etrang - layers of ice that are deposited in successive updrafts through the CB, I believe.
The policy in accident analysis and incident investigation in the last few years has been not to seek to blame people - who rarely deliberately jeopardise safety - but to identify the systematic problems that allowed the accident or incident to occur. The pilot is usually simply the last link in a whole chain of events any of which could have been broken and the incident/accident would not have taken place. Of course the pilots - particularly the skipper - have to bear some responsibility - they are the ones who sign the tech log - that's what their licence is for. But the aim is to stop things going wrong in future, not work out who was to blame in the past so that you can sue them. This has become the attitude of conscientious regulatory authorities (who are much more concerned these days about corporate responsibility than they used to be) and safety departments in airlines (who realise that the most important thing about accidents is that they don't happen again).
The fact is that anybody could be put into a simulator and made to crash an aircraft - anybody - including the ace-of-the-base pilots who have seen fit to second guess what happened in this incident. So yes, there but by the grace of God go you - the day you stop learning is the day you die - and you are only as good as your last flight. You read accident/incident reports to learn, not to blame. And if you haven't got hold of that fact yet, you don't deserve a third stripe, let alone a fourth.