We change when the ceiling drops below 200 or we get numerous missed approaches because of the weatherskypirate88 wrote:
At what point does the decision get made to switch to CATII operations? Does it impact the operation that significantly if an aircraft requests such an approach?
CAT1 ILS vectored spacing is 2.5-3miles in a dedicated land and 5-6 miles in a mixed mode
CAT2 ILS is 8-10 miles dedicated or 14-16 miles mixed mode
The reason being in dedicated the arrival must have exited the runway and be established on the parallel taxiway by the time the next arrival is at 4NM final, in mixed mode the departure has to have overflown the localizer by the time the arrival is 4NM final
Where a CAT1 approach the arrival needs to be off the runway pavement by the time the next arrival is at the threshold and in mixed mode the departure needs to be rolling when the arrival crosses 2Nm final