How ski lifts are installed: Vail's new Chair 5 (2011) [video]
Usually tying an in-flight helicopter to the ground is a huge no-no. E.g. there's a subtle sequence of steps for airlifting a casualty from a steep hillside that prevents the helicopter from ever being connected by a rope to the ground (the reasoning, AFAIK, is that the helocpter migth need to depart or move at a very short notice and the line may hinder it and injure people if it breaks).<p>It seems that there are reasonably long period of time here when the helicopter is still connected to a tower segment when the workers are in the process of screwing bolts in. Why isn't this problematic?