So if the RVR apparatus isn't certified for smoke, what prevents an ARO going out and counting the lights to assess the visibility? I'm told the METAR gave the visibility and, if so, how was that obtained?
Where I once worked that (counting the runway lights) was how the crew determined if they had the required visibility for takeoff in poor conditions at airports where there wasn't any RVR equipment. Determining if the required visibility existed or otherwise was the crew's responsibility and counting the visible lights and multiplying the number seen by the known spacing got you the answer.
Doesn't an assessment of the visibility fall within the role of an accredited met observer?