Jepp Chart RVR/Vis
Thanks for the reply Flyboyike.
I have re read JEPPS INTRODUCTION page 114 which states " RVR visibility values are chartered only when the value is not the same as the prevailing or meteorological visibility value. When a difference occurs, the respective RVR and prevailing or meteorological visibility values are prefixed with "RVR" and "VIS". When there is no difference, the minimum is shown only once and means either RVR (if RVR is reported for that runway) or visibility if measured otherwise".
This partially answers my question, but from the above paragraph, wouldn't the "prevailing or meteoroligical visibility" always be different to the RVR, as the visibility is the slant range, wheras RVR is measured horizontally along the runway?
For an example there are aerodromes in Asia, where all of the aerodromes below have 3 transmissometers (Touchdown, midpoint, and rollout) where aerodrome 1 has only RVR's given, aerodrome 2 has RVR & Vis, aerodrome 3has 1200m only, aerodrome 4 has RVR and Vis for one runway & a figure of 900 m for the reciprocal runway which is 3 degrees offset for the ILS.