Mr Purdy, your use of the words 'assume', beleive', and 'theory' illustrate that you have yet to grasp the thrust of our argument.
Archimedes has very eloquently put our case.
Consider why the regulations required that gross negligence would need to be proven 'with absolutely no doubt whatsoever' where dead aircrew were implicated.
It was precisely to protect such unfortunates, with no defence counsell, and no recourse to appeal, from the 'assumptions', 'beliefs' and 'theories' of others.
Put another way, in the absence of absolute, positive and incontrovertible proof that a certain chain of events and actions actually caused an accident, no finding of Gross Negligence could be arrived at. The benefit of the smallest doubt rests with the pilots, and makes the finding plain wrong. This is the point made by their lordships.
We could theorise until doomsday over what did cause the accident, but we will never know 'with absolutely no doubt whatsoever' what did. It is, anyway, irrelevant to this campaign.
Negligence is something which must be proved beyond any doubt whatsoever, not just used as a convenient cause when no other can be found.