Great plane but major problem here - help please. After about 2 minutes in the air the fuel tank selector switches to the off position and refuses to be switched either to Front or Back. Of corse crash is end result. Happens every time. If I change to another plane all is OK. Goig back to the Falco, the engine is off and will not allow e to start because of fuel tank problem. I am forced to quit X-Plane and restart and the same thing happens. I did install as directed and the pliugin. MACOS 10.6 X-Plane 9.45 ???