Hey I am about to purchase the PMDG 737 but I am confused about what this AirNav stuff is used for or what all of these downloads are for the FMC. I have never used a product with a fully functional FMC so this is all new to me, could someone plese help me with the understanding of AirNav and other downloads for this FMC. Thanks, Billy

If you mean the AIRAC NavData, it's a library of files containing all the world's waypoints and fixes used in aircraft navigation. They are necessary for programming our FMC database.Best,