Longitude Simbrief import with incorrect altitudes

Avionics Plugins
3

Ok, so I investigated this a bit further during the development of our G1000 plugin and after some discussions with the beta team, it seems that this is not as simple as it might look, for several reasons:

  • The altitudes you get from SimBrief, just like real life, are approximations based on the performance numbers for the selected aircraft. These numbers can vary from aircraft to aircraft, even if they are the same model. This is also a factor in simulators, as the simulator aircraft doesn’t necessarily fly according to the SimBrief numbers. The safest (and hopefully most correct) option is to let the FMS of the aircraft handle the altitude calculations.

  • The current WT avionics is missing the “Active performance” page that is used to set the cruise altitude in real life. This means that in order for us to set the cruise altitude, we would have to either:

    • Hack and override the internal calculator used for the vertical leg calculations
    • Add altitude restrictions to the enroute segment.

    Because of the reasons outlined in the first point, it is not possible to guarantee that the aircraft is able to make the restrictions. Restrictions are also meant to be set explicitly and manually by the user, not by an automatic import. It seems like WT currently is working around the lack of cruise altitude setting by using the altitude preselector, so that would be the “official” way to handle this at the moment!

  • If you import a PLN file with a set CruiseAlt (and the extra values in the WorldPosition) in the world map of MSFS today, you can see that the WT avionics do not handle it at the moment. They override the specified altitudes with calculated values, probably based on the altitude preselector somehow as mentioned above.

All in all, we have been advised against trying to implement this feature at the moment, at least until WT introduces the Active Performance page, if they decide to do so.

I will continue to monitor this to see if there are other ways to work around it, and will keep you updated!

Kind Regards,
Malte