OK, can anybody fully qualified to answer, explain to me what we (think to) see in the picture of the S-shaped skid marks ? These are the last 2-300 metres, so speed being quite low and then managing (surely while overcorrecting) a 90° turn onto and over the runway. As breaking action (and directional control) on the grass must have been poor, what speed would he have had when crossing the runway (from LH grass to RH grass)? And any pilot on top of the situation, wouldn't he be able keep the ac more one the runway (differential braking). My (untrained-unqualified) guess would be that during the roll on the LH grass, nosewheel steering would have overcorrected, but while on the grass without much effect, until on the concrete when the nosewheel regained grip making the plain turn sharply? The initial exit on the LH grass was only 10-20° off track, so how comes one can overcorrect so much to the right?