Ok, answer me this; I have the American Airlines B777-223ER downloaded from here, (Ithink).....

I'm sitting at the gate after choosing an airport, but I'm cattywumpus to the gate, so I turn on the slew to back up a little, and straighten out. when I turn off slew, I'm instantly moving forward at 275kts and accelerating! Not good when its into a building! What is causing this crap!?