Min visibility for departure in LVO's
I wonder if you can share some information on the minimum required departure visibility in Low vis operations.
Recently our CAT II has been downgraded to CAT I due to LOC interference and I was just wondering if that would chnage the min vis requirement for departing aircrfat from the airport in low visibility conditions. In a CAT II situation, the min required vis was 125 m and if the TD RVR fails, then it increases to 150 m and both mid point and stop end RVRs must be serviceable for a rejected take-off. Now, in a CAT I situation, the normal RVR for landing is 550m and I must assume that in order to depart safely, the min departure visibility must be 550 m in the event that the crew has to return for an immediate landing after take-off in an emergency. If the dep. vis is less than 550m and you are allowed to depart, does it require a take-off alternate which must be within a short distance/time away?
Do you expect controllers to protect the ILS sensitive area when the vis drops below 600 m and 200feet? Our CAT I holding points are within the sensitive areas and the question is whether it is permisable to hold aircraft at the CAT I holds when there is arriving aircraft on the approach? Using the CAT II holds will obviously take care of the situation, but it requires additional spacing on final between arrivals in order to get a departure away. You are probably looking at a min 15 nm in trail distance between arrivals if a departure is inserted in between arrivals.
Any information on low vis ops would be appreciated.
Thanks
Fart