The Long and Short of the Discussion - in my view
As much as I hate to sound like a broken record … it surely sounds like there are more than just a few who fly airplanes and are VERY FORTUNATE folks to still be here. The point that I think keeps escaping most is that there was a specific reason for having developed the “V-speeds” that are contained in the US regulations – and similar requirements in other nations. I am fully aware of how the numbers work and what they mean – and that humans using those numbers are likely to make some, even if only minor, mistakes … but that doesn’t alter the fact that sometimes it’s only a matter of small, sometimes very small, differences that wind up being THE difference between life and death – or at least accident or no accident. That is the biggest reason I’ve been on my “rant” of examining a lot of the “short cut” procedures that I’ve seen cropping up in daily operations … I call them “cheat sheet” methods to assist in either getting through the training or through a check - that sometimes creep into line operations. MOST of the time, those “cheat sheet” issues are derived from what works in … and then is offered to others to apply to … simulator sessions. Unfortunately, IF those procedures are learned well (and they almost have to be to be used to get through training or checks), there is a good chance that they will find their way into line operations. Two things about that:
1. There is no one around who is a bigger supporter of the use of simulation than yours truly … with the caveat that I regularly offer … that being that I do expect that the simulator should be fully known by the person running the show in that simulator … i.e., either the instructor or the evaluator … and that is because a simulator is NOT an airplane – and the ONLY reason it looks and functions as much like the airplane as it does is because a lot of people have put a lot of effort into making it seem that way. As long as the use of the simulator is kept within the boundaries of what the limitations of the physicality of what that simulator can support … how the programmers have incorporated data generated from an in-flight airplane … how quickly (both independently and dependently) any input made to the simulated airplane (either from the simulated airplane’s controls, i.e., the flight controls, throttles, brakes, etc., or the Instructor’s Control Panel) can be computed, compared to the airplane data, a result generated, and provide an output in the form of a simulator aerodynamic response … the simulator will, indeed, accurately reflect just what the airplane would have done in those limited case applications. However, if you get just outside of those very limited parameters (and believe me, the boundaries of those parameters have been expanded by unbelievable amounts over the last 3 decades!!!) you get into a simulator response that could very easily not be anything like what the airplane would have done. In fact there is an on-going effort – as some of you are aware – titled the “International Committee for Aviation Training in Extended Envelopes” which was specifically chartered to examine what kinds of any additional data or additional data sources would be necessary or possible from which additional simulator programming data could be acquired and used to program simulators to more realistically simulate a given airplane make, model, series, outside of what had been considered the “normal” operating envelope of that particular simulator.
2. Instead of something being developed in a simulator for simulator training or checking purposes, there seems to be those who believe it appropriate, during line operations, to disregard the identified speed above which an abort-worthy event occurring must NOT result in the initiation of an RTO (a Rejected Take Off). Instead, these persons believe that the identified speed does not provide an adequate margin of safety to stop if the RTO is initiated precisely at that speed, and they have decided that they will “reduce” that speed to provide additional runway to enable a safe RTO, should it be required. Once this procedure is decided upon and word is passed between crew members, this procedure is eventually adopted in some simulator training sessions. To no one’s surprise, selection of such a speed that would provide adequate stopping capability in an airplane, also provides adequate stopping capability in the simulator. However, an observant instructor or evaluator can usually pick up on the adjusted “V1” call and question the practice. It doesn’t happen often … but it DOES happen. Then comes the confusion. Additionally, here, in an anonymous forum, there is more freedom to describe such an event without fear of any repercussions (other than verbal). But the fact remains – while such an arbitrary speed reduction does, in fact, provide a greater margin for a successful RTO if initiated at or prior to the “reduced V1 call-out,” in fact, it ALSO leaves an increasingly gaping hole for what might happen if such an abort-worthy failure occurs AFTER that same “reduced V1 call-out.” And that is even more true in the airplane than it could ever be in a simulator.
So … again … overall … I fully understand the motivation that exists for the kinds of things this thread has brought out … BUT … before anyone arbitrarily reduces the speed at which they will “call out” V-ONE, please consider the facts of what that decision may impose on you if another, equally possible failure were to occur – or that same failure were to occur at a slightly later time. The results could be a lot more disastrous … by any measure. If it is your company that has “mandated” your compliance with this “procedure,” I would strongly urge to to bring that question before some arbitration panel or group to discuss the merits and demerits of such a compromise in what the regulatory requirement was intended to provide. If the rule should be changed for one operator … it should be changed for all operators – regardless of what that change entails. If the rule should not be changed – it shouldn’t be allowed to be “adjusted” on an individual basis.
(and by the way -- thanks Bubbers44 - for your cogent input)