The problem happens because you are using an airplane which is not already supported by GSX internally, and in addition to that, that airplane front gear position has been set wrong in the airplane.cfg, which is the information GSX will use, lacking any better information.
So, you should customize that airplane in GSX, as explained in the GSX manual, by setting all doors and the other important reference points, so the airplane will work correctly, even if some of its values in the aircraft.cfg file are wrong, because the customization you make in GSX will take precedence over any other data.
