[SystemSafety] Technical information on Airbus A320 recall?

[Derek M Jones]

All,

> A final word about FlightGlobal's comment about "thermal neutrons." I take it with a grain of salt that people think 
> they know what primarily causes SEE in the atmosphere at altitude. I looked at it pretty hard a couple of decades ago.

Cosmic rays are an established cause of bit-flips in memory and
less often in cpus.  See section 6.5 "Non-software causes of unreliability"
of my evidence-based software engineering book for references and data.
The pdf can be downloaded here http://knosof.co.uk/ESEUR/

Speculating about what impact a software change can have on
radiation induced corruptions.

A big flip will cause a value to increase/decrease.  A partial
mitigation for this is to perform more range checks on values.

I have always found it surprising that a large percentage of
radiation induced corruptions have no external visible impact
on the behavior of software.  See book for details.

-- 
Derek M. Jones           Evidence-based software engineering
blog:https://shape-of-code.com