In the news

800 is typical at that point and approximate. No reason whatsoever why the planners should get any heat, a NOTAM had been issued so the pilot should have been aware. Of course if the pilot had only checked for NOTAMs on their planned route and not on the diversion... But I'm speculating now. Doesn't change the fact the copter shouldn't have been anywhere near as close to the building as the crane was.

As you say pointless to speculate but read some 'eye witness' accounts and they said the helicopter looked 'out of control' before it hit the crane.

But who knows. I do know the visiability was shit as I can normally see the tower for a fair bit of my commute but could hardly make it out today (I did look as I'd seen the news before I'd left).