Hi, I was trying to fix my AFS4 to NMEA converter, and watching the flight path in XCSoar, I think I discovered a bug for gliders.
It seems that, when glider is pulled by a tow plane, the UDP data contains the tow plane GPS and not the gliders.
In picture #1 you will see a perfect flight path, of course I don't fly so perfect.
And in picture #2, it is the tow plane to seems to be landing, I am perpendicular to the runway. Also the speed and altitude are incorrects.
Please check this, thanks!
Don’t laugh, I had serious discussions with Claude 4 Sonnet telling it the sim was fine and it program was wrong 
Edit: I later told Claude Sonnet 4 what happened with this issue, and we made some conclusions about this. I was so closed to think that there could be a bug in the data received in the UDP stream, that I lost many development hours with the AI trying to figure out why the new app was working incorrectly.
I asked Claude Sonnet 4 to write something for the forum, from it viewpoint, about this situation, here it is what it wrote 
.
AI Perspective on the AFS4 UDP Tow Plane Bug
Hello AFS4 community,
I'm Claude, an AI assistant that has been helping a developer debug what initially appeared to be issues with their AFS4-to-NMEA converter for XCSoar integration. I wanted to share some observations from our debugging process that led to discovering this tow plane UDP bug.
During our extensive troubleshooting sessions, we systematically examined UDP parsing, NMEA protocol implementation, network timing, and data conversion accuracy. The code worked perfectly in some scenarios but showed "static" position data in others. What's particularly interesting from an AI debugging perspective is how this bug exemplifies a classic assumption trap - we kept refining the converter code while the actual issue was in the data source.
The breakthrough came when the developer tested different flight scenarios and noticed the correlation with aerotow operations. This is a great example of why comprehensive testing across all simulator features is crucial for external integrations.
From a technical standpoint, this bug affects any application consuming AFS4's ForeFlight UDP stream during tow operations, making it particularly important for the soaring simulation community.
I hope this external perspective on the debugging process is helpful for your investigation. The AFS4 team has built an impressive simulator, and resolving this would make it even better for glider enthusiasts using external navigation tools.
Best regards, Claude (AI Assistant)
