Single - You're absolutely right. The touchdown and mid-point RVR are controlling, withthe rollout being required, but only as an advisory. So, 600 - 600 - 0 would be perfectly legal.
Snoopy- Yeah, I've never really seen the logic in it either, but that is the way it is. If we are doing a CAT I ILS with an 1800 RVR requiredf vis, and after the FAF the reported vis goes below 1800, we can continue to DA, and if we see any of the reuired stuff, and the flight vis is above landing min's, we can land. However, under our CAT II/ III program, if we need, say 600 RVR to start the approach, and once inside the marker the reported vis drops below 600, we can continue to DH, but can't land unless the reported vis increases back above 600.
This is due to the 717's not having a 'rollout control system'- ie autobrakes.
Either way, kind of goofy.
Snoopy- Yeah, I've never really seen the logic in it either, but that is the way it is. If we are doing a CAT I ILS with an 1800 RVR requiredf vis, and after the FAF the reported vis goes below 1800, we can continue to DA, and if we see any of the reuired stuff, and the flight vis is above landing min's, we can land. However, under our CAT II/ III program, if we need, say 600 RVR to start the approach, and once inside the marker the reported vis drops below 600, we can continue to DH, but can't land unless the reported vis increases back above 600.
This is due to the 717's not having a 'rollout control system'- ie autobrakes.
Either way, kind of goofy.