It's a popular misconception that LVPs are only associated with Cat II/III. At Luton we didn't have LVP as such until we introduced Cat II/III (Oct 92) but once we wrote the procedures we always went into LVP before we got near Cat II/II limits. Now we have to be in LVP and the runway safeguarded by the time the IRVR has reached 800m, in practice we start this at 1500m or more, depending how quickly the vis is dropping. Or the cloud has reached 200ft. . . .
As afterthelanding says, you may need to be in LVP because the cloud has lowered to 200ft or below, yet the vis is still good below it. This is why at Luton we introduced a half-way house we know as Vis 2. We use the Cat II/III holds but all the taxiway cl lights are on up to those holds. We only start full twy routeing when the vis drops to 400m or less (what we call Vis 3.) [Vis 2/3 does not equate with Cat II/III.]
I haven't got an Annex 14 at home but I'll try and dig one out at work and see what it says.
[ 15 January 2002: Message edited by: Lew Ton ]</p>