I saw the clip on trhe late news Sunday night (early Sunday afternoon in UK, earlt Sunday morning in US).
I hadn't seen this post, so I posted about it, sorry.

But.............all my sympathy to the relatives and friends of the two crew. 

They said the film I saw was a reasonably 'good' amateur video. The authorities are studying it to see if they can figure out what happened.

The clip I saw was about 10 seconds.
The plane was not approaching to land (at least from what I saw), it was doing a manoeuvre. It went up for a loop, inverted at the top as usual, when on the way down it rolled 180 degrees as if to do a 'figure 8', but suddenly the plane rolled back the right way up and seemed to 'rock' on the aelerons a couple of times.
It went into the ground pretty much on it's belly.
It looked to me as though it stalled and dropped into the ground. As though it was going downwards faster than it was going forward, while sitting level - a stall, as far as I know.

Anyway, whatever the case, it's a tragedy!