Waypoint change was only 600m from nearest shore.
They would have had to have turned left a few miles earlier to have a straight run to B while clearing the higher ground further up the Mull.
Neither the SuperTANS as a whole nor its component GPS on its own back in those days would have been considered reliable enough to have got that close at that speed while still heading towards the high ground.
The weather on the Mull was such that visual judgement of range would have been impossible to any degree of accuracy or certainty and in that respect their approach VFR would have been very wrong without some kind of electronic range measurement – and they did not have radar.
They did not simply fail to turn left, they actually turned right onto a track reflected in the handling pilot's HoSI and the altimeters were set so as to facilitate a close pass over a known LZ – and neither the a/c's attitude nor the engine states suggested anything other than cruising on straight and level until seconds before impact.
Whatever you say about the a/c's airworthiness, either they were negligent before waypoint change or they were using some other kit thus far not officially acknowledged – this argument led me to pursue candidate systems and eventually CPLS popped up.
I have given you on a plate a line of inquiry that could not only clear the pilots' names but also get real justice.