The preliminary report is out.
It appears the crew got caught out by a sudden drop in the wind.
42 seconds before touchdown, aircraft was at 500ft, airspeed 150 knots, ground speed 121.
17 seconds before touchdown, aircraft was at 175ft, airspeed 144 knots, ground speed 121.
13 seconds before touchdown, aircraft was at 153ft, airspeed 154 knots, ground speed around 120.
3.6 seconds before touchdown, the aircraft was at 50ft and it’s airspeed was 145 knots (which was 1 knot above their target airspeed). Ground speed was 112 knots.
2.6 seconds before touchdown, the airspeed was now only 136 knots. Ground speed was 111 knots. Bank angle 4.7 degrees. They get a “sink rate” warning.
1.6 seconds before touchdown, airspeed is still 136, ground speed still 111. Bank angle 5.9 degrees.
Less than 1 second before touchdown, airspeed is 134, ground speed still 111. Bank angle 7.1 degrees
Right main gear touched down first at about 3g, bank angle of 7.5 degrees, a part broke in the landing gear and it started folding into the retracted position.
Wing broke off, plane rolled over.
My interpretation:
So the plain didn’t slow down (1 knot) at all relative to the ground, but the wind suddenly died down at the worst possible time, dropping 11 knots (about 20kph). This was after a 10 knot increase seconds earlier. The right bank made it worse since all the weight came down on one set of landing gear. It’s normal to have some right bank in this scenario as the wind was coming from their right, so you need to lower the right wing a bit to counteract the wind. You try to even it out at the last second though. I think with the sudden drop in airspeed which caused a sudden increase in descent rate, they got caught out trying to arrest the descent rate and weren’t able to bring up the right wing.
They went from everything normal at 3.6 seconds before hitting the ground, to losing a ton of airspeed and impacting in just a few seconds.
One of the main questions will be if they should have set their approach/landing speed target higher than 144 knots. This was the correct speed in normal conditions, but they possibly should have set it higher to account for the wind gusts (½ of the wind gust component, which you need to do some math to figure out as it depends on the reported gust speed and the angle of the wind).