Confused or what, now:
So what is the correct answer:
turbine power is directly affected by densite alt, or pressure alt?
I thought it was always DA???
Vfr - howdy. You weren't demonstrated VRS, you were demonstrated IVRS.
Jack Carson: I agree with you it was demonstrated years ago. Sycamore pilots used to demonstrate it to ab initio RAF pilots in the 60's. I worked with one of these instructors for a while who explained that it was demonstrated only the once to each student during their course, from FL100. And very often, it took in excess of 7 thousand feet to recover. Some didnt make it. It was only when they looked into it in detail that they realised how silly it was practising it!
In fully developed VRS [which in theory most helo pilots should be aware of], you actually have NO control over the aircraft. If it decides to tip inverted, or stay fully developed all the way to the deck, then you've bought the farm! If you recover from fully developed VRS then it is not thru anything you have done..the a/c simply decides it wants to fall out of that state.
It's not to say a pilot couldn't demonstrate it...but he would be suicidal to allow it to develop fully.
juddering / wishy washy feedback from the controls / increase in ROD to excessive limits....is IVRS.
Loosing feedback from the controls completely, massive ROD's, excessive yawing and pitching...is VRS.