AnthonyGA:
Combine this with the extremely poor record of reliability for software engineering as a whole, and software becomes a considerable cause of concern.
I'll refer you to some older posts I made on earlier incidents, because I don't want to go round the houses with it again, but the gist of it is that the software engineering discipline for real-time safety-critical systems cannot be compared to any other type of software engineering in terms of reliability and testing.
http://www.pprune.org/rumours-news/3...ml#post4321101
http://www.pprune.org/rumours-news/3...ml#post4046089