Hi STBYRUD,
maybe with not enough opposite aileron
They both had full opposite aileron - but even that wasn't enough because:
From page 46:
The aircraft
touched down shortly after the 1,000 ft marker in the touchdown zone, about 2 m left of the runway centreline lights
with the left wing 4° down and the fuselage pointed 2° to the right of runway allignment, whereupon the rudder pedals were returned to the neutral position.
The aircraft yawed towards the left, thereby increasing the lift from the right wing and decreasing that from the left wing. In spite of the co-pilot's right sidestick correction, this resulted in unintended contact between the downwind main landing gear and the runway. The objective had been to land with wings level. This was confirmed by the correct application of right sidestick prior to touchdown, which was intuitively supported by the Captain's sidestick (dual input).
After touchdown the aircraft yawed a further 5° to the left. The left main landing gear lost contact with the runway. At no time did the right main landing gear make contact with the runway. Lift dumpers (partial spoiler extension) remained inactive, because the necessary prerequisites were absent.
During the next few seconds
the aircraft rolled to a 23° left wing down attitude in spite of the full right deflection of both sidesticks and application of right rudder.
The switch to Ground Law limited the effect of roll control corrections. The left main landing gear again made contact with the runway. At about the same instant, the left wingtip made contact with the runway.