"It was established that the a/c had been in cruise climb in the latter part of its approach to the Mull"
NO IT WASN'T!!!!
It was ARGUED by some, using incomplete evidence, NOT a RECORDING which WOULD have ESTABLISHED the aircraft's flight path!!!
It was PRECISELY this lack of RELIABLE evidence that prevented the President of the BOI, from finding any human failings. He said this was due to the fact that it was impossible to recreate the sequence of events leading up to the accident with any reliability!!
Are you getting it yet?