Re: Swissair MD-11 (SR 111, JFK-GVA) crash off Nova Scotia

Date:         05 Oct 98 00:27:07 
From:         jmaddaus@NO-SPAM.usa.net (John S. Maddaus)
Organization: MindSpring Enterprises
References:   1 2 3 4
Followups:    1
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"Richard Rea" <rrea@xmission.com> wrote:
>Karl Swartz wrote in message ...
>>>why wouldn't it be possible to open the side cockpit windows?
>>
>>I think there was mention of that being done in the case of ValuJet 592.
>
>There are a couple of problems with opening windows if indeed there is an
>on-board fire.  One is that you are adding lots of fresh air to feed the
>fire.  If it is a smoldering fire, then the appropriate measure would be to
>don oxygen masks and avoid allowing outside air into the cabin.  Also, if
>you have smoke entering the cabin and you open windows or fresh-air vents,
>the pressure inside the cabin will drop relative to the outside air (flow
>around a large body will tend to cause a decrease in pressure within the
>body) and will exasperate the problem, i.e. cause *more* smoke to enter the
>cockpit.  I don't think that it would have been too good an idea for the
>pilot to try to stick his head out of the window, as there wouldn't have
>been much to see that would be helpful (it was dark, wasn't it?).  You also
>wouldn't be able to see the instruments.

Also, I remember reading an article dealing with the amount of outside
air vs. recirculated air that is available throughout the ac.  I don't
know whether this is true for all aircraft types, but the
generalization was that the cockpit is approximately 90% ventilated
from the outside, while first class is 50% and coach is down to 20%.
My question then is can a pilot control the amount of new air vs.
recirculated air in the cabin/cockpit, does it really vary (and this
may simply be because of placement of intakes, vents, etc. and can a
pilot completely shut off outside air entering the cabin in case of a
fire?

jmaddaus@usa.net