Good on you, 212man! The PBA did help that case, its contribution was included in the comment I made. The stroke of that Pitch Bias Actuator was not quite enough to fully cancel out the effects of the descent on the horizontal tail. This whole tale is told in 29.175 (bad pun intended).
The problem is that these rules were written when a typical helo Vne was 100 knots, so a .7 to 1.1 Vne stick check went from 70 knots to 110 knots. When Vne is 155 knots, the check goes from 108 Knots to 139 knots to 171 knots. The much bigger speed change brings on a much bigger descent, so the "level flight" check trimmed at 139 knots yielded a 1500 fpm climb at 108 and a 1800 fpm dive at 171!
Last edited by NickLappos; 28th Jun 2017 at 15:23.