Bringing back the big picture, Messrs Wratten and Day had to satisfy the requirement of "absolutely no doubt whatsoever", to determine that the crew were negligent. This differs greatly from the mere assumption of negligence proposed by JP and K52.
To use an old worn analogy, if you are driving along a straight road approaching a 90 degree bend and for some reason you fail to turn, are you negligent? What if the steering failed, are you negligent then? What if you suffered a blow out, are you negligent ? What if there was no evidence of any malfunction but several suspicious and incongruous indicators of problems, would anyone be certain beyond any doubt whatsoever that the driver was merely at fault? Are you negligent because you chose to drive down that road?
There are too many uncertainties with this tragedy to categorically establish that the crew were negligent beyond any doubt whatsoever. JP, from your last post you surely have to concede this point in that you also are unsure as to why they did not turn away. This, even though you have your own theory as to why, clearly does not satisfy the unbelievably stringent standard of proof of no doubt whatsoever. That you, or anyone, has no real evidence of why the crew did not turn away is sufficient to have rebutted this stringent burden of proof. At best there is hypothesis and conjecture, but bearing in mind the presumption of innocence and benefit of the doubt, there is no way this judgement should stand.