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Finley Atherton
06-26-2020, 12:16 AM
Two of us in Australia with GTN 650s and Propilots have the same issue where the Propilot loses GPS input in missed approaches ending with “Vectors” on the GTN Flight Plan page. Using Inverell as an example:

https://i.postimg.cc/vZgvLxGt/3-DB98015-0901-4-EF7-B06-E-CF01-FAAB99-C8.png

At IVLSH in the missed approach the Propilot starts the left turn to 173 degrees but within a few seconds it displays No GPS and goes into wings level mode. The GTN continues to work normally with full satellite reception. We discovered this in VMC but it would get your attention in IMC as there is no immediately obvious way to get GPS back to the Propilot.

After further investigation it seems that approaches ending with “Vectors” on the GTN Flight Plan page have this issue.

https://i.postimg.cc/YSyGXb84/91219670-DCEC-4-F92-A713-296-D42-CF7-EC0.png

After trial and error we found that removing the approach from the GTN Flight Plan page restores GPS to the Propilot. Our interim solution is to load the approach and then remove the “Vectors” box from the end of the approach on the GTN and at IVLSH turn manually or with the Propilot in Course mode.

We have contacted Chuck at Trio and confirmed our wiring and settings. He thinks it is an issue with the serial link from the GTN and would need to analyse the serial data to see what’s going on. Anyone else had this issue or is it peculiar to Australia?

Fin
9A

BobTurner
06-26-2020, 01:07 AM
I don?t know. But I would start with Jepp or Garmin or wherever you get your 650 navdata from. I notice the chart says ?track?, which the gps/autopilot should be able to do, but the display data point says ?heading? which the gps/Trio cannot do.