we'll have to agree or disagree at some stage but in order to do so we need a very concrete practical example. Surely one of those wide bodies taking off from NRT to cross the pond is at RTOW for 10+ flight time. And I haven't seen many of them deferring takeoffs with low level wind shear advisory in effect and officially -+20 knots speed variation being on ATIS. Are you suggesting they're all gamblers? There's theory and practice. That's why I said it all depends on too many factors and rightfully the commander will make a call.
did I miss something ? I was sure that you were talking about min V2 schedules and not increasing speeds to take advantage of improved climb capabilities (regardless of OEM) at speeds modestly in excess of min V2.
I was talking bout optimized performance speeds and optimum V2/Vs + V1/VR ratios which inevitably leads to V2 being higher as VR. I'll clarify my previous post by saying that for a ATOW=RTOW one is bound to keep VR and V2 but can take a lower V1 or for ATOW<RTOW one can take V1 for ATOW and VR/V2 for RTOW but they always go together. I've never seen VR being higher than V2. That's the whole point of the discussion here.
VR + 20 makes sense if IAS provides reliable indication and isn't screwed up by WS. If the WS hits you at the range close to VR +20 then it's virtually impossible to identify VR+20 as the IAS is all over the place. That's also why I think airbus's concept of optimized speeds and energy management is more efficient. There are many ways to skin the cat that we all agree upon.
