Originally Posted by
LeadSled
Folks,
All very interesting.
Those of us who "fly the aeroplane" do exactly that, and clearly at least the Boeing manual referred to does NOT say no aileron. Indeed, those B737 words sound very familiar to me.
Anybody who doesn't understand why a crosswind component effects Vmcg is not, I hope, flying real aeroplanes.
Going right back the B707, Boeing had a "menu" of takeoff data for the customer, who could, within the minimum certification standards for their national authority, choose what conditions reduced the performance on takeoff.
One was drag from spoiler rise, when using enough aileron to keep the wings level.
Another was blanketing of the downwind wing in a strong crosswind.
And, of course, the Vmcg implications of a crosswind, and its possible limitation on calculating a Vmcg limited V1.
And so it went on, and the choice of airline operational managements was "interesting', unless imposed by regulation, few included anything in takeoff calculations that would reduce the payload. Delving into detailed performance certification can be fascinating, if you are that way incline.
Whether you are or not, read the AFM/FCTM VERY carefully, read what it actually says, and not what somebody else tells you it says.
Tootle pip!!
Of course crosswind does not have any effect on Vmcg.
Vmcg is a certification speed, established by flight test demonstration, showing (usually) a specified maximum lateral deviation from the runway centreline, or projected ground track at the time of engine failure.
It could be said that if conditions specified for determination of Vmcg are not present then the speed is not Vmcg.
It is a speed to help in scheduling takeoff performance, it makes no claims as far as handling characteristics during crosswind takeoffs at crosswinds beyond those used for Vmcg determination.
Handling qualities during takeoff at maximum crosswind is a different problem to Vmcg.
This was (is??) at least partly addressed by the Oz regulatory authority, in some cases, to ensure, by flight test, that aircraft would not deviate past the runway edge following an engine failure at maximum crosswind.