If your shuttle is flying off the track or your fabric is being beaten tighter on one side, or you have a diagonal beat/fell line rather than horizontal see below.Possible CauseHow to Fix It1) Shuttle boxes are out of adjustment.a) Single Box Flyshuttle: Bridge the Shuttle Race and Shuttle Box with a ruler or other straight edge. They should be in perfect alignment. If one is lower than the other, loosen the Shuttle Box and reposition it. If you need help, go to the installation instructions in your manual.b) Double or Four Box Flyshuttle: In the same way, check the position of each of your shelves relative to the race. If you have a problem, make the necessary adjustment at the turnbuckle in the cable that attaches to the shift handle; bring the shelves up or down. You may need to loosen the brass screws (motion limiters) top and bottom of the box carriages in order to create enough room to make this adjustment. Be sure to retighten them once you've corrected the elevation problem.2) Your shuttle is hitting the end of the reed.Insert small shims in the grooves that hold the reed into the race and beater top so that the end of the reed is deflected backwards.3) Tensioner in your shuttle is not adjusted.The advantage of an end-feed shuttle is that it allows you to tension the feed of your yarn. Most shuttles of this design have adjustable tensioners. Be sure yours is set to match the characteristics of the yarn used. Also, the tensioner opening on the side of the flyshuttle should be facing the reed. This way if the yarn does snag it pulls the shuttle towards the reed and not off. We try to avoid actual flying shuttles.4) Bobbins not wound consistently.If it's soft on the end and the wraps collapse and pull into one another, you will have to wind it again. Use an AVL Bobbin-Winding Guide.If one side of your fabric is beaten more tightly than the other (even when you are holding the beater in the middle), or if you have a diagonal beat/fell line rather than horizontal, your beater may be out of alignment.To check, push your beater all the way back against the Beater Bumper Blocks, it should strike both sides at exactly the same time. If it doesn't, you'll need to rack the beater.