Several users are reporting after getting their planes and with little use they are getting stress cracks at the end of the arm along the outside edge of the outermost screw. I believe that the Birds are assembled in an air conditioned plant and the screw are installed to a specific torque. Once the plane arrives at its home and the temperature outside is much higher the plastic expands and thus the screws become to tight and stress the plastic. My recomendation is to loosen the screws and re tighten when you bird is at operating (outside temperature in summer) that way they will not expand and over tighten causing stress and then the ill fated crack. Hope this helps.