CMV on Approach plates

[picollo]

Hi all,
EU ops have now started putting CMV on non precision approaches.
would anyone out there know the advantage of putting this on the charts?

thanks

[alatriste]

Hi Piccolo,
CMV stands for Converted Meteorological Visibility.
According EU-OPS AOM is " A value (equivalent to an RVR) which is derived from the reported meteo visibility by using particuraly conversion factors"
It is the minima for NPA when the required RVR is greater then 2000m.

The conversion factors are equal to those used to convert reported vis to RVR when RVR data is not provided by the tower.

You can find the table in the page 602 of the Jeppesen text booklet vol1.

Example: TWR reports 1100 m visbility and you need a CMV of at least 2100m to fly a VOR aproach. If you are at night time and HIALS and HIRL are operative for the active RWY, the conversion factor is 2, therefore 1100m vis equals to 2200 m CMV. Above minima.

[picollo]

Thanks for the reply. I think I understand it better now.

So instead of posting two values , one for RVR and one for VIZ, not they do the conversion for you and post it as CMV?

[bfisk]

For all practical purposes, CMV = RVR. The difference is that RVR is reported, CMV is calculated based on reported met.vis. (vis x 1,5 or 2,0 depending).

[3greens 1inthemirror]

what is the multiplying factor(x 1.5, x 2) dependent upon?

[underfire]

Conversion factors are per Appendix E of 9635

Illustrated as Appendix A of this document:

http://www.icao.int/safety/meteorology/amofsg/AMOFSG%20Meeting%20Material/AMOFSG.10.SN.011.5.en.pdf

[kuobin]

I also want to know"would anyone out there know the advantage of putting this on the charts?"

[jet commander 64]

Because if you get a general visibility (VIS) you can easily convert it in CMV and properly fly the NPA with CDFA technique, that is mandatory in EASA; most non LVP rwy in Europe and around the world do not have RVR trasmisometer.

[Lantirn]

Any news about this ICAO meeting that happened in 2013? (link by underfire)

Do we still use the same conversion factors?