Just an update I got a call from a senior Garmin guy. Garmin is very interested in this and have been research it. They want to schedule me to bring the plane into a dealer to get data off of it. One thing Garmin said is that they do use airspeed to correct from AHRS drift. But that if the airspeed is unavailable they will use GPS. I'm wondering if the winds were too strong for ground speed to be good enough to make that correction. I'm updating the logs from teh GI-275 here. You can see that as