Inconsistent trim response
For me the trim and landing system seems to work inconsistently:
Sometimes it is like a dream - wheels and flaps and it keeps stable then trim to the middle of the E and float down using only the throttle to control my touchdown point.
And then, perhaps half the time, it's a nightmare. Wheels and flaps at 250 and 180 - and then it bucks up chasing the E and losing all speed. When I control the buck up with pitch it works but then doesn't seem to trim up - almost like my button doesn't work. In these situations the E and the glide marker are totally unconnected - swerving past one another only as the airspeed changes. My throttle control is OK but not great: I get leading - moving the throttle early and giving the engines time to react.
I just can't make out what makes the difference - some landings are a dream and some are a nightmare and there seems to be no difference in the aircraft setup or my approach.
So I guess I have a few questions:
Why does it work sometimes, and sometimes not?
What causes that initial buck-up?
Why does the trim fail to respond on occasions?