Although our ILS's are shielded, we still radiate one ILS only. I guess the authorities here are afraid that a pilot might select the wrong frequency and hence the restriction over here. Our ILS's are also designed in a way that you cannot select ILS's for the same runways , say 12/30 or in your case 27/09 at the same time. You can only select 09 or 27 , but not both together. We can however in conditions of vis better than 3000 meter radiate two of the 4 ILs's and they should be and can only be in our case 12L and 30L or 30R and 12R. We may under no circumstances radiate 12 L and 12R and 30L and 30 R at the same time! Our parallels are only 300 metres apart, maybe thats why we have to do it. Our spacing in CATII or III is 20 nm in trail, provided there is no departures and 30 nm in trail if the Tower wants to insert a departure in between. No intersection deps are permitted - full length only. Because the runways are so close, we suspend parallel rwy ops when vis is below 1500m and use a single rwy. My guess again is that the all these restrictions are due to poor airport design and no other particular reason that I am aware of. It is a major disruption to all operations in CATII/III as you know. Our legislator also has an approach ban policy requiring the RVR to be 350 m or greater before the aircraft reaches 1000 ft(3nm) on the approach before it may continue (CatII).
Hope it helps?
Cheers
Fart
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