I can confirm also it all works as advertised. I have the Garmin Aera 500, FSX, and Windows 7.
There is one limitation I have found in what appears to runway 'off-set' after flying a short while, and I don't know what causes it. For example, placing the airplane on the runway, holding in position for takeoff, and re-setting simulator mode in the Garmin results in a perfect alignment. I can see the lat/lon in FSX matches lat/lon on the Garmin position page, as does the visual on both screens.
If you fly a simple traffic pattern, and re-land, the position of the airplane after landing can be as much as several hundred feet off. I have noticed the new position is not always consistent, sometimes it can be within 50 or 100 ft, and on different parts of the runway. If you re-set 'simulator mode' on the Garmin position page, the alignment is correct.
If we assume the Garmin is operating in a real airplane, WAAS enables accuracy to within 10ft lateral with enough satellites operating, and you need to use your pressure altimeter in the aircraft for vertical guidance, especially on hot days. So for practical purposes, steering mode is always spot on in the real airplane. I have many real world tracks that confirm this fact when imported to Google Earth, I'd swear the lateral accuracy is down to 1 foot.
In simulation mode, I would assume there should be zero errors. I have confirmed Garmin AV IN requires 9600 baud, but I am wondering if a 100 ms interval is too fast, perhaps 200ms might produce better results since the screen re-fresh time is 5 hz.
But I am only guessing, wondering if anymore might have the answer as to what would cause the lat long to be correct in the beginning of the session, then be so far off in only 5 minutes of flying.
UPDATE 1/24/14 : Using interval of 200ms vs. 100 does not improve the "offset" problem. So for now, I am just re-setting "simulator" mode in the Garmin prior to landing to force a re-alignment at the critical stage.
Pretty cool stuff!
