Originally Posted by
KingAir1978
I'm not really sure what you're trying to say, Stanley.
EASA:
First of all it is possible to convert visibility to CMV/RVR, I don't think you can reverse it and convert a required RVR to visibility that should be present.
The conversion factor -in case of HI approach lights/runway lights- 1,5 day and 2.0 night.
The conversion cannot be used for:
- Take off
- For calculating a required RVR less than 800 m (i.e. 550 meters for a standard ILS)
- When RVR is available.
Secondly, when the VIS drops below 800 m YOU HAVE TO BE PROVIDED with RVR information.
Would this mean then that if you arrive at destination, (which, let`s assume, has a published minimum CAT1 RVR of 550 m), that if the met vis on the ATIS is 700 m, but the RVR system is inoperative, that you can`t make an approach - even though the `RVR` (if it was available) is HIGHLY LIKELY to be over 1000 m?
Or, what about a
single pilot CAT1, who with his `limited` available ac equipment/avionics, is forced to use a modified min EASA RVR of exactly 800 m. He would, surely, be legal because he now CAN use a CMV conversion: [700 met vis x 1.5 (day)] =
1050 m CMV!! = LEGAL!!
So, is the obvious solution for the A320 CAT1 two-pilot operation to knock out the co-pilot, fly a manual/raw approach, and become a `single pilot operation` ?
Just out of interest, I can`t see any reference to a min met visibility of 800 m for a CAT1 approach in EASA; I assume it is mentioned in ICAO?
EASA CAT1 Definition:
‘Category I (CAT I) approach operation’ means a precision instrument approach and landing using an instrument landing system (ILS), microwave landing system (MLS), GLS (ground-based augmented global navigation satellite system (GNSS/GBAS) landing system), precision approach radar (PAR) or GNSS using a satellite-based augmentation system (SBAS) with a decision height (DH) not lower than 200 ft and with a runway visual range (RVR) not less than 550 m for aeroplanes and 500 m for helicopters;