Multiple RVR Data
 

I'm prepping for an interview. As I prepare, I'm reading through the 10-9A for KCLT and have come across an interesting question. I've never actually seen multiple RVR's (based on position, not runway) reported in a METAR before, and searching for samples of multiple RVR METAR's has yielded little.

So, for runways 18L/R, and 36L/C/R:
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"2 operating RVR's are required
All operating RVR's are controlling."

CL & HIRL

TDZ RVR 5
Mid RVR 5
Rollout RVR 5

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For clarity: I've seen RVR reported for multiple runways (R18L/0500;R18R/0500), but how would I see dilineated positions?

Additionally, if all three positions are operating, I would assume that if one of the positions reported less than minimums I'd not be able to takeoff -- if that same unit were offline and not reporting this wouldn't matter -- correct?

The METAR is only going to give you touchdown RVR. The Federal Meteorological Handbook Number 1 (the observers guide) says the RVR sensor used for the METAR should be within 500 feet of the runway centerline and within 1000 feet of the runway threshold. They can report up to 4 different runways.

To takeoff in lower than standard TO minimums the airline must be approved for lower than standard TO minimums in their OpSpecs and the crew must have been trained to that lower minimum. You can only operate to higher of what your OpSpecs allow or what the chart says.

In your CLT example the chart says two transmissometers are required and all are controlling to takeoff at RVR 500. In addition the runway centerline lights and the high intensity runway lights must be operational. If either of the lighting systems is inop you are limited to RVR 1000 even though you may be approved for RVR 500 takeoffs. And you would still need 2 operating transmissometers and all are controlling.

Typically, the lower the vis, the more RVRs values are reported. They can be put into METAR format in ATIS and I haven't seen one particular standard. It can be as simple as "RVR 500/700/300" (with the first being TDZ, then MID and RO). When the weather is down to CAT-3 (or even CAT-2) minimums and 2-3 RVR values are required and being reported, they are usually being reported verbally by the Tower. The reports can be provided as often as every 10-15 seconds and rarely go longer than a minute without an update. This is due to the fact that reports below minimums on CAT-3 approaches even after established on final require a go-around prior to alert height. It's not realistic to expect a crew on an approach to be constantly checking ATIS for new RVR information that could be changing rapidly.

Correct on both statements.

Also, Runways longer than 8000’ usually have a 4th sensor, “Far End” RVR sensor.

Thanks so much for your help. This is exactly what I'm looking for!

Thank you for your help. I sincerely appreciate it!