My other half and young daughter landed in Glasgow a couple of days before, from Canada. You just can't plan for these outcomes and it's terribly unfortunate for the occupants of the coptor and indeed... for it to land in a packed pub playing live music.
I've not heard whether they've found out the cause of the crash yet, only that the blades weren't turning and it's been suggested it was out of fuel since there was no fire... though I've heard by design (thankfully) the fuel tanks are more hardended than the rest of the vehicle.
I am also from the West of Scotland. The Clutha Vaults is not such a large place and it was house full on Friday night. If you can imagine a small area like this jam packed with people I think we have to be thankful that it was not much worse.