That works fine on something like the Huey, but the Apache's autopilot/stability augmentation system
That works fine on something like the Huey, but the Apache's autopilot/stability augmentation system will be fighting you all the time. Sometimes you need to tell the autopilot "hey, this is the attitude and heading I want to be holding", and the only way to do that is with the trim button. The trim button is also the only way to reset the autopilot channels when they get saturated.
