Bell 412HP Yaw Instability
Dear all,
There is an issue I've been having with a Bell 412HP on its yaw axis. During take off or approach for landing, there is a sudden left yaw that needs compensation from the pilots somewhere around the 60-65 knots area and whenever a power change is applied on either maneuver. I've already made several attempts interchanging Helipilots, CMTs and Tarsyn's but the issue still goes on. It is not the usual yaw reaction expected from a power setting change but a more inexpected and sudden motion of the helicopter.
Any thoughts?