Now I am confused. Lots of replies here that meant I had to go and look at the books.
So the OP asked...
When reported RVR is OK/OK/too low for LVTO, is it permissible to do a TO PERF calculation for the distance equivalent to the first two thirds of the runway, and go?
Well, what does YOUR Ops manual say? Could tell you what mine says but its no use to you. Perhaps even the info posted above may mislead you as most of it is AMC or EU-OPS and MAY not apply to your takeoff scenario. Not all AOC holders are equal. There are common obligations on them however, for example:
CAT.OP.MPA.100(a)
The operator shall establish aerodrome operating minima for each departure....
So to begin with its their risk assessment and they may expect all of the runway to be considered, even if on some days you can get airborne form the first 33% on a long runway. If a runway is shortened by notam then the operator is aware, but if crews are shortening it artificially?
Unless your operator is approved under SPA-LVO, the only ALLEVIATION for a REPORTED RVR is pilot assessment of the initial take-off run(AMC1.CAT.OP.MPA.100 Table 1.a or, if no performance, 2.a)
If you are LVO approved, then only the RELEVANT, reported RVR is limiting if this is defined in your OPS manual and varies by equipment and facilities(AMC1.SPA.LVO.100)
So it may be legal to depart in your scenario if the operator states so. RELEVANT is not a pilot determination, its an operators.
For me, I would consider the likelihood of zipping into the rollout portion with < 125m rvr and a burst tyre from an RTO a factor. So would my chief pilot probably.
Made me think though, good question.
Ps: here it is...
https://www.easa.europa.eu/document-library/technical-publications/easy-access-rules-air-operations"]
https://www.easa.europa.eu/document-...air-operations[/URL]