Re: AA965 proves Airbus bashers deadly wrong

From: (Mike Cross)
Organization: Carleton University
Date:         22 Jan 96 04:40:40 
References:   1 2 3 4 5
Followups:    1
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Robert Ashcroft (rna@gsb-crown.Stanford.EDU) wrote:

> So you concede.  Thank you.  There was no need for Airbus to change the
> interface on its airliners.

I don't believe it is a matter of conceding.  The point was that there was
no overwhelming reason to switch to side stick controlers.  However after
studing the matter Airbus found side stick controlers to be superior.
Several of the reasons have been mentioned such as visibility of your EFIS
and the more natural feel a sidestick has for flying than a yolk.  The
fact that military aircraft use sticks is proof of the last point.  In
fact even MD's new military transport uses side sticks.

I find as I read these posts that many individuals choose the "well it's
always been done this way" defense of Boeing's continued use of yolks and
traditional cockpit structure.  However if something better comes along
there should be very little reason not to change.  It's unfortunate that
so many individuals choose to reject advancements.  You do realize that
when the automobile was produced many people said you would suffocate when
the car reached 30 MPH.  You seem to be the same kind of person that would
say such a thing.

> There's a massive difference.  Hydraulics and the like obey physical
> laws that are described by continuous mathematics.  While it has an
> infinite number of states, the behavior in all states can be accurately
> described by testing at a finite number of those states, by exploiting
> the continuous nature of the system.

> Compare to digital control:  While there are a finite number of states,
> the number of such states is so huge as to be infeasible to test all of
> them.  Moreover, testing at any number of them need not tell you _anything
> about the behavior in the untested states because of the non-continuous
> nature of the mathematics that describe the system.

> Why would you want to?  Note: ABS existed before the advent of
> computer control.  There were ABS on the Comet jetliner, first
> jet airliner in the world.

You have not responded to the comment about elevators.  Are you afraid to
ride the elevator?  You would probably be the type of person who was
against human operators being replaced with computer controls.

> However, it is not always the case that remaining within safe wing-strength
> limits is the desirable thing to do, if the alternative is death.

> See the difference?

No I don't see the difference.  You have chosen to state many facts that
are isolated in nature to a specific point you wish to support.   The fact
of the matter is there will be design flaws with any system no matter who
makes it.  I'm not talking glaring weakness but flaws which will be hidden
until a strange set of conditions and factors confront an aircraft.  Such
as your pushing the aircraft pasts its limits in order to save it
argument.  It's a nice argument to bash Airbus but it is misguided because
of the very rare nature of the incident you speak about.

I might choose to bash Boeing now because of the accidents that have or
might happen because they allow their pilots to push the aircraft beyond
it's design limits causing failure.  However I will not because it is a
limitation in design that is impossible to defend against if you choose
Boeings mindset.  (If you allow your pilots to have this type of
overrideing control because it is your belief that is right to do so you
must live with the consequences of actions those pilots might take
that cause an accident.  Just as Airbus will have to live with any
accidents caused because their computer system did not give the pilot
enough "room" to manouver.) It is also a limitation that will very rarely
come to light in an accident.  The point I am making is that it does not
matter which design you decided to go with there are always limitations.  The
fact that the systems we talk about are designed by humans means that no
system or design is better than any other because in the end they are all
prone to accidents at one time or another.

What I find upsetting is that you choose to ignore the fact that both
Airbus and Boeing aircraft are extremely safe even though you are an
intellegent individual.  It seems to me that far to often on this
newsgroup national pride has gotten in the way of common sense.  It's
unfortunate that many individuals on this newsgroup choose simply to bash
Airbus and make it seem as though their aircraft are flying death traps
when indeed they are not.