Brian
I regret, Bast0n, that it is not fact. You cannot say with absolutely no doubt whatsoever, that the Chinook was serviceable prior to impact.
No I did not say that it was or was not serviceable. I was just getting down to the basic fact that the aircraft - in fog - flew into a rock. As in all things in life there is no absolute certainty. There are however very strong probabilities. The probability that I was espousing was that had basic DR nav been followed, what ever happened/did not happen in the aircraft in those last few minutes it would not have been so close to the Mull for it to have struck it. It may have fallen in the sea, it may have recovered to controlled flight - any one of dozens of possibilities. I like your reasoned replies and I wish you all the best.