If I may put my 5 cents worth in (used to be a penny)? There is a general misrepresentation of the colloquial term 'cosmic rays'. Did I say anything about the 'media stock phrases and cliches' handbook? Wash my mouth out!
This discussion concerns high energy particles, and a reading of
Cosmic ray - Wikipedia, the free encyclopedia will bring one up to speed.
They are singularities, and although they can occur in 'showers', read high_incidence_of, they *are problematic, and how much so depends on each individual particle's very variable energy level. They are not just a threat to electronics, but also to DNA and indeed any of your cells.
On the well _known _in _the _trade basis that such an particle can 'take out' an individual electronic component, whether temporarily if low energy or sometimes permanently if high energy, any problem should be an isolated event that can in no way known to wo/man be specifically guarded against, short of using lead wrapping on all boxes.
As another ancient here says, the design must fully guard against any individual failure.
On a related matter, here’s snippet of information related to Airbus’s design philosophy. I haven’t seen this mentioned since my engineering course on the second lot of free range A320s. (Gosh! Have they been flying for *that long.) It was stated then that Airbus went to what I would have thought were excessive pains to diversify the build parameters and supply sources of all duplicated equipment.
We were told by an Airbus rep that duplicate suppliers were given design parameters which they were free to achieve electronically anyway they chose, but obviously to tight aviation constraints. The ultimate black boxes. The idea was that a *design flaw in one element of the control architecture would be isolated to one item in the control chain by default.
To the best of my recall this philosophy was applied across the entire airframe, and I have been surprised at reports that certain Airbus aircraft have finished up flying with all pitots from the same manufacturer. That certainly was not the original designers' intent.
No doubt the cost of extensive duplication of non-identical but similarly functioning components has attracted the attention of the financial fine tuners. <sigh>
(Written from the future as this appears, the comment re pitots seems rather relevant to the current (20100820) threat mulling the AF447 loss. Amended by Jencluse.)