Thanks for the quick reply. FSX does not have any addons, default installation.
I will create the log and post it here.
I have tried different things. Start FSX as admin or not, in compatibility mode (Win7 and Vista), Fsuipc registered and not registered and an older version. All works in your example file, only Fuel read and write and set the radio frequency not. However, the radio frequencies are read out correctly.
FSX is FSX Gold with Servicepack 2.
********* FSUIPC4, Version 4.976 (15th January 2021) by Pete Dowson *********
Windows 10 Home 64 Bit reported as Build 19043, Release ID: 2009 (OS 6.1)
fsx.exe version = 10.0.61472.0
Reading options from "C:\FSXGold\Modules\FSUIPC4.ini"
Running inside FSX on Windows 7
Module base=55E20000
User Name=""
User Addr=""
FSUIPC4 not user registered
WIDEFS7 not user registered, or expired
16 System time = 03/12/2021 11:51:07
16 FLT path = "C:\Users\Löwenrudel\Documents\Flight Simulator X Files\"
16 ------ Module Version Check ------
16 acontain.dll: 10.0.61472.0
16 api.dll: 10.0.61472.0
16 controls.dll: 10.0.61472.0
16 fs-traffic.dll: 10.0.61472.0
32 G3D.dll: 10.0.61472.0
32 language.dll: 10.0.61472.0
32 sim1.dll: 10.0.61472.0
32 visualfx.dll: 10.0.61472.0
32 weather.dll: 10.0.61472.0
32 window.dll: 10.0.61472.0
32 ----------------------------------
563 Trying to connect to SimConnect 10.0.61259.0 ...
610 ... Okay! Connected!
672 FS path = "C:\FSXGold\"
1532 LogOptions=00000000 0000000D
1532 -------------------------------------------------------------------
1532 ------ Setting the hooks and direct calls into the simulator ------
1532 --- CONTROLS timer memory location obtained ok
1532 --- SIM1 Frictions access gained
1532 --- FS Controls Table located ok
1532 --- Installed Mouse Macro hooks ok.
1532 --- Wind smoothing fix is fully installed
1532 --- G3D.DLL fix attempt installed ok
1532 --- SimConnect intercept for texts and menus option is off
1532 --- All links checked okay
1532 -------------------------------------------------------------------
1532 SimConnect_Open succeeded: waiting to check version okay
1532 Opened separate AI Traffic client okay
3172 Running in "Microsoft Flight Simulator X", Version: 10.0.61472.0 (SimConnect: 10.0.61259.0)
3172 Initialising SimConnect data requests now
3172 FSUIPC Menu entry added
3219 C:\Users\Löwenrudel\Documents\Flight Simulator X Files\GearDuino.FLT
3219 C:\FSXGold\SimObjects\Airplanes\A320-214\CLEANcfm56_5B4.AIR
3813 User Aircraft ID 1 supplied, now being used
3813 Aircraft loaded: running normally now ...
54266 System time = 03/12/2021 11:52:01, Simulator time = 11:51:10 (10:51Z)
60766 Starting everything now ...
62094 Advanced Weather Interface Enabled
151844 Sim stopped: average frame rate for last 92 secs = 24.5 fps
151844 Max AI traffic was 17 aircraft (Deleted 0)
[Log closed by user request, and continued in new file]
170016 System time = 03/12/2021 11:53:57, Simulator time = 11:52:43 (10:52Z)
170016 *** FSUIPC log file being closed
Minimum frame rate was 20.4 fps, Maximum was 24.8 fps
Minimum available memory recorded was 3084Mb
Average frame rate for running time of 92 secs = 24.5 fps
G3D fix: Passes 7600, Null pointers 0, Bad pointers 0, Separate instances 0
Maximum AI traffic for session was 17 aircraft
Memory managed: 47 Allocs, 46 Freed
********* FSUIPC Log file closed ***********
FSUIPC4.1.log