Date: 04 Jan 97 03:55:48 From: "David K. Cornutt" <email@example.com> Organization: Residential Engineering References: 1 2 Followups: 1
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This has been a very interesting discussion, but I'm wondering if it isn't focusing on the wrong things. If I recall correctly an article that I read in AW about two years ago, there is *no* case on record of a scheduled airliner (jet-equipped) ever suffering two independent engine failures on one flight. Therefore, it seems to me that crashes stemming from engine failures can be divided into two categories: multiple failures with a common cause, and a single uncontained failure that makes the plane unflyable. Examples: Of the first category, two come to mind. In 1985 (I think) there was an Eastern L1011 that took off from Miami with all three engines leaking oil (a ramp technician who removed oil plugs from the engines, in order to check the oil levels, failed to notice that the replacement plugs that he installed lacked O-rings to seal them). And in 1976, there was a Southern Airlines 727 that flew through a thunderstorm and had all three engines extinguished by water ingestion. In the second category, there's the DC-10 in Iowa that lost all of its hydraulics after an uncontained engine failure, and the recent El Al 747 could be added to this list. Clearly, in neither of these cases does having more engines turning make any positive difference. (In fact, in the second case, it might be argued that twins have a very slight advantage over three- and four-engined aircraft.) It appears to me that much more progress could be made by trying to improve redundancy among systems that support engine operation, and improving containment of engine failures. Trying to further mitigate the already-improbable case of multiple independent engine failures doesn't look like a winning strategy. Comments? --- David K. Cornutt, Residentially Engineered, Huntsville, AL email: firstname.lastname@example.org I'm a rocket scientist. I know the difference between an increase and a decrease.