What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

OBS mode with G3X

lr172

Well Known Member
Hoping someone can help me sort this out. I am trying to figure out how to use the OBS mode in my G3X - 430W setup. Lets say ATC asked me to go to a waypoint (I am using GPS for guidance) on a specific bearing/course. With the 430, I use the direct function to enter that waypoint, but I need to dial in the specific course to that waypoint to follow.

I press the OBS button and the 430 makes me enter the course. I do that and the pointer on the PFD moves accordingly. However, the G3X also lets me press an OBS course button and twist the knob to change the course. This is easier to work with, however, I can't seem to figure out how these two different settings are interacting and which is being followed. Is the G3X overriding the 430 course that I had to enter?

Has anyone figured this out?

Larry
 
That's a good question, personally I never tried it on the G3X; I've just used the OBS setting on the GTN 650xi since that is the navigation "source" for the autopilot (in my setup..)

Will have to try this and see which one "wins" or do they end up syncing with each other...

*edit*

Did you read the Pilot's guide? See pages 78 and 345 (190-01754-00 revision M)
 
Last edited:
I press the OBS button and the 430 makes me enter the course. I do that and the pointer on the PFD moves accordingly.

Larry

I’m not a G3x expert. But, normally, when you push OBS on the 430, the box looks for course information from an OBS. If it cannot find it, only then does it ask you to manually enter it into the 430. So your issue may be an internal software setting in the 430 (my guess); or perhaps your g3x is not sending that data to the 430 (I think it requires an arinc connection out from g3, in to 430.)
 
I’m not a G3x expert. But, normally, when you push OBS on the 430, the box looks for course information from an OBS. If it cannot find it, only then does it ask you to manually enter it into the 430. So your issue may be an internal software setting in the 430 (my guess); or perhaps your g3x is not sending that data to the 430 (I think it requires an arinc connection out from g3, in to 430.)

That would make sense. On the other plane with GRT, the 430 doesn't ask for course. It just goes into OBS mode and the OBS can be adjusted via the heading knob. I have gone round and round with G3Xpert on this, as I guessed it was a config issue, but not a lot of answers. The last answer took three weeks to get, so I kind of gave up. Used to be good support, but since Covid there are long delays on responses.

I will play around a bit more and see if I can find someting in the config that may address this. The OBS CRS button won't appear in the G3X until I put the 430 in OBS mode, so maybe its a chicken and egg thing. I am hoping that once in OBS mode, the G3X changes will override what is in the 430. Just not enough testing in the air yet to figure it out.

Hopefully G3Xpert will chime into this thread.

Larry
 
Last edited:
That's a good question, personally I never tried it on the G3X; I've just used the OBS setting on the GTN 650xi since that is the navigation "source" for the autopilot (in my setup..)

Will have to try this and see which one "wins" or do they end up syncing with each other...

*edit*

Did you read the Pilot's guide? See pages 78 and 345 (190-01754-00 revision M)

Yes and I have seen this:

Enabling/disabling OBS Mode (with external GPS navigator
configured):
1) Press the OBS Key on the external navigator. The ‘Set OBS and Hold’ Active Flight Plan Page menu option is now available.
2) Use the OBS CRS Softkey on the G3X to select the desired course to/from
the waypoint.

However, when I press OBS on the 430, I am obligated to enter a course there. I just haven't done enough testing to see which course I am following. The 430 and the G3X will have different courses set and I have no idea which one my PFD is trying to follow. I understand that with enough in air testing I should be able to figure that out, but still concerned where there may be circumstances that will impact which is used. Don't want to be in the soup one day dealing with this.

I suppose I could just use the 430 course setting to deal with this and maybe that is the best approach, as I ahve confirmed that if I enter a course there, the PFD will use that to get me there on that course. I just miss the GRT, where it acts like a VOR and the needle swings as I turn the knob. More utility in that approach.

Larry
 
Last edited:
However, when I press OBS on the 430, I am obligated to enter a course there. I just haven't done enough testing to see which course I am following. The 430 and the G3X will have different courses set and I have no idea which one my PFD is trying to follow. I understand that with enough in air testing I should be able to figure that out,...

Larry

To answer this question:
Boot up avionics (on the ground) while holding the 430 ‘enter’ button in. The 430 will boot up showing the internal settings. Page thru them until you see ‘Main Inputs 2’. One of the boxes is labeled GPS SC which is gps select course. Put the G3x into OBS mode. Is the G3x OBS setting shown in the box? If yes then the gps should follow that data in OBS mode. If no, there is a communication problem.
 
To answer this question:
Boot up avionics (on the ground) while holding the 430 ‘enter’ button in. The 430 will boot up showing the internal settings. Page thru them until you see ‘Main Inputs 2’. One of the boxes is labeled GPS SC which is gps select course. Put the G3x into OBS mode. Is the G3x OBS setting shown in the box? If yes then the gps should follow that data in OBS mode. If no, there is a communication problem.

Thanks Bob. Will try that today.

Larry
 
Well, I got it working today. The manual is clear to set ignore SEL CRS for VLOC, but says nothing about the SEL CRS for GPS option. I changed that to allow and all works as expected now. Press OBS on the 430 and it no longer asks for a course. Instead I can now spin the knob on the g3x after pressing the OBS CRS button and see the needle spin just like I thought it should work.

Thanks for the help on this.

Larry
 
Last edited:
Back
Top