Hi, Sorry for all the posts (I have read the SDKs several times, if you're wondering)! I've exported part of my model to FS, using the default 737 as a base, and modified the contact points as appropriate. The model falls over backwards and crashes, but seems to be have itself OK in flight. Is this the result of using the default 737 .AIR file? Should I delete it? Here is a visual of the contact points using lights. These appear to be OK, and only just below the bottom of the wheels, named c_tire_still, l_tire_still and r_tire_still.