We will never know
Cazatou,
Your last sentence is the reason for this thread's existence - if your question could be answered we could all go home - but it can't and because it can't they should never have been found guilty of the equivalent of culpable homicide. There are any number of things that could have gone wrong - some even written up in the RTS - why do you never consider what the effect of these might have been rather than assuming that the crew effectively committed suicide by flying towards high ground instead of making a small and easily achievable, in the time and distance, left turn on to the new course?
How do you know they did not try to transmit an emergency call? As I recall the IFF squawk was 7760 - close to the emergency one of 7700 - was it being changed at the point of impact or was this the last squawk requested by Belfast? In my limited basic flying training I was always told that the first thing to do in any emergency was to fly the aircraft (assuming it to be flyable at that point) and not to worry about the radio etc until afterwards, and in two real Pan calls later in a Lightning and Tornado that was exactly what happened - with no emergency call from the captain until the offending engine had been shut down, the emergency FRCs had been checked and we knew what we were doing.
Why not start by assuming the pilots knew what they were doing, had a good flight plan and were following the rules and procedures to the letter, and then look at the options for something else going wrong with the aircraft, and see what you might come up with! At least then you will have done something the BoI patently failed to do.
BTW - just to remind you, the AAIB report effectively covered all options as far as mechanical flight control systems malfunctions were concerned - see below:
43. Almost all parts of the flight control mechanical systems were identified, with no evidence of pre-impact failure or malfunction, although the possibility of control system jam could not be positively dismissed.
44. Most attachment inserts on both flight control system pallets had detached, including the collective balance spring bracket that had previously detached from ZD576’s thrust/yaw pallet, with little evidence available to eliminate the possibility of pre-impact detachment.
JB