In T124840#1623657, @oukej wrote:

External camera behavior in helicopters has been changed back to a fixed chase point so it's motion is no longer smoothed and it no longer moves vertically to retain vehicle's aim in the center.
https://forums.bistudio.com/forums/topic/204694-helicopter-camera/?do=findComment&comment=3203840

The hotfix helps but the 3rd person helicopter flying experience is still vastly inferior to the way it was in 1.68. It seems that the movement of the horizon with changes in pitch was dampened rather than eliminated.

+1 Pretty much everyone on Olympus is upset about the new 3rd person heli camera and wants it to be reverted to the old one.