Not to judge, just to say what I see/ saw: Looks like oscillating bounces followed by a gear collapse an/ or loss of control causing the aircraft to hit the ground with its left wing and roll. Amazing though that it pretty much slided on its back and did not roll further. Notice the nose, right main and centre gear pretty much still there on the pictures.
As a former FedEx employee, my condoleances to the relatives and friends of the pilots.
Ptt,