Interesting to see that after an absence from these pages of over a year the argument is still going round in circles.
As Uncle Peter sates Messrs Wratten and Day had to satisfy the requirement of "to determine that the crew were negligent.
The only ones who know exactly what happened that tragic night are sadly dead and no amount of specualtion is going to provide an answer to satisfy the requirement of absolutely no doubt whatsoever as to the cause of the accident.