Originally Posted by bjornhall
... which is your gust load margin. If you use up that for maneuvering and hit even a minor gust...
Ok, perhaps I wasn't properly clear.
The aircraft has posted limits - If it's certified to 4g, you fly no more than that *including* allowances for gusts. I.e. if it's bumpy you do not manouver at 4g. Anything over that is an overstress, and is treated as such.
Same goes for Vne. They're hard limits.
I don't know the logic behind the certification requirements, I may be able to make guesses, but I won't - I'm certain however that it's not to allow you a gust margin. Bear in mind that the aeroplane can be irrevocably bent and still pass the test. (oh, and I'm wrong, it's 3 seconds, not 30.
The scenario was that if you're in a whole heap of trouble, heading down fast (assume you're going to break something, and it's no longer possible to stay within the envelope), what is most appropriate?
I think the answer is probably that it depends on the aircraft - seems some aircraft are more artificially limited by things like local mach effects etc (e.g. mad_jock's ride), however others (particularly lower speed aircraft) are going to be limited by high speed aerodynamic effects like flutter. G induces drag, which is a good way of slowing things down. I'm not suggesting that any load is applied abruptly, or carelessly - as we all know, the faster you're going, the more capacity you have to overload the thing.