Thanks for these posts. I do have a problem though that seems to fall outside this advice and seems to happen each and every time I do a turnaround without ending the flight and reloading. If I land - go to gate - load up and take off I get this problem 100% of the time. Basically the AP won't engage after takeoff. The LNAV, VNAV, all other lights will light up but I can't engage either CMD button. Even with the FDs on, etc. It's just the CMD buttons won't light up and the AP won't engage. I have realistic AP off. I've tried loading cold and dark between flights to see if it resets the AP. I've tried just loading in the new route. No matter what I do on that second flight I can't engage the AP. I think I've tried every variation I can and can't figure this out. I've checked all the above requirements and made sure I don't have a failure or maintenance need. No luck. Anyone else have this or know how to fix it?
It makes it impossible to do a quick land, turnaround and take off. I have to either exit FSX or take off and load an old saved panel with a flight plan from a prior flight and then re-enter my new plan. Default states or Cold and Dark don't fix it.