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.