Folks,
For US built aircraft, if one were to look up the various editions of the FAA Flight Test Guides, going right back to SFAR 422B, through the latest amendment to FAR 25, one would find that the major change is how the actual takeoff charts have been constructed, with differing “pads” in different eras.
The one thing that has NOT changed, ( but has never been taught very well to airline pilots) is the actual definition of V1.
It has always been:
“ The speed at which the takeoff must be continued, if the abort has not already been commneced”.
It follows that the failure, whatever it is ( not engine failure speed – don’t confuse this with certification requirements for engine out cases) has to be recognized, and a decision made, and the abort commenced, all before V1.
After some nastiness, some years ago, Delta did a survey of pilots turning up for recurrent training, by far the large majority described V1 as the “engine failure speed”, or “takeoff decision speed “, just as well we have not had too many critical aborts over the years, when the same survey was done in Australia, the results were the same as Delta, more or less.
Result, more educational material, changes to all Boeing manuals, articles in Boeing magazine, and a subject for recurrent training.
Now for another subject of much "debate", again FAA and SFAR 422B through FAR 25, who thinks Vref is 1.3 Vs.
Tootle pip!!