When my FSX heli is sitting on the tarmac, every now and then it will jump up in the air an inch or so for a split second, then come back down. I can reproduce the bug pretty consistantly when I'm using the hat switch to rotate around it in an external view, but sometimes it will just be sitting on the tarmac and do a Mexican jumping bean act for no apparent reason. Any ideas? I never noticed this before installing SP-1.-Mick

You might need to increase the size of your "null" zone on your controler. Since this occurs when you are touching the joystick, you might be causing it with small movements.

I've pretty much ruled out a controller problem. I don't see anything fishy going on in the game controller config utility under the Windows Control Panel. Also, I would think that any sudden surges in the throttle input wouldn't translate into an upward movement of the aircraft - it wouldn't have time to react. These little hiccups are only for a small fraction of a second.

In case anyone runs into this, I was able to greatly improve (but not completely eliminate) the bug by tweaking the static_cg_height value. I was seeing a slight jump in the wheels when switching in and out of slew mode, then when I tweaked that value to eliminate the shift it also improved the hiccup problem.