Need help . . . I have FSX Acceleration and can not get FDC to come alive.  There is a issue from when I start the 727 to take-off that the FDC turns off or does not want to turn "Autopilot Mode Selector".  Prior to taxing, I can get the AMS to turn, but once lined up with the run-way, it turns off and I can not get it back on.  I have tried assigning "Aviation master switch", but no luck