Originally Posted by
moggiee
375m VISIBILITY or 375m RVR? There is a BIG difference.
If a measured RVR is not available then the "equivalent" RVR is calculated by multiplying the measured met vis by a factor of 1.5. So, 375m VIS becomes a factored met vis of 562m "RVR" (equivalent). But if the measured RVR was 375m then that is a different story.
As for cloudbase, the acceptable minimum on an ILS approach is 0'. Therefore, the only weather criterion that you need consider (legally at least) for an approach ban on an ILS is RVR.
The Metar at the time of the accident had the
RVR for runway 17 as 350 meters and 375 meters for runway 35