Aviation Investigation Report A98H0003

1.1  History of the Flight

This section summarizes, in chronological order according to Coordinated Universal Time (UTC),[1] the main events that occurred during the flight and that are directly related to the SR 111 occurrence ending with the aircraft's impact with the water near Peggy's Cove, Nova Scotia, Canada. Refer to Appendix A – Flight Profile: Selected Events for a graphical representation of the flight path of the aircraft.

At 0018 UTC (2018 eastern daylight savings time) on 2 September 1998, the McDonnell Douglas[2] (MD) MD-11, operating as SR 111, departed John F. Kennedy (JFK) International Airport in Jamaica, New York, United States of America (USA), on a flight to Geneva, Switzerland. Two pilots, 12 flight attendants, and 215 passengers were on board. The first officer was the pilot flying. At 0058, SR 111 contacted Moncton Air Traffic Services (ATS) Area Control Centre (ACC) and reported that they were at flight level (FL) 330.[3]

At 0110:38, the pilots detected an unusual odour in the cockpit and began to investigate. They determined that some smoke was present in the cockpit, but not in the passenger cabin. They assessed that the odour and smoke were related to the air conditioning system. At 0114:15, SR 111 made a Pan Pan[4] radio transmission to Moncton ACC. The aircraft was about 66 nautical miles (nm) southwest of Halifax International Airport, Nova Scotia. The pilots reported that there was smoke in the cockpit and requested an immediate return to a convenient place. The pilots named Boston, Massachusetts, which was about 300 nm behind them. The Moncton ACC controller immediately cleared SR 111 to turn right toward Boston and to descend to FL310. At 0115:06, the controller asked SR 111 whether they preferred to go to Halifax, Nova Scotia. The pilots expressed a preference for Halifax, which was considerably closer. They immediately received an ATS clearance to fly directly to Halifax, which was by then about 56 nm to the northeast. At this time, the pilots donned their oxygen masks.

At 0116:34, the controller cleared SR 111 to descend to 10 000 feet above sea level,[5] and asked for the number of passengers and amount of fuel on board. The pilots asked the controller to stand by for that information. At 0118:17, the controller instructed SR 111 to contact Moncton ACC on radio frequency (RF) 119.2 megahertz (MHz). SR 111 immediately made contact with Moncton ACC on 119.2 MHz and stated that the aircraft was descending out of FL254 on a heading of 050 degrees[6] on course to Halifax. The controller cleared SR 111 to 3 000 feet. The pilots requested an intermediate altitude of 8 000 feet until the cabin was ready for landing.

At 0119:28, the controller instructed SR 111 to turn left to a heading of 030 for a landing on Runway 06 at the Halifax International Airport, and advised that the aircraft was 30 nm from the runway threshold. The aircraft was descending through approximately FL210 and the pilots indicated that they needed more than 30 nm. The controller instructed SR 111 to turn to a heading of 360 to provide more track distance for the aircraft to lose altitude. At 0120:48, the flight crew discussed internally the dumping of fuel based on the aircraft's gross weight, and on their perception of the cues regarding the aircraft condition, and agreed to dump fuel. At 0121:20, the controller made a second request for the number of persons and amount of fuel on board. SR 111 did not relay the number of persons on board, but indicated that the aircraft had 230 tonnes (t) of fuel on board (this was actually the current weight of the aircraft, not the amount of fuel) and specified the need to dump some fuel prior to landing.

At 0121:38, the controller asked the pilots whether they would be able to turn to the south to dump fuel, or whether they wished to stay closer to the airport. Upon receiving confirmation from the pilots that a turn to the south was acceptable, the controller instructed SR 111 to turn left to a heading of 200, and asked the pilots to advise when they were ready to dump fuel. The controller indicated that SR 111 had 10 nm to go before it would be off the coast, and that the aircraft was still within 25 nm of the Halifax airport. The pilots indicated that they were turning and that they were descending to 10 000 feet for the fuel dumping.

At 0122:33, the controller heard, but did not understand, a radio transmission from SR 111 that was spoken in Swiss–German, and asked SR 111 to repeat the transmission. The pilots indicated that the radio transmission was meant to be an internal communication only; the transmission had referred to the Air Conditioning Smoke checklist (see Appendix B – Swissair Air Conditioning Smoke Checklist).

At 0123:30, the controller instructed SR 111 to turn the aircraft farther left to a heading of 180, and informed the pilots that they would be off the coast in about 15 nm.[7] The pilots acknowledged the new heading and advised that the aircraft was level at 10 000 feet.

At 0123:53, the controller notified SR 111 that the aircraft would be remaining within about 35 to 40 nm of the airport in case they needed to get to the airport in a hurry. The pilots indicated that this was fine and asked to be notified when they could start dumping fuel. Twenty seconds later, the pilots notified the controller that they had to fly the aircraft manually and asked for a clearance to fly between 11 000 and 9 000 feet. The controller notified SR 111 that they were cleared to fly at any altitude between 5 000 and 12 000 feet.

At 0124:42, both pilots almost simultaneously declared an emergency on frequency 119.2 MHz; the controller acknowledged this transmission. At 0124:53, SR 111 indicated that they were starting to dump fuel and that they had to land immediately. The controller indicated that he would get back to them in just a couple of miles. SR 111 acknowledged this transmission.

At 0125:02, SR 111 again declared an emergency, which the controller acknowledged. At 0125:16, the controller cleared SR 111 to dump fuel; there was no response from the pilots. At 0125:40, the controller repeated the clearance. There was no further communication between SR 111 and the controller.

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. The aircraft was destroyed by impact forces. There were no survivors.

The accident occurred during the hours of darkness. The centre of the debris field, located on the ocean floor at a depth of about 55 metres (m) (180 feet), was at the approximate coordinates of latitude 44°24'33" North and longitude 063° 58'25" West.

Table 1 conveys the general time frame of the events between the first detection of an unusual odour in the cockpit and the time of impact with the water.

Table 1: Elapsed Time for Key Events

UTC Time Elapsed Time (minutes) Event
0110:38 00:00 Unusual smell detected in the cockpit
0113:14 02:36 Smoke assessed as visible at some location in the cockpit; no smell reported in cabin
0114:15 03:37 SR 111 radio call: "Pan Pan Pan"; diversion requested naming Boston (It is unknown whether visible smoke was still present in the cockpit)
0115:36 04:58 Decision made to divert to Halifax, Nova Scotia
0120:54 10:16 Decision made to dump fuel
0123:45 13:07 CABIN BUS switch selected to OFF
0124:09 13:31 Autopilot 2 disengages, and the flight data recorder (FDR) begins to record aircraft system failures
0124:42 14:04 Emergency declared
0125:02 14:24 ATS receives last communication from SR 111
0125:41 15:03 Recorders stop recording
0131:18 20:40 Impact with water

For a more detailed description of the timeline, sequence of events, and flight profile, refer to sections 1.18.8.3 and 1.18.8.4, and to Appendix A – Flight Profile: Selected Events and Appendix D – Timeline.


[1]    All times are Coordinated Universal Time (UTC) unless otherwise noted. In UTC time, the flight occurred on 3 September 1998. For eastern daylight savings time, subtract four hours; for Atlantic daylight time, subtract three hours.

[2]    On 1 August 1997, McDonnell Douglas (MD) merged with The Boeing Company, and Boeing became responsible for the MD-11 type certificate.

[3]    Altitudes above 18 000 feet are indicated as flight levels (FL) and are based on a standard altimeter setting of 29.92 inches of mercury. To derive an approximate altitude from a flight level, add two zeros to the indicated FL. For example, FL330 is about 33 000 feet above sea level.

[4]    Pan Pan is an expression, spoken three times in succession, used in the case of an urgency: a condition concerning the safety of an aircraft or other vehicle, or of some person on board or within sight, but that does not require immediate assistance (as defined by International Civil Aviation Organization AN10II, Chapter 5, paragraph 5.3.1.1).

[5]    All altitudes below 18 000 feet are indicated as above sea level, unless otherwise noted. Note: Sea level is equivalent to mean sea level.

[6]    All headings are degrees magnetic unless otherwise noted.

[7]    The controller had indicated earlier to the crew that they would have about 10 nautical miles (nm) to fly before crossing the coastline. When initially cleared to turn left, the aircraft had been flying at almost 7 nm per minute and had travelled slightly farther north than the controller had originally estimated, before starting the turn.


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Date de modification :
2012-07-27