GTN 650 Heading & Track Indication Issue

[Akash408]

We are experiencing an issue with the GTN 650 installed in our aircraft. On the ground, the GTN 650 does not display heading information, and the GPS track indication appears to be stuck or frozen. Once the aircraft becomes airborne, heading information is displayed normally.

Additionally, the pilot has reported a noticeable difference between the heading displayed on the GTN 650 and the heading displayed on the HSI. This difference was observed during flight and noted in the pilot’s log/observation report.

It is important to note that the HSI heading source is functioning normally, and the standby magnetic compass also shows consistent readings. The heading discrepancy is only observed on the GTN 650 display.

Please advise if this behavior could be related to ARINC 429 configuration, GPS track-to-heading transition logic, or any installation/calibration settings. Guidance on troubleshooting steps and recommended checks would be appreciated.

 

[rjones560]

The GTN650 has no ability to determine heading. For it to display actual aircraft heading, the information would have to come from some other source. Is there a magnetometer providing heading information to it? What does the rest of the installation look like? The GTN650 can determine what course the aircraft is making good when it is moving by itself, which is probably what the pilot is seeing in flight.

I have a GTN 650 in my RV10. The ARINC429 data is sent to the Dynon ARINC429 module which turns the signal into a format that can be displayed on the electronic HSI through the Dynon network. All 3 screens get the information through the network. However all heading information comes from the ADAHARS. The GTN650 has no way to generate heading information by itself.