Originally Posted by de facto
Air rabbit,
I really have no idea what you are blablaing about.
I never wrote that one should use a different V1 than given from his perf data.
I never said that V1 was a decision speed as i know it is a speed at which the first action must have been made,a definition that was changed a few years back.
Your way of discussing is quite abnoxious and no wonder you get burnt here now and then...jeeezzz,but then dont come and moan back here people put you back into place...
I was referring to the post you had made …
Originally Posted by de facto
Quote:
My post was to question whether or not we were launching, yet again, on the theme that pilots should have the ability to select whatever V1 they wanted to use … some were saying that they regularly use a V1 speed that is a significantly less number than the computed V1, simply to ensure that if a problem occurred, they would have sufficient runway to stop.
I definitively do not agree with such reasonning.
It would just require a longer take off run if the engine failed at V1 to accelerate to Vr hence invalidating your climb segments.
Your lead-off statement was “I definitively do not agree with such reasoning.” And, as I said, “…I’m not sure if you agree with me or with those who advocate selecting an arbitrary V1 speed…” – I wasn’t able to determine the “reasoning” with which you were definitively not in agreement.
But, notwithstanding that question, you also said “It would just require a longer take off run if the engine failed at V1 to accelerate to Vr, hence invalidating your climb segments...” and by “IT” I was, and remain, under the impression you were describing the selection of a V1 that was less than the V1 speed described in the regulations (- and, with some hesitancy, I understand that there may be some newly developed and distributed software that yields a “range” of V1 speeds, although I’m not at all sure how the various parameters are addressed in such a V1-speed range -). If you were not making such an acknowledgement – I did, indeed, misunderstand your comment – and I’ll offer you my apologies for my misunderstanding.
However, if you
were making that acknowledgement, as you would certainly know, as you have stated, V1 is NOT a decision speed – so if an engine failure were to occur AT V1, regardless of what the V1 value was determined to be, the procedures should remain consistent, and I would presume that would require that the takeoff would be continued. I am presuming (again) that if the V1 selected was within a range of “acceptable” V1 speeds, selection of any of those speeds should provide the same safety factors. If not, I cannot see why such an authorization would be granted. So, the fact that “…it would require a longer take off run if the engine failed at V1 to accelerate to Vr, hence invalidating your climb segments…” seems to be at odds with the premise that selection of any of the V1 speeds within an “acceptable range” of V1 speeds would provide the same safety factors. If, indeed, selection of a V1 speed that would “…invalidate your climb segments…” that selection doesn’t seem to be a viable alternative, I have trouble understanding why the operator would suggest and why the regulator would approve such a procedure. Under the “traditional” method of determining V1 speed, if the engine were to fail precisely at the computed V1 speed, with the decision to continue the takeoff having already been made, the climb segments determined should be able to be met. THAT is what the selection of that speed is designed to ensure, and the understanding is that any engine failure after the decision is made to continue, very well may not provide the same climb gradient as would have been achieved with all engines operating, but it acknowledges that, with such an engine failure, the gradient would be lessened with each knot closer to V1 that the engine actually failed – with the minimum climb gradient being able to be met with the engine failure occurring at the most non-favorable point along the takeoff run – AT V1. Again, THAT is what the selection of V1 speed is designed to ensure.
Now – with regard to your comment that my discussions are “quite abnoxious” … I guess the only thing I can say is that I regret you find my comments so personally difficult or irritating, and I would recommend that you simply not read them in the future. Also, I feel that I know what place I occupy – whether some here agree with my opinion or not – and I assure you, having someone not agreeing with me is not unfamiliar. I know that I attempt to comply with all the forum’s procedures and policies … as John T regularly says … “play the ball, not the opponent” and that is what I attempt to do.