Originally Posted by
BushrangerRed
Somatographic illusion is rare in helo ops, but not unheard of. Particularly on high wind low visibility transitions to forward flight off offshore helidecks. The ‘feel’ of achieving Vtoss rapidly after departing the hover, sometimes with poor horizon but excellent lateral visual cues, coupled with the attitude pitch up from accelerative to speed stable attitude (on the S92 sometimes 15-20 deg pitch up) does catch one out from time to time. Not to say somaatogyral issues aren’t also
at play.
I don't want to be argumentative, and I'm not an aviation physiologist, but I'm pretty sure that what you are describing is not SGI. SGI requires a sustained acceleration in the longitudinal axis, which combines with the Normal (as in at 90 degrees - not 'the usual') gravitational force, to produce a resultant force.This resultant force acting on the vestibular system creates the sensation of pitching up, or down. By definition, if you are taking off into a strong wind and accelerating to Vtoss, you are not experiencing a sustained acceleration, simply pitch changes, which I agree can lead to spatial disorientation but not from SGI.
If an aviation medicine expert wants to correct me, I'm happy to be so