Jayteeto, lest you be in any doubt, I do not think this was in any way pilot error, hence my comment:
"...but until all possible mechanical failures have been exhausted I'd be tempted to give any pilot, and especially this one, the benefit of the doubt."
You are right in saying that no one knows what caused the accident, and I'm glad you accept our freedom to speculate.
My possible scenario (post 1350) is one such speculation based on having read all I can and examined all the pictures I can. The first picture in:
Glasgow helicopter crash: Investigation begins into why chopper 'fell like a stone' | UK | News | Daily Express appears to show separation at the ring frame.
On 6th December, the CAA issued:
http://www.caa.co.uk/docs/33/2013120...D20130289E.pdf
Before anyone asks, I don't know the part number of the ring frame installed in this particular EC135, and it may be just an unfortunate coincidence.
But, like DB, I'd wager that the pilot did all anyone could to control the helicopter and minimise loss of life.