ANNEX I

 

MD-11

SERVICEABILITY

STATISTICS

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Boeing issued a press release on 3 September boldly stating: "This [SR 111] is the second hull-loss accident involving an MD-11 in the nearly eight years since the airplane type entered commercial service. The 178 MD-11’s that make up the world fleet have proven themselves in terms of safety, reliability and performance." However, this statement is false. Because aircraft crashes are an insufficient criteria of safety. Dr. Alex Richman, a Halifax epidemiologist and former professor at Dalhousie University who turned his expertise to airline safety after his son was killed in a 1991 Los Angeles runway collision, formed a team that assessed critical problems in 43 MD-11’s that filed service difficulty reports (SDR’s) in the United States between 1991 and 1995. During this period there were 167 safety-related reports and recommendations filed on fewer than 50 United States based MD-11’s. Almost a quarter of the MD-11’s [23.3 per cent] took the precautionary procedure of dumping fuel at least once [compared with B757: none].

More than 37 per cent of the MD-11’s shut down engines [B757: 20 per cent]. More than 72 per cent of MD-11’s made unscheduled landings [B757: 51.3 per cent]. The B757 is the only aircraft to be compared with, because there are no other wide-bodied, tri-engined jets to compare with the MD-11. Also, the two aircraft are of similar vintage. Richman found the number of safety reports on MD-11’s particularly disturbing given the departures involved: 96,500 for the MD-11’s compared with almost 2,2 million for the B757’s, or almost 23 times as many B757 takeoffs. Richman also cited flying hours: 594,400 for MD-11 compared with 5.2 million for the B757. Results are troublesome: Vibration was reported in 27.9 per cent of MD-11’s and 7.7 per cent of B757 ‘s. Warning lights came on at least once in 74.4 per cent of MD-11’s and only half of B757’s. There were hydraulic malfunctions in 39.5 per cent of MD-11’s and only 14 per cent of B757’s. Air Safety Week magazine [2nd November issue] mentions an increase in reported smoke or fire related incidents since the crash. More than 30 such incidents should have been reported to Canadian authorities. The technical newsletter also states that in-flight fires, smokes or fumes are the third most significant cause of unscheduled landings. The findings, based on a comprehensive review of 350,000 Service Difficulty Reports in the database of the FAA, suggests that SR 111’s decision to divert to Halifax was by no means a rarity. Between 26 March 1990 and 11 September 1998 there were no less than 1,089 unscheduled, precautionary landings made involving fire, smoke or suspicious odors [source: Aviation DataSource, Denver]. This is an average of 120 per annum, or nearly 2.5 a week. The newsletter stated that about 60 per cent involved smoke in the cockpit or cabin. The fire and smoke related incidents trailed illumination of cockpit warning lights [6,074 unscheduled landings] and fluid loss [1,309]. The Aviation DataSource study focused on big jets operated in the United States The Halifax periodical Aviation Quantitative Reports on Safety reports the number of passengers affected by in-flight fires increased 167 per cent between 1986-1990 and 1991-1995, to 2,656 from 1994. According to Armin Bruning, a United States electrical engineer, electrical wiring in aging aircraft is a link between many of these incidents. Much of the wiring aboard commercial jets is covered with biodegradable insulation a few human hairs thick. Bruning is head of Lectromechanical Design Co., a Virgina based research and design firm.

The FAA announced in October 1998 it plans to conduct service reviews of non-structural components - including wiring - in 1,837 older planes. The Swissair jet was delivered in 1991 and would not have been subject to this order.

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