Originally Posted by
zzuf
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.
zzuf,
I hope you are not actually a pilot, you clearly know very little about Vmcg certification, and what you do know is in error.
Could I gently suggest you do a bit of homework on the subject, even the different requirements either side of the Atlantic at different periods.
Your last line is particularly interesting, as Australia (thank goodness) has not had its own unique airworthiness requirements since 1998, where the last of the ratbag local impositions were buried in an unmarked grave, and as for Vmcg speeds, have been as per FAA since a long time ago --- as opposed to those who wanted to impose BCAR methods.
I can tell you from actual experience, in a B747-238, with only a 25 kt. X-wind, and a full de-rated takeoff, the "wrong" engine losing thrust at a Vmcg limited V1 resulted in demolishing some runway lights.
Tootle pip!!
PS: The details of how a particular type an variant is certified (FAA) will be found in the flight test guide that FAA and the manufacturer settle as part of the certification process. Tracking the history of certified approach Vref speeds is a good case in point, it has been a long, long time since Boeing used 1.3Vs as the basis for Vref.