I was recently asked if I knew what VIBAL meant, found on some French Jepp plates. As I didn't know I thought it a good idea to find out. I did search PPRune but only found a reference to it a few years ago without a definitive answer.
Here's what I found out: RVR readings are taken using a transmissometer (machine), and VIBAL (visibilité balise) is a RVR/visibility reading taken by a person.
As too how Pilots can use it legally is another thing. Any ideas?
