I read a survivor account, as reported in the media today. She reported that the aircraft became airborne, abruptly dropped a wing, suffered roll oscillation and then landed heavily and broke up.
Having not read this thread before I have skimmed through and note:
1. Someone posted that the wing LE devices appear to be in the retracted position.( this from a photograph which I have not seen)
2. There is speculation that the pre departure rectification work could have disabled the takeoff configuration warning
3. It is reported by survivors that the Captain talked ( via PA?) of an unexplained warning light.
In my experience, it is essential, under conditions of disruption such as a return to the gate and/or maintenance rectification, that checklist discipline is strictly followed. Is is easy to overlook items, or falsely 'remember' that they have been completed, under the stress of a non normal situation.
From the survivor description sounds as if the aircraft entered a stalled condition after climbing out of ground effect. If the LE devices were not selected ( maybe the Captain saw a visual warning that they were not set, but was confused by not getting an aural warning?) and takeoff was commenced, rotation would start at the normal point, but the aircraft would not get airborne until a considerable distance afterwards. After a late lift off and climb to low altitude, the wings would stall as they came out of ground effect, leading to loss of lift and the observed roll oscillation.
Then assume the crew, having a fair distance of runway left, tried get it back down, touching the right wing as they do so. The priority would be to stop asap, so it would be natural to apply max brakes and reverse. That would explain the reverser deployment and runway skid marks. Loss of directional control would have lead to the break up and fire, in the drop off to the right of the runway.
This scenario would not have been helped by an engine failure or uncommanded reverser deployment in the air,of course.
This is, as are all these posts, speculation but appears to fit the facts as so far described.
A terrible accident which serves to remind us all how quickly the routine can turn to disaster, in a moment. Condolencies to all who lost family or friend in this.....