Didn’t Bristow have a Puma do that on a rig offshore Malaysia years ago? I think Okanagan had an similar event with a Puma or 61 many moons ago. Both where shutdown at the time and vicious line squalls ruined the day.
I recall both resulted in rollovers.
Saw some photos of both events.

Yes - not new at all.

https://cimg9.ibsrv.net/gimg/pprune....456db28d05.jpg
Always wondered if the machine would fit on the back of one of those....well now i know.

That depends on the reference frame

Pretty sure it doesn’t. CF is an inertial, or pseudo force

If the unrestrained blades started turning by themselves in response to the storm's winds, would this phenomenon be classified as "Ottorotation"?

Only if the engine would self ignite due to compression

:D bravo sir

I have a video but it’s a .mov file - anyone know how I can upload here?

I doubt if you can.

Your best bet might be to upload it to YouTube then link to it from here.

https://vimeo.com/804386419

Ouch !!. It seems strange that, having shut down, if the pilots considered it necessary to tie the airframe down due to strong winds, they didn't tie the blades down.

Not really. I once had a shutdown on he Beryl "A" when a ferocious wind blew up. I crawled around the deck lashing the S61N aircraft down but there was no way I could have tied the blades down.

The rotors never stopped turning, so trying to 'catch' and tie down blades in those conditions would have been extremely hazardous.

thanks for confirming what I thought. What’s curious is how quickly the winds developed. Given the storm had a name, it wasn’t a random squall.

Goes to show what a crap rotor brake is fitted to the H175.

And the 2 guys trying to lash it to the deck in the video wasn't hazardous? How one didn't get hit by the broken blade I do not know.

HSE are going to love this one.

A couple of questions if I may. Was the aircraft shut down within the RFM wind limits? Having shut the engines down, did the rotor brake fail?

I think outside but they had a TGB chip light. The brake couldn’t fully stop the blades.

Shutdown was within limits, but the rotor brake on the 175 is poor, and couldn’t stop the wind from rotating the blades. The blade tie downs on the 175 are of the tip sock variety, so trying to get those onto rotating blades that are already flapping in the still-technically-in-limits-but-rapidly-increasing wind would have been impossible. They tied the airframe down and then evacuated the deck as it was getting too dangerous. Not sure of the actual wind speed by the time the video was taken.