I was amazed to find this video clip of an AS332 Super Puma helicopter of Airlift AS in Norway. It’s using a specially-built multi-ton underslung wrecking ball, suspended from a very long line, to knock down unstable rock formations on a cliff overhanging Highway 70, a Norwegian coastal road. According to the subtitles, multiple rockfalls had blocked the road over a period of a year or more, so it was decided to remove as much of the unstable rock as possible to prevent further rockfalls.
I recommend watching the video in full-screen mode.
That’s pretty remarkable flying. If you watch helicopters with underslung cargoes, they typically try to avoid oscillations or uncontrolled swings at all costs, as these can render the aircraft unstable – even unflyable in a worst-case scenario. This crew had to do the opposite – deliberately encourage oscillations by swinging the wrecking ball, but not so much that they tugged the helicopter out of control. It must have taken a fair bit of trial and error, and a lot of skill, to get it right.