TR, like tuc, I do not claim that airworthiness (or rather the gross lack of it) caused this accident, simply because we don't know what caused this accident, and that primarily because it has never been properly investigated. The main reason I say that is because the BoI never considered the elephant in the room:
the appalling state of the Mk2 in Jun of 1994
You tell us you knew of the many problems of the HC1 and the HC2, and so did others, such as the RAF Odiham Station TP, yet no-one gave evidence to that effect or was even called to give such evidence.
Perhaps the most damning issue though is not of investigation, but of avoidance in the first place. If, as tuc says, the Airworthiness Regulations had been properly adhered to, as is required by Military Law, then the HC2 would not have been granted an RTS, would not have entered service when it did, and ZD576 would not have ended up splattered across a Scottish hillside. In that way at least, TR, we can be certain that airworthiness was a major factor in this accident. I admit that I suspect it to be more than that but I cannot prove it. Many accident causes cannot be completely proved, but are the most likely cause as determined by the investigators. Ironically Gross Negligence is possibly a just finding in this case, it was merely laid against the wrong people!