I routinely get altitude readings on Flightaware that are significantly different from my in-flight readings from my altimeter. For example I think I’m flying at 3000 with the barometer set to ground reading and Flightaware reports 2800 or thereabouts on the track log. That a deviation that ATC would tell me about so I’m wondering what they are seeing. Sometimes both are pretty much in sync and I don’t understand why they vary from flight to flight.
Flight aware reports transponder or pressure altitude (ie 29.92Inhg or 1013.4mb).
FAA ground stations correct for this.
This was talked about a few days ago
Thank you. I did a search with the term “altitude” but this did not come up, perhaps since my question was not in relation to ADS/B.