes later, the smell returned, and smoke became visible, prompting the pilots to make a pan-pan emergency call to Moncton Air Traffic Control (ATC). The pan-pan emergency indicated a problem, but it was not a full-scale emergency that would have resulted in a mayday call.

The captain requested a diversion to Boston Logan International Airport (BOS) in Massachusetts, 269 miles away. Instead of Boston Moncton, ATC told the plane to divert to Halifax Stanfield International Airport (YHZ) as it was only 66 miles away.

At 22:18 Moncton ATC handed over control of the flight to Halifax Airport Air Traffic Control as they were in charge of traffic in and out of Halifax International Airport. With the plane now just 30 miles out from Halifax, the crew requested more flight distance to allow the aircraft to descend safely from its current altitude of 21,000 feet. The pilots then asked for permission to dump fuel to reduce the aircraft's weight for landing. Halifax ATC directed to plane to fly south over St. Margarets Bay, where it would be safe to dump the fuel. Per Swissair procedures for unknown smoke in the cabin, the crew shut off the power to the cabin, which resulted in the fire spreading and shutting off the plane's autopilot.

At 22:24, the pilots informed Halifax ATC that they were flying the plane manually. Ten seconds later, they declared a Mayday emergency which turned out to be the last communication from the aircraft. At 22:31, the plane crashed into the Atlantic Ocean at an estimated 345 miles per hour, causing the plane to disintegrate instantly.

First on the scene were privately owned fishing boats operating from Peggy's Cove and Bayswater, who were soon joined by a Canadian Coast Guard ship and a Sea King helicopter from Canadian Forces Base (CFB) Shearwater in Nova Scotia. It was quickly apparent to all that of the 215 passengers and 14 crew that there were no survivors. With the help of DNA, Royal Canadian Mounted Police (RCMP) medical examiners positively identified all the victims.

The Transportation Safety Board of Canada (TSB) worked with the following agencies and companies while investigating the crash of Swissair Flight 111:

The Transportation Safety Board of Canada (TSB) concluded that the fire started in the upper right side of the cockpit. The fire quickly spread and degraded aircraft systems and the cockpit environment, ultimately losing control of the aircraft. The TSB of Canada concluded that the probable cause of the fire was a short circuit wire arcing event that ignited thermal and acoustic insulation cover materials. The aircraft did not have a fire detection and suppression system to alert the crew to a problem. Instead, the crew had to rely on smell to realize all was not well.

The crash of Swissair Flight 111 led to widespread changes in Federal Aviation Administration standards, mainly impacting aircraft wiring.

Journalist - Mark is an experienced travel journalist having published work in the industry for more than seven years. His enthusiasm for aviation news and wealth of experience lends itself to some excellent insight, with his work cited in Forbes amongst other publications. Based in Alicante, Spain.