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"Peter Duniho" wrote in message
... "Paul Sengupta" wrote in message ... Turbines do suffer from manufacturing defects (if I recall, there was an uncontained failure in the 90's on some rear-engine jet -- 727, DC-9 or something like that -- where the blade failure was due to some metallurgical problem). Sioux City DC10. Not actually the accident I'm thinking of. But yes, that's another example of blade failure (did they eventually determine it was a manufacturing defect, or a maintenance problem?). They say it was a manufacturing defect about the size of a grain of sand. http://www.ntsb.gov/speeches/former/hall/jh970912.htm "Metallurgical examination of the titanium fan hub revealed that a fatigue crack originated from an inclusion near the surface of the hub's bore. The inclusion had been formed during the titanium vacuum-melting process at the time of manufacture about 2 decades earlier, which developed an internal cavity during final machining and/or shot peening. At the time of manufacture, the fan hub had been ultrasonic and macroetch inspected." The accident to which I was referring only involved one or two fatalities, of a passenger or of passengers sitting right next to the engine. Yes, I know the one you're talking about. It's mentioned on the page referenced above: "We will soon conclude our investigation on that Delta Air Lines MD-88 engine failure I mentioned earlier. Metallurgical examination of the fracture surface of that fan hub revealed that a fatigue crack had originated from a machining defect in a tie rod hole. Further, the fan hub had been fluorescent particle inspected only seven months before the failure, when the crack was estimated to be approximately ½-inch long." Also http://www.ntsb.gov/pressrel/1998/980113d.htm Paul |
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