[SystemSafety] A small taste of what we're up against

[Peter Bernard Ladkin]

On 2018-10-26 10:14 , Dewi Daniels wrote:
> On Wed, 24 Oct 2018 at 10:26, Martyn Thomas <martyn at thomas-associates.co.uk
> <mailto:martyn at thomas-associates.co.uk>> wrote:
> 
>     I'd like to see an ALARP argument for software written in C. Does anyone
>     have one to share?
> 
> There are over 25,000 certified jet airliners in service world-wide, many containing software
> written in C. There has not been a single hull-loss accident in passenger service ascribed to a
> software fault.
True as far as public information goes, but there well could have been. QF72 in October 2008, and
the other incident in December 2008. Also the upset to Boeing 777 9M-MRG in August 2005.

Concerning SW involvement: a test A330 was lost in June 1994 in part because of a loss of critical
flight information at high angles of attack in the then-design. There is arguably software
involvement in other fatal accidents.

It also depends on what you consider to be a "software fault". When software behaves according to a
requirements specification which leaves a behaviour open which leads to an accident, then some
people would call it a software fault (because the software behaved in an unwanted manner, causing
the accident) and others would say there was no software fault (because the SW behaved according to
the requirements specification).

PBL

Prof. Peter Bernard Ladkin, Bielefeld, Germany
MoreInCommon
Je suis Charlie
Tel+msg +49 (0)521 880 7319  www.rvs-bi.de





-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: OpenPGP digital signature
URL: <https://lists.techfak.uni-bielefeld.de/mailman/private/systemsafety/attachments/20181026/c6fa2e2b/attachment.sig>