Then, shall we keep the discussion going until we collectively achieve agreement or the alternative ?
Are you suggesting they're all gamblers?
An advertised 20kt shear is a tad different to a snarling tiger of a downburst .. ? One really ought to keep one's goalposts stationary.
rightfully the commander will make a call.
Of course.
I was talking bout optimized performance speeds
We were aware of that ... however, such uses an overspeed takeoff ie you have already increased your VR and V2 which, as a sideline benefit, keeps you further away from Vs.
ATOW=RTOW one is bound to keep VR and V2
That doesn't follow, necessarily. While it would be a risk dilemma in the case of a critical ASDR situation, other limitations may give you a bit of Commander's discretion.
I've never seen VR being higher than V2.
Semantics. If you adopt a VR higher than that scheduled, then the V2 achieved necessarily will increase in line .. regardless of what you might choose to set on the ASI bug.
VR + 20 makes sense if IAS provides reliable indication
Those of us from a different era are concerned less about (a fluctuating) ASI and more about N1s and ball angles. IAS indication is nice to have but not a necessary condition for continued safe flight.
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.
Some days things just aren't fair, I guess. However, apart from primitive presentations, we all have some sort of GS indication .. I, and most of my olde phart colleagues, routinely monitored that indication .. which then provides something akin to the get out of jail free card in your postulated scenario. Again, the wise Commander, for the great majority of occasions, will have made a sensible call according to the reasonable to infer likely outcome of the present weather .. prior to commencing the takeoff roll.
There are many ways to skin the cat that we all agree upon.
Absolutely the case, good sir.