ATC RVR readings without transmissometer
Question ATC lads,
At an airport where there is no transmissometer - Can the ATC legally give a RVR distance (as they normally just count the runway lights visible from the end of the runway for distance estimate). With shallow fog 100ft> this airport experiences low RVR's with high Viz.
I just experienced myself a few times whereby we are 10 miles from the field with the runway in sight with shallow fog - with tower reporting Viz of 800m yet the RVR of less than 350m. We needed a RVR of 550m to shoot the approach. It is strange to have Viz more than RVR as it should be the other way round. They would not let me attempt an approach due to the RVR distance reported, despite if I converted the Viz to RVR than I would be legal.
I am just trying to clarify if the airport can "count the lights" for an accurate RVR reading, or if their Viz estimate is their only legal reading, whereby the pilot can convert the Viz to RVR with the appropriate table. I was under the impression that only pilots did the "counting the lights" for an estimate for take off only. I have searched the publications to no avail...any help?