From:         Steve Lacker <>
Organization: applied research laboratories
Date:         03 Nov 96 19:56:57 
References:   1 2 3 4 5
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C. Marin Faure wrote:

> The first jet engines were less reliable than the piston engines of the
> same era.

By "first jet engines" do you mean, for example, the J-57s of the 707? Or
do you literally mean the very earlyjets that were never used for passenger
service. If it is the former, I would like to hear more concrete evidence
that they were "less reliable" than a Wright 3350. You may well be right,
but it goes against EVERYthing I've read along those lines.

> They have steadily gotten more reliable until today engine
> failure can almost be ruled out as a potential problem, assuming proper
> maintenance and operational procedures, of course.

Again, "almost be ruled out" is a pretty strong term. I was shocked when
I first flipped through the NTSB report page
( to find a surprising number of
"uncontained engine failures." Most of these weren't losing whole fan
disks and killing people like the recent MD-88 or the Sioux City DC-10,
but most represent total engine failures nonetheless. Statistically, yes
its a small number of failures per number of flights... but in my book it
can't "almost be ruled out" until the total probability of such a failure
gets down to the "once in 10 years" sort of range. We aint there yet!

Stephen Lacker
Applied Research Laboratories, The University of Texas at Austin
PO Box 8029, Austin TX 78713-8029