dalek is spot on.
All descriptions of the minutes leading up to the first impact of ZD576 with the Mull of Kintyre are based on models of what may have happened. Not records of what did!
The BOI's version of events is a hypothesis, not a fact.
The president of the BOI accepted this. He said so at the Fatal Accident Inquiry, and that is precisely why he was unable to make a finding of negligence.
Of course others seemed more keen to overlook the limitations of the 'modelling'.