Re: Wing vs. tail-mounted engines?

Date:         19 Apr 2001 16:40:21 
From:         robinjohnson@bigfoot.com (Robin Johnson)
Organization: North Antarctica
References:   1 2 3 4
Followups:    1
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On 09 Apr 2001 15:37:00 , "Doug Holik" <drholik@prodigy.net> told us:

>"RF-X" <no@spam.com> wrote in message
>news:airliners.2001.117@ditka.Chicago.COM...
>> In article <airliners.2001.95@ditka.Chicago.COM>,
>> robinjohnson@bigfoot.com wrote:
>>
>> > 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?
>> > I would feel safer in a rear-engined model.
>>
>> I was under the impression that jets with underslung engines had a
>> method of jettisoning said engines in a ditch scenario, and this wasn't
>
>Not sure where you heard that but there is no way to jettison the engines.
>Some commercial aircraft, notably the MD-11 feature a "ditching" switch.
>All this switch does is close up the holes on the skin of the aircraft, APU
>Ports, Outflow Valve, etc...
>A means to jettison the engines does not sound like a good idea anyway, what
>if someone accidentally pressed the wrong button?

I didn't get much response to the above question in another ng (about
successful ditchings).  But I do remember that some of the early jets
with underslung engines, specifically the DC-8, had a pylon
arrangement that disconnected easily in the event of increased
resistance.  The example I saw was a DC-8-50 that overran into a soft
ploughed field on attempted takeoff at Heathrow sometime in the
mid-60s.  One engine (or more) had completely severed connection.  I
was told at the time it was arranged so to avoid smashing into the
wing fuel tanks: it presumably did not happen to the ET 767.  Which
aircraft had/have that as a feature, and why was it dropped?

--Robin Johnson
>
>Doug Holik