As with most I’m loving the NZ update and took the opportunity to do a fresh install of MSFS. The only add-on I had installed was navigraph-navdata. So I was surprised to see an oddity on my ‘Home’ airport, in Cromwell - by the Big Fruit Removing the Navigraph Navdata fixed the issue. So I think this is a bit different to the usual double scenery elements issue as I have no add on scenery bayeond the MS world updates
So this is squarely a Microsoft problem for using the wrong airport code for Cromwell Airport, which Navigraph uses correctly. Microsoft uses NZWH - which is actually Wellington Hospital Helipad and Navigraph uses NZCW - Cromwell.
I know there is a thing where Navigraph can’t change the code of an MS airport but is there a way to adopt the Microsoft code where the distance between airports is less than X NM? Say 1? I’m guessing that this would cause an issue where there are dual codes at an airport like military/civilian airports.
I looked into it using data exported from Littlenavmap and the other ones I found in NZ using a very basic search on airports sorted by latitude: 0.002 > SQRT((Lat 1 - Lat 2)^2 + (Lon 1 - Lon 2)^2)
There are also a list of fictitious codes that will need to be watched to make sure that if CAA NZ uses those for new aerodromes that they don’t break other stuff.
Thank you very much for your detailed report/posting … Indeed, this is a general, worldwide issue in the MSFS. ASOBO uses old/outdated ICAO codes and/or fictive ICAO codes for some airports.
As you have identified, the airport ICAO codes are stored in different locations/files. There is a generic airport file, which can´t really be “overwritten/overruled” due to the internal logic in the MSFS - so we have no possibility to correct such information. Also, not with any fix in the priorities of the content-file because this generic airport-file will automatically be loaded by the sim.
What we don´t want is, that we “exclude” such double airports (due some distance calculation) from our database only because they are included in the MSFS stock data. You can´t “create” an airport without any runways - so only to create the airport ICAO code for the airport doesn´t work.
Sorry Jamie, we have spend a lot of time to find a solution for this but till now, we haven´t found any - to compare the default MSFS scenery data with our real-world data is very difficult and error prone as we have seen in the last WU, where ASOBO has changed/corrected/deleted some ICAO codes.
Sorry but again Jamie, thanks for your constructive posting and sharing your ideas to this topic. Possibly we shall find a way in the future - never say never
… the next SU is planned for August, at the earliest … but I´m “pretty” sure that they will fix it in one of the next WU
Thanks Jamie for your valuable input and your help in this case … we are also looking for any improvements of the MSFS, possible we will also find a solution to fix, we will see
Greetings from Austria to the other side of the world
Richard
Removing the Navigraph Navdata fixed the issue. So I think this is a bit different to the usual double scenery elements issue as I have no add on scenery bayeond the MS world updates
… the next SU is planned for August, at the earliest 
