I came across this story earlier today. This is indeed sad that this has happened. We tend to forget that on planes and helicopters there is a spinning "meat cleaver" that can do some very serious damage to people, or even kill them. I learned that myself a few years back when my hand got tangled up in the prop and I wound up with 30 stitches in my hand. It only took one second of not paying attention (I was starting the plane on the runway and it moved forward and out of habit I reached out with my hand to stop the plane, and got my hand tangled in the prop) to have my hand in the prop and caused some serious damage. I was lucky that it wasn't anything serious like the tendons and was only in the fatty parts of my hand, so the stitches fixed everything up. I don't know what happened here in this accident, but I'm sure the details will come out soon.
My heat and sympathies go out to the family of this young man.
Ken