Re: OT?: AF 447 and avionics software

[Martin <martin.dowie@btopenworld.com>]

On Jun 4, 10:29 am, "Alex R. Mosteo" <alejan...@mosteo.com> wrote:
> I'm sure most of us are following the news on this issue. I just read an
> article where an 'expert' questions "damn computers". Particularly this
> quote:
>
> "In these fly-by-wire systems, one never really knows if one has checked out
> all possible combinations of events to make sure that the computer properly
> reacts,"
>
> http://www.time.com/time/world/article/0,8599,1902421,00.html
>
> Frankly I know nothing about the aviation standards for software/computer
> use, but I suspect it is somewhat more strict than "one never really knows".
> I mean, surely you can't test everything, but I guess one can be reasonably
> confident on the system design!
>
> Now, there's a trend forming pointing to the ADIRU [1] unit, because of
> recent incidents like the Qantas flight mentioned in the article. I'm not
> sure there's really verified reasons to point to it yet but, trying to stay
> on topic:
>
> I think Airbus is mainly Ada, right? Do you know some good place to read
> about its software systems?
>
> What about these ADIRU units, are they delivered to Airbus by some provider
> or are of their own built?
>
> [1]http://en.wikipedia.org/wiki/Air_Data_Inertial_Reference_Unit

They can analysis code to ensure absense of runtime error (e.g. using
SPARK and/or tools like PolySpace) but testing all possible scenarios
is a different kettle of fish all together.

The systems may even do everything that was required of them but how
do you 'test' the requirements are 'sensible'?..

Cheers
-- Martin