Re: FLY-BY-WIRE (AIRBUS vs. BOEING)

From:         Pete Mellor <pm@csr.city.ac.uk>
Date:         10 Jul 95 16:37:00 
References:   1
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<aboyd@qnx.com> (Andrew Boyd) wrote on 07 Jul 95 14:26:28:-

>> I can state quite categorically that no *fatal* crash of an A320 due
>> a computer aborted take-off has ever occurred. ...
>
> A friend of mine flies A310s for the military.  He says that 95% of
> the time, you sit there and watch it fly the a/c.  The other 5% of
> the time, you stop it from doing something wrong :(

OK, I'll believe him! :-)

The point about the discussion, though, was what crashed when, where
and due to which causes.

My mailing was meant solely to correct the impression given in an
earlier contribution that an **A320** had crashed due to a computer
aborted take-off. As I said, none ever has. The A320 differs fundamentally
from the A300 and A310, in that it has a software-based "Electrical
Flight Control System" (EFCS). This is what qualifies it as "fly-by-wire".
The A300 and A310 have conventional flight control systems.

Let's just get a few things straight!

1. A "Flight Management System" is not the same as a "Flight Control
   System".

2. The civil aircraft with a digital software-based FCS are (in order
   of entry into service): A320, A340/A330, B777.

3. No crash of any of these aircraft has been nailed to the door
   of the FCS alone (although it has been argued that in some cases
   the behaviour of the EFCS was a contributory factor).

The airliners list ought to be able to get the basic facts straight.
I seem to recall that this is where I came in in 1992, and I suggest
that those wanting to get involved in these discussions should look in
the archives (on ftp.kei.com) first.

Peter Mellor, Centre for Software Reliability,
City University, Northampton Square, London EC1V 0HB
Tel: +44 (171) 477-8422, Fax.: +44 (171) 477-8585,
E-mail (JANET): p.mellor@csr.city.ac.uk
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