I have a D180 with Garmin GTX 327 and Echo UAT. In the last 6 months or so I've been having issues with the altitude reported to ATC. What they are indicating is always different from my actual altitude. Usually around 5-600 feet. Last flight they were getting the correct altitude for about a minute and then it went off. I've gotten a PAPR which showed no discrepancies, replaced the Garmin and gone through all the settings on both D180, Format 4. Garmin is set to Ch 1 Icarus out. Is there any way to check or confirm that the encode is, or isn't, the issue?
Thanks
Thanks