But as far as i know, if you do not set the number of PAX via the LVar, GSX calculates the number of PAX internaly or not?
Only if the "Estimate passenger number" option is enabled.
The reason is, that prosim737
So, you mean you want to control the passenger number when NOT using your app ? Wouldn't be even better if Prosim could just send its own passenger number to GSX, same as GSX
What weight is GSX using if i do not set the number of PAX via the LVar ?
220 lbs, as explained in Pages 11 and 15 of the GSX manual, which is an industry standard of what a passenger + luggage usually weights. Since FSX/P3D aircraft modeling doesn't make any distinction between "pax" and "cargo" loading stations and it's not possible to know their kind, the most sensible approximation is using 220 lbs, which includes the passenger own luggage, as a rough average.
That's why, a product that doesn't take into account this issue, and might instead work with the weight of a passenger without his luggage, might not fit this logic, which in GSX could only work automatically by reading the overall weight of all loading station and dividing it by the number of passengers to do its ESTIMATE.
And that's why, the estimate itself can be disabled, and the actual pax number can be specified, either manually, or from the LVar. And if either of these options are used, the 220 lbs estimate won't matter anymore.