Good afternoon,
I have P3Dv4.5 and I usually fly with a320 from aerosoft.
To prepare the flights, I use FSC9.
I currently have the AIRAC 2112 from NAV DATA PRO installed on FSC9, on A320 PROF. and in an external program that I use for traffic control.
From FSC9, I can see all airports and create routes. But when I use the airplane's Fuel Planner to calculate the fuel, some airports that do appear in the route created by FSC9 are not recognized by the Fuel Planner nor by the MCDU (when I try to load the route into the MCDU, there is data that I can't add for example the COST INDEX or the FL). It is as if some airports do not appear in the aircraft database, even though both programs contain the same AIRAC.
What could be happening?
Thank you very much in advance.
All the best

The reason is very simple: the navdatabases you can get for the sim from various providers (in case of NavdataPro it is Lufthansa) are real world data that fits to the needs of their airline customers and if none of them flys to a certain airport it is not included. So a navdatabase will never cover 100%.

The reason why you find the airport in FSC is, that FSC takes the airports directly from the sim, but only the aiport. For everything else (procedures etc) it needs an external database.