Nick,
If I remember correctly in the case of the UK military Chinook there was a slur. The families hung their heads not because the report found that there was a human factor involved when there was no particular evidence one way or the other, but because the pilots were found guilty of Gross Negligence without any particular evidence of human factors one way or the other. I note that, long after many horses have bolted, CVRs are now being fitted in UK military aircraft
The fact remains, on the UK side of the pond (in the 80s I think) an S61 crashed in fog but with bright sunlight which may have masked the little orange light on the radalt. As a result, all those years ago, an audio warning (AVAD) was mandated by the UKCAA. This goes off when the bugged height is reached and at 100ft, so even if the crew fail to set the bug they still get a 100ft warning in their headsets. It is not a full blown EGPWS, but it has the effect of advising the crew that something is amiss when flying offshore. Why did this not get adopted on the other side of the pond? Maybe no one took the time to take an interest in accidents outside the USA, or maybe it was a criminal attempt to save money. If the FAA had made AVAD compulsory on all offshore helicopters I am sure several lives would have been saved over the years and this accident may have been avoided.
Has this lesson now been learned?