Mutt,
I suppose I haven't explained myself that clearly.
Your aforementioned 777 skipper...I concur. I'd always seek to use the TO configuration that kept the V-speeds to a minimum depending on the TOW for exactly the reason he suggests.
However,
whatever type of TO I am accomplishing, I'd like to know the
max V1 at which an abort is possible bearing in mind the
actual ASDA.
Presumably your skipper above isn't aware of whether or not it is the AGD or ASD that is limiting the BFL to a particular value, whereupon once V1 arrives, his decision is determined for him.
But isn't forcing me to go flying at a V1 determined from a balanced field analysis where it isn't the ASDA that is limiting imposing an artificial constraint on me unnecessarily? And with potentially the worst of consequences...
Sure, we have loads of margin in the case of an abort, but we've forced the decision to commit to getting airborne before we needed to.
Returning to my scenario above concerning PRG where we are considering a normal TO with V1=135kts and where an increased V2 speed TO for the same TOW gives V1=165kts, as
BizJetJock says, if I have a catastrophic failure at 135kts, from a performance point of view, theoretically getting airborne doesn't present me with a problem, but why take the risk in this scenario?
In this instance, I
know that I could quite safely abort from anything up to 165kts.
Some airlines do actually give crews min/bal/max V-speeds and allow them to make their own decisions
I think this sensible. I would still always use the lowest speeds which allowed me to get airborne for the TOW on the day, but am I missing something when I suggest that if a particular TO is possible at a particular TOW via a range of V-speeds, technically the option to abort always exists up to the max V1 possible?
