Hello, As part of the X-FMC team dev, I would suggest strongly to remove some internal features like VNAV and ATHR... You can still use the LNAV function since it's only playing with HDG knob but depends if HDG dataref is from X-Plane or custom). Using X-FMC with a plane is not PnP (Plug n Play), you need to input the correct data, work on the config file a bit before going further... Well if you have any issue, please ask the community if anyone is interested to help you... (go to our official website...) Cheers