LVTO with inoperative RVR measument units

[C.M]

If you are doing a CAT 2/3 approach the legislation ( by provision of the table titled “Failed or Downgraded Equipment - Effect on landing minimum operations ” allows you to use a runway with RVR measurement units that have failed.
However in the case of an Low visibility take off ( especially one under 150m) I have yet to spot such provision . The only LVTO statements that we have to work with are :
1. “The reported RVR/VIS value representative of the initial part of the take-off run can be replaced by pilot assessment.”
2. The required RVR value is achieved for all of the relevant RVR reporting points;

So from what I can infer if the initial RVR Unit is inoperative , the crew could entered the runway and make their own assessment. However if their take off performance was such that their ASDR was using the 2nd or the 3rd part of the runway , if any of those RVR measument units where to fail they would not be allowed to depart .

Please elaborate if there is provision for something different.

[chevvron]

I think I read somewhere you can depart if you can see a certain number of runway edge lights where they are standard 60m spacing.

[C.M]

The query of the post is different. It’s about unsevicabilities of the 2nd and 3rd RVR reporting point .The fact you can depart with crew assessment for the first part is already mentioned in the orginal post

[Chesty Morgan]

Chevvron that is just the requirement for runway edge lighting. We need a 90m visual segment which is 6 centreline lights.

The relevant RVR is what is important here and in the case of a rejected take off the mid point and stop end are the relevant ones. However, I reckon you could argue that, on a 4000m runway for instance, the stop end probably isn't relevant if you can accelerate to V1 and then slow to taxy speed by the end third of the runway.

[RAT 5]

From memory, which is becoming more suspect by the year, indeed the stop end could be ignored, either u/s or below limits, on very long runways. The start end RVR can be assessed by PIREPS, counting the centreline lights. Some operators might use edge lights, giving a slight diagonal distance and building in a buffer, but the centreline lights must still be working if <400m. That means mid-point must be working. The pilot can not assess that.