SW 9.72 - Average Flying Ground Speed is off

The F5X surprisingly tracked GPS quite well during my flight from Houston to St. Louis. While distance appears fine, the average ground speed is off.

Also does anyone know if I can prefer GPS elevation in the recorded tracepoints rather than barometric? Then, elevation profile would look correct.

https://connect.garmin.com/modern/activity/2919544242

0 Former Member over 6 years ago

Look at the bottom of you dashboard:

149.4 km/t
Gennemsnitlig fart på jorden
665.7 km/t
Gennemsnitlig bevægelsesfart på jorden

This is translated to Danish, but says:

149 km/t - average speed on the ground
665.7 - average moving speed on the ground.

The latter looks correct - like it is counting the average speed during take-off and landing in the first line.

Given that say a B737 has an average landing speed of about 155 knots / 290 km/t, the 149 km/t kind of make sense...

0 saeedi over 6 years ago

I see that. But the speed chart doesn't mesh with the display. I never go over 150mph in the chart yet I was flying anywhere 440 to 550mph. There might be a type of overrun.