[ArrogantBustard]

Why do the prop blades look feathered in that pic? Is that how they are kept with the engine off?

Yes, and Yes.

This aircraft uses a PT6A free turbine engine. There is not direct mechanical connection between the hot gas generator section (wherein fuel is burned) and the power section (which drives the prop. With the engine off, there is nothing to prevent the propeller from freewheeling in the wind. I'm actually surprised they don't have a boot on it. That's standard practice with some other PT6A powered aircraft, such as the Twin Otter.

[linear]

Thanks - that explains it.

Wouldn’t you want some sort of internal lock, to stop them from freewheeling in the air if power is lost? Would help the glide distance I imagine.

I’m a turbofan guy myself (CF6-60) so modern props are a bit of a mystery to me.