THE WEATHER
The ironic thing about the weather is that by all accounts the weather affecting this a/c was generated by a fixed feature and is very common at certain times of the year
so you could have spent some time up there and got a feel for what the Mull most probably looked like as they approached it then perhaps you would understand the idea that you can see it from a distance but judging closing range would be very difficult at speed but to actually make the effort to go there seems too much for most of you anyway, it would be like reading the last page of a book that you like guessing the end of ...
HPT
It wasn't in route steer mode the change was made manually.
Regarding the other information, I am grateful for your thoughtful reply which has made it clear that there are some (understandable) misconceptions of what navigation system (or combination of such) the HoSI works off when you select TANS on the mode select panel, and for that matter how the suggested angle of bank (to get a nice turn onto the required track) is derived that is displayed by a pointer within the AI.
I suggest you (and anyone else interested in the navigation systems aspect) brush up on your theory and we try and get an agreed whole system description on the open forum don't delay for fear of minor errors, get on with it and doubtless others will correct it until we have an agreed understanding of the navigation systems (and the presentation of their data to the pilots) available to them when I get some more time, I'll kick it off if no one else starts first. Nothing secret here, forget CPLS for the moment, just the old Doppler and GPS systems, air data, etc, integration and display, etc basic stuff.
I do respect that you put forward your understanding very few on the thread have been willing to be open, preferring to put it in the too hard box.
Regarding the CPLS you state confidently that the RAF does not use it for navigation meaning, I take it, that it is not used for, say, approaching an LZ in the conditions I described, despite its use like this being a recognised attribute elsewhere further, very few here would touch the subject with a barge pole I can think of a good reason for this odd attitude towards a useful piece of kit
this crash.