Normally a visual approach is the completion of an instrument approach by visual means. So there cannot be a general minimum for visual approaches. It always depends on the Instrument Part which brought you there.
There are approaches, where the instrument part brings you to a fix/VOR/NDB positioned 2, 3 or even 5 NM out from the field. In order to continue, you have to have the RWY in sight.
Now you need at least 2, 3, or even 5 NM visibility for this perticular approach.
For an ILS this means: The "Instrument part" brings you into a position 200 ft above the RWY (decision alt), or ~ 0.6 NM from the Loc Antenna. 0.6 NM are actually roundabout 1100 m. So the 800 m RVR are the absolute minimum to complete this approach by visual means.
Especially for ILS Approaches check your company procedures for the following: What exactly means RWY in sight? Threshold lights? Approach lighting? And which part thereof? How many Lights?
Circling: The only reason for the 2400 m minimum during these kinds of approaches: it shall give you the chance to maintain visual contact with the RWY at all times during the manoever.
But if you look at those 2400 m and your lowest minimum of 600 ft, you'll soon find out, that this is practically impossible. So make it 3000 m for your own decision making, before you accept a circling approach.
Regards Charly
(I'm not sure, if your company has approved them, but if they did: check NCE VOR Approaches 22L/R and VOR 04L/R for nice examples: high minimum and a visual track to follow therafter)
Last edited by Charly; 17th April 2007 at 23:05.