Re: Wing vs. tail-mounted engines?

Date:         04 Apr 2001 16:41:18 
From:         FilipPC.DeVos@rug.ac.be (Filip De Vos)
Organization: University of Ghent, Belgium
References:   1 2
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Robin Johnson (robinjohnson@bigfoot.com) wrote:

: Engines these days are very reliable.  It is not unknown for an engine
: to remain in position for five years.
: On the other hand, more and more ETOPS flights are being undertaken -
: the majority of North Atlantic crossings for example. Despite this,
: there have been very few ditchings.

I am aware of exactly no ditchings caused by ETOPS. In fact, I am aware of
no mid-ocean ditchings in the jet age. All jets lost at sea came apart in
mid-air (TW800, AI182, KL007) or shattered on impact (SR111)

: Just this month a United 767 on the climb-out from Lihue and bound for
: California, had a loss of power on both engines.  No harm done,

Engines require a continuous flow of fuel :)

: but.....
: I'm a little concerned about the dynamics of a ditching with
: underslung engines, though.  The Ethiopian 767 off the Comores,
: although a hijack situation with armed men on the flightdeck, looked
: good on the video until the last minute, when it seemed that the
: engines dug in asymmetrically, causing the fuselage to break up.
: Does anyone know of a successful ditching by a jet?

A SAS DC-8 at San Fransisco or LA (pilots were preoccupied with a faulty
landing gear light)

A JAL DC-8 Super sixty pulled reverse thrust on approach to Haneda, pilot
heard voices in his head. Not really a ditching. 24 killed.

More recently, a 707 cargo in Lake Victoria. Engines and landing gear was
sheared off, but the aircraft kept on floating, crew safe.

: I would feel safer in a rear-engined model.

In a ditching, I do not know. The engines do not hang down, and therefore
cannot 'dig in', but aircraft with tail-mounted engines tend to have wings
that are straight instead of pointing slightly upward, so instead of
digging in an engine, they can dig in the wingtip, with potentially the
same results.

--
"Who needs credibility around  |    Filip De Vos
 here?" -- T. L. Elifritz      |    FilipPC.DeVos@rug.ac.be