The slats are actuated by hydraulics (G&B) and move to their required position along tracks, so as to follow a predesigned curve while extending.
The mechanical transfer is done through a rack and pinion mechanism along some of the slat tracks.
I can imagine that under the worst set of circumstances (end-travel sensor failed, hydraulic valve block damage, etc) the slats could be pushed outwards beyond the last extended position, resulting in the position sensor >3 and some crooked slat position.
That would be a bad day, since with less slats, most pilots can guess what the aircraft behavior can be, but with more slats (and by how much?) , flow separation, aircraft behavior, and low speed characteristics would definitely be situations with unsure outcomes.
Could it be what the table presented tries to address?
Last edited by Jetdriver; 31st July 2013 at 14:09.