Hello.
Last weekend I had my first long x-country, from Pennsylvania to Minnesota and back the next day.
On my way back I was on flight following and was talking to ATC.
I was at 7,500 feet, and the "pressure altitude" readout on my Garmin 327 was indeed indicating 7,500, (as well as both my Dynon D10 and my backup altimeter). But ATC told me that my mode-C readout was indicating 7,800 feet.
How is that? I thought that the readout on the pressure altitude window on the Garmin was the same that the unit was sending out.
Two more pieces of info: My encoder is an AT-150, and my pitot/static/transponder was just recently checked out (and passed) by an avionics shop here.
Anyone can explain the discrepancy?
Thanks
Last weekend I had my first long x-country, from Pennsylvania to Minnesota and back the next day.
On my way back I was on flight following and was talking to ATC.
I was at 7,500 feet, and the "pressure altitude" readout on my Garmin 327 was indeed indicating 7,500, (as well as both my Dynon D10 and my backup altimeter). But ATC told me that my mode-C readout was indicating 7,800 feet.
How is that? I thought that the readout on the pressure altitude window on the Garmin was the same that the unit was sending out.
Two more pieces of info: My encoder is an AT-150, and my pitot/static/transponder was just recently checked out (and passed) by an avionics shop here.
Anyone can explain the discrepancy?
Thanks