Is there any way to amend the airport data with those of missing airports extracted from FSX?
There are quite a lot of airports not included in Navigraph's data set (e.g. MMCB, MMIT, MM35, MM41 and almost all other MMxy from Mexico) and it seems to me that it is not sufficient just to extend the apts.txt file with data having the same format. I wrote a little tool extracting all airports of a given minimum runway length and selectable pavement for ISG1 which works fine but when copying just missing APT data over to the above mentioned FSBUILD file it does not work within this application even if the format looks the same.
FSBUILD does not react to any input unless I delete the changes and thus it seems that I have to do something more. Do I have to change the Fsb_city.txt accordingly? What else???
Assuming you are using the (at least) AIRAC 1204, the apts.txt file does include MMCB, and MMIT. Note that the file also includes runway data and that the airports must be added in alphabetical order by ICAO. So far as I know the Fsb_city.txt file is not used in version 2.4...