It's a bug and it's happened to me once I think after ATC gave me a heading to fly from take off. I never use fsbuild I create plans from charts off Navigraph and punch it in manually. Before I take off I always direct to the closest waypoint I need to fly and engage AP after gear and flaps up. Guess that lessens the chance of the FMS stuffing up. Pete Walsh.

Hello David,I know why it does not fly the heading of your flight plan. You must first build a flight plan from a thrid party flight planner. The FSX flight plan CANNOT be read by the BAE JS41. Once you have build a Flight Plan from a third party flight planner you can then save it under the name you have given to that route. I have found it easy just save it under the city codes given to airports such as KSANKLAX as an example.Next you must open the BAE JS41 "GPS". Once your GPS is fully open then go to the "FPL" and load the plan you have just made ( you might have to sroll down the list saved plans on the GPS and select your flight. IMPORTANT; You must also go through the complete setup in the GPS and load the fuel and PAX, just follow the direction it will ask for in each setup point of the GPS. Now It will the be ready for you to use during your flight. BUT, there is one more step you MUST do for the plane to follow the route and that is to push the LNAV button on the front upper console. Once you push the LNAV then push the "FULL MAP" on the EFIS COMPASS MODE in order to bring up the viewable route on the lower screen. THEN your plane will follow the route without fail. Trust me I have worked this plane with many hours trying find the reason it never follow my routes. Now I only wish to help other. David, If you have any problems and need more help, please leave your mobile number in my email box and I will call you and we can walk through the setup together.Happy FlyingTom (capttlm)

Hi guys, I don't have any problems with J41 and LNAV mode. My trick is to load it via flight save files instead of using default Cessna and FSX menu. Actually I do it this way for all my addon aircraft. Saves a lot of time... ;)Regards,