you usually use that calculation to make an idea of a possible RVR, but if it's not officially reported on the METAR/ATIS you cannot use it for landing decision.
Offcourse not. I mean if the RVR equipment is U/S and the tower reports Visibility you can convert it to RVR and land!
I've always known that if (for CAT I ILS) you need RVR =/+ 550mt or 800mt VIS
Where can you find this? I looked in JAR but I cant find this?
and you're only given VIS=400mt, then you're supposed to continue the approach whilst still under the minimum, but then you must go around at the OM.
The general rule is that the most restrictive condition is the one that you must take account of.
Here I convert 400 times 2 (because I have night and HI intensity approach lights. Equals 800 meters RVR, so I can land!
Regarding the VOR approach, I've never known the ceiling is only for planning purpose. Anyway,why should that be? If you have BKN003 and the MDH is 420ft you will hardly be able to seethe runway land since you are at the minimum and have 120ft of clouds under you.So you cannot go lower than 420ft and should go around again...
Where do you find this? Yes Broken is a cieling but if I come in and they are reporting BKN003 its a big chance that I will not see the approach lights etc. but if I do I can land! Because the only controlling when Im in flight is the Visibility (RVR)!!!