Re: A Dual Engine Failure ? -- Chances are Astronomical..!


"Jason P" <jaspetr@xxxxxxxxx> wrote in message news:13p2gfr5bkkv62c@xxxxxxxxxxxxxxxxxxxxx

"Chris S" <invalid@xxxxxxxxxxx> wrote in message news:fmrdhs$28ua$1@xxxxxxxxxxxxxxxxxxxx

"Jason P" <jaspetr@xxxxxxxxx> wrote in message news:13p2c6e3cfof1ef@xxxxxxxxxxxxxxxxxxxxx

"Chris S" <invalid@xxxxxxxxxxx> wrote in message news:fmr809$1vba$1@xxxxxxxxxxxxxxxxxxxx

"Jason P" <jaspetr@xxxxxxxxx> wrote in message news:13p26nrepp4gn5c@xxxxxxxxxxxxxxxxxxxxx

"FriarTuck" <none@xxxxxxxxxxx> wrote in message news:Lc7kj.62908$h35.27711@xxxxxxxxxxxxxxxxxxxxxxx
On Fri, 18 Jan 2008 10:51:46 -0800, Jason P wrote:

Maybe it was bad JP4 fuel or a flawed connecting electro-mechanical link
between the two engines.


software bug common to both systems perhaps, or switchover failed as well
as bug in one system... I have seen supposed fail safe switch over
systems actually fail to switch or be correctly in sync..... that was a
close shave....

I heard that the two systems run completely different code on air frame
dual redundancy.


Hmmmm... likely it's something small and obviously overlooked in the design phase.

As you say ...an unforseen code glitch, or a hardware interlink not doing the its thing during a critical stage of the glidepath. It's good the pilot opted to put her down as he did. Another pilot might have tried to power-out, to no avail, putting the aircraft in an attitude not conducive to getting everyone home alive.

The 777 uses fly by wire, if there is a loss of power to the control surfaces there is mechanical backup systems.

A RAT -- Ram Air Tubine extended mechanically, most-likely by bottled compressed air.

There is also another system which I can't recall at the moment.

As for the engines I doubt any good design would work the engines using the same unique system.

Normal aicraft redundancy design used throughout... of course it goes without saying I think, depending on who your are talking to.

That is why I questioned your original assumption.

It may be the same control method, ie hardware, but they wouldn't share it, each would be separate to prevent just this issue.

On some aircraft -- pre-fly-by-wire -- they had dual hydraulics, dual electrical, dual electronics, etc.

Even fly by wire have seperate avionic systems.


Initial though isn't code that hasn't been checked but maybe code that has been corrupted, possibly even sabotage can't be ruled out.


Good points...! Though dual codes, trying to override each other could do thing no one ever considered to electronic hardware -- crash..!

I doubt dual code, whatever you mean by that.

Issues of using different (dual) code was raise by another poster... following the thread, completely, would resolve this for you.

Apart from the poor English, what you seem to be saying is taht you are using another posters claims without understanding them yourself.

Computer error, well there should be redundancy and even then there will be a method for a master to take control of the slaves.
However if it is code problem then it may not be directly in the computer systems but in some specific control unit, the logic, a interface issue.



Egggzackly... my point!

Really, was that after you claimed "Maybe it was bad JP4 fuel"

The chip gets divergent instructions and says "I can't work for two bosses and quits." ...Slave system/sub-system goes kerfluey. ...Hydraulics, electrical, flight sensors, and so on, to infinity, could or might fail, singularly or in any combination together.

I think your looking at it from the wrong end.
It wouldn't be a computer error in the cockpit due to the slave master system, what probably has gone wrong if it is a corrupted code is somewhere down the line.
The instruction from the cockpit went out ok, but it's transmission or action at the component level of engine control was changed which gave engine issues.

.

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