John Blakely,
Thankyou, Sir, for a most courteous and informative reply.
The comments regarding the weather being poor as well as the aircraft being unable to climb to MSA came from an Ex Naval Officers fertile mind. We must, however, face the fact that the Aircraft did not climb to MSA or turn away from the high ground in its path.
There does not appear to be any evidence of an aircraft malfunction so severe as to preclude the flight deck crew from concentrating on the primary task of flying the aircraft and ensuring its safety; or a malfunction which physically prevented them from so flying the aircraft. There was no distress call or attempt to squawk "EMERGENCY"; either of which would have alerted SARSAT.
One possible explanation could be distraction from the primary task by visitors to the flight deck or an unusual occurrence in the passenger cabin. Many years experience as a Comms Fleet Captain ingrained the potential danger posed by such distractions; particularly on crew members unfamiliar with such happenings.
One thing that we do know is that they had a potential major problem with Crew Duty time; particularly as they would need approval from HQNI to nightstop outside Theatre.
One other factor is that the BOI concluded that during their first task the crew would have been unlikely to have had anything to eat other than a few biscuits. Although the Co Pilot and the ALM's had Breakfast in their respective messes, there was no record of the Captain doing so. At the very best no member of the Crew had eaten a proper meal for some 10 hrs when they took off on that fatal sortie. One wonders whether low blood sugar levels could have had an effect on decision making processes.
My thanks once again for a most informative reply.