G3X -> G5 autopilot failover mode

[rbp]

here's the squawk I reported: "with G3X PFD breaker pulled, there is no FD/AP/YD/elevator trim control, either on G5 or on GMC507 [GFC500 controller]"

I expected that if the G3X failed, I would be able to just look at the G5 AI and use the panel-mounted AP controller.

but here's what the avionics tech wrote me today, after looking at my squawk: "G5 and MFD work fine when PFD breaker is pulled, you have to re initialize the autopilot to come back up, it does not switch automatically. I had to reset the A/P breaker sometimes to get it to pass the PFT. I tried about a dozen times. We can go over it when you get here."

it seems wrong to have to recycle the AP to come back on line.

[Ragsf15e]

18 minutes ago, rbp said:

here's the squawk I reported: "with G3X PFD breaker pulled, there is no FD/AP/YD/elevator trim control, either on G5 or on GMC507 [GFC500 controller]"

I expected that if the G3X failed, I would be able to just look at the G5 AI and use the panel-mounted AP controller.

but here's what the avionics tech wrote me today, after looking at my squawk: "G5 and MFD work fine when PFD breaker is pulled, you have to re initialize the autopilot to come back up, it does not switch automatically. I had to reset the A/P breaker sometimes to get it to pass the PFT. I tried about a dozen times. We can go over it when you get here."

it seems wrong to have to recycle the AP to come back on line.

Calling @PT20J…

Skip has better insight on how this thing works or is supposed to work than eveN Garmin and he has the same g3x, g5, gfc500 setup.

[PT20J]

44 minutes ago, rbp said:

here's the squawk I reported: "with G3X PFD breaker pulled, there is no FD/AP/YD/elevator trim control, either on G5 or on GMC507 [GFC500 controller]"

I expected that if the G3X failed, I would be able to just look at the G5 AI and use the panel-mounted AP controller.

but here's what the avionics tech wrote me today, after looking at my squawk: "G5 and MFD work fine when PFD breaker is pulled, you have to re initialize the autopilot to come back up, it does not switch automatically. I had to reset the A/P breaker sometimes to get it to pass the PFT. I tried about a dozen times. We can go over it when you get here."

it seems wrong to have to recycle the AP to come back on line.

The GFC 500 has software in multiple components. The G3X and G5 contain part of the logic, and the servos contain part of the logic. The mode controller is primarily a user interface. So, when you pull the G3X breaker, it shuts down the autopilot because that part of the logic is now gone. You can manually restart the autopilot and it will now use the G5 logic in place of the G3X. You shouldn’t have to do anything with the AP circuit breaker. I don’t recall if the G5 PFT runs after a G3X power down, but if it does you will have to wait for it to complete before the FD or AP will work.

Skip

[rbp]

7 minutes ago, PT20J said:

You can manually restart the autopilot and it will now use the G5 logic in place of the G3X.

when I pulled the G3X breaker, the G5 showed the AP FD YD as flagged, and I could not engage them. Nor did the AP mode controller work.

I agree I should not have the re-cycle the AP CB to make it all work again

 

[PT20J]

34 minutes ago, rbp said:

when I pulled the G3X breaker, the G5 showed the AP FD YD as flagged, and I could not engage them. Nor did the AP mode controller work.

I agree I should not have the re-cycle the AP CB to make it all work again

 

I had something similar initially. When pulling the G3X breaker, the G5 would not pass PFT an would show continuous PFT and PTRIM indications and so the auto pilot would not engage. Updating the software to 9.0 fixed it. You might have the dealer update (or reload if you already have the latest).

[ArtVandelay]

My G3X requires 2 CBs to be pulled, in addition to the PFD breaker a GAD27 breaker need to be pulled (14V installation).

[rbp]

1 hour ago, ArtVandelay said:

My G3X requires 2 CBs to be pulled, in addition to the PFD breaker a GAD27 breaker need to be pulled (14V installation).

In order to reset your auto pilot?

[PT20J]

7 hours ago, rbp said:

In order to reset your auto pilot?

The GAD 27 provides power to 14V G3X/EIS during engine start brownout so you probably have to pull both breakers to shut down the G3X. But it shouldn’t have any other effect on the autopilot. 

[rbp]

Went to the Avionics shop today and this issue is now fixed.

 With the 10" G3X CB pulled, the FD/AP can be controlled from the G5, GFC500 mode controller, or the G3X 7" MFD

The tech said that all they did was upgrade the software, same as @PT20J