It is a well documented problem with the x-400. The elevator arm is sloppy and needs a drop of ca glue (recommended by ark) to make a solid connection. if you hold the elevator arm and move the swash with your other hand for and aft you should be able to locate the sloppy connection. You will need to remove the screw that holds the two pieces together to see the problem. A better fix is to buy the 120 degree CCPM kit as that removes the elevator arm altogether.