I have write the message upon to help you not to criticize....... I love this pgm and your job is very appreciated by myself....
Sorry for misunderstanding....

In XP11 we have 3 (Three) nav_data files...... the first one is in the old place \Resource\default data\ and this is the original the second may be in \Custom Data\ customizable by the user and it's used if the directory is not empty and if earth_awy.dat and earth_fix.dat are present. The third Nav-Data file is located in \Custom Scenery\Global Airports This file is mixed with the other two nav_data files.......... In substance we have \Resource\nav+data + \Custom Scenery\Global Airports\nav-data  ........ or \Custom Data\nav_data+ \Custom Data\ nav_data if the dir Custom Data is not empty..... I believe that Plan-g has to read XP11 nav_data with the same rule....... Some test in XP10 says that if data are not in the correct order they are missed... and this is another little problem....

Here are very important infoes about the new structure of NavData in XP11

http://developer.x-plane.com/?article=navdata-in-x-plane-11

It seems that the real earth_nav.dat is now located in:

Custom Data\earth_nav.dat

................................

This version sounds good!!!  Tnks Tim!

Thanks a Lot Tim.....

When i try to generate the db with last release of Xp (10.40b2), it's freezes in the step "sto scrivendo 35380 piste" after apt.dat scan

Mi si congela PlanG in fase di generazione dati al momento in cui va a scrivere le piste......................