TANDEM - I do not entirely disagree with your post but for me, I see I significant difference in the balance of probabilities between:
1. A serious malfunction occurring at exactly the required moment to cause a crash on the Mull mountain, and;
2. The potential for a crash on the Mull mountain caused at that moment by a combination of poor visibility and airmanship.
I would like to think that a distraction, leading to inattention, to inadvertent IMC causing CFIT is the most probable. However the crew somehow made the decision to fly into a position where this likelihood was able to become a reality. Airmanship plays a role here surely whatever caused the final outcome.
Lack of a FDR or CVR played no part in this accident. Lack of WX Radar probably and almost certainly did.
While there is an argument for both cases, for entirely differing reasons, the lack of radar and avionics must surely be recognised as a contributing factor. In other words, the lack of FDR and CVR would not have been apparent if the radar worked, they used it and responded with appropriate airmanship as the coast approached.
This kind of logic has been lost in the heat of discussion and the dogmatic approach you and others pursue in the light of any intimation that the crew may have been responsible for the final flight path.
As our helicopters have become more sophisticated with many systems providing situational awareness, in offshore SAR and O&G support there is a trend towards downgrading, mentally, the essential role of the WX Radar in identifying and avoiding lumpy bits over the ocean or coasting in. 25 years ago in an S61 with Decca VOR and NDB we placed very high value on the black and white storms cope picture as we coasted in! In this respect nothing has or should change. In my view!