I am indeed reluctant to engage Walter further here and am making yet another attempt to get the mods to split off his 'theories' to another thread, BUT, for Walter:-
Would you agree that it would be essential that a 'plot' of the nature you propose would not be discovered? The political fall-out would be enormous if it were. Start, therefore, looking at 'probilities' of success for it. I would venture to suggest that anything less than 99% would not be considered?
a) You need to ensure that the weather en-route is fit for a LL transit to INS.
b) You need to ensure that the Mull weather is such that the 'normal' upslope stratus allows a LL approach to the Mull BUT covers the hill at and below the LZ elevation.
c) Likewise, there must be NO possibility that should they descend to stay in 'contact', sight of any feature such as the lighthouse, the coast or whatever would trigger doubts in the crews' minds.
d) You need to ensure that the crew carry on in those conditions toward rising ground, without sufficient visual clues and at 'high speed', towards an LZ they cannot see, do not turn around, let down over the sea and 'creep' in to the LZ, thereby blowing the lid off the whole thing.
e) You need to ensure that the ensuing impact is of sufficient violence to kill the crew and pax and render a technical investigation difficult.
f) You need to ensure that no 'survivors' know of the plan, as it appears to have been un-authorised and 'unknown'. Who tasked it? Did the crew get a phone call in the Mess the night before? Did one of the pax tap them on the shoulder on the way over and say "hey, can you have a go at this"?
At best, I arrive at around a 5-6% chance of success. Not good enough? Why would anyone take that risk? Credible? No, Walter, I'm afraid not.