Just to clarify, I don't have a civ IR but do have a mil one with several hundred hours IF under my belt.
It appears to me that the crew of the AW139 were faced with a choice; IFR or VFR?
It seems probable that they couldn't 'legally' depart VFR as, in the UK at least, a minimum visibility of 3000m is required.
An IFR departure was legal, according to my understanding of the ANO Rules 32 to 34. However, the inference I get from this thread, given their non-mil background, is that they probably had little or no initial or recurrent training in the necessary techniques.
Is it reasonable to assume that 'zero/limited' vis take-offs are occasionally carried out, quite legally, on Private category flights by potentially 'untrained' crews? Given that the required technique isn't brain surgery - the mil do it - but it is a skill that requires careful instruction and recurrent training. Is their not a case for including it the civilian IR syllabus and recurrent IRTs?
JJ