Doing the tutorial, and got the engine, fmc, parts okay, read the manuals. After I take flight and set AP engage, it keeps popping out? Help me please. :D

If it's the J41 you're talking about then I don't think it will calculate the curved path needed to turn to your departure heading. I've noticed that I have to be turned onto a course which will give the AP a chance to intercept the magenta line. For example, if I'm flying a runway heading which is perpendicular to the magenta line then I've found that the NAV AP function won't capture the departure heading until I've turned roughly in that direction.

Thanks for the reply Mike, I've traced the problem just now down to a faulty trim pot on my x52 I do believe. Will do a little maintenance and see if it cleans up.