Hi, I use XP11 with "X-Plane 11 Global Airports Update" :https://forums.x-plane.org/index.php?/files/file/76515-x-plane-11-global-airports-update/

When I build XP11 scenery library, I noticed most Chinese airports have shown on map and flightplan as IATA code. but if I search or create flightplan with ICAO code, it also works.

However when save to flightplan, it will save as IATA code, confuse the FMC which try to load them. a workaround for me for now is select "Use Navigraph for all feature" before export, but it's kinda annoying...

When check the airport details,  there is no ICAO Code line as other airports, but IATA, Local Code and X-plane Ident, the later 2 are both ICAO code inside. a "Normal" airport have no "Local Code"

 

I know there might be some issue with this airport pack, I have comment there for a while but no reply, just wonder if I can get around it in LNM like select what code to use as default? Thanks.

LNM shows TSN before ZBTJ since it prefers IATA before local or X-Plane codes. If there were a ICAO code it would use this one.
It is a bit difficult to decide what airport code to use for display or save in FMS files. The X-Plane stock FMS and the GPS can also deal with IATA codes in FMS files.

I see here that TSN actually has an ICAO code ZBTJ assigned: https://en.wikipedia.org/wiki/Tianjin_Binhai_International_Airport

But it is not denoted as ICAO code in in the apt.dat:

1     13 0 0 ZBTJ TIANJIN Binhai International
1302 city Tianjin
1302 country China
1302 datum_lat 39.123333333
1302 datum_lon 117.345
1302 gui_label 3D
1302 iata_code TSN
1302 local_code ZBTJ
1302 region_code ZB
1302 state Tianjin Municipality
...

I'd post a report on the X-Plane Gateway or even better: Fix it right away with WED and upload a patch.

Alex