I'm doing some research on an aircraft accident (N150NE overrun at FFZ Nov 3rd) and I'm trying to understand some of the details of the data displayed. https://globe.adsbexchange.com/?ica...24&zoom=15.1&showTrace=2022-11-04&trackLabels It is pretty clear the guy was landing much too fast (he should have been closer to 90kts, not 117, over the fence). But if you look at the datapoints just before the overrun you see what seems to be an acceleration to 108kts briefly. Now he might have attempted a go around and then aborted it but that seems unlikely. So then I looked at his takeoff for that flight: https://globe.adsbexchange.com/?ica...m=15.3&showTrace=2022-11-04&leg=1&trackLabels If you zoom in and look at the takeoff roll it seems the plane gets up to 180kts just before the "ground" indication goes away then immediately decelerates to 120kts. That makes no sense: an Eclipse will usually lift off at about 90 kts. 120kts is a reasonable speed shortly after liftoff. So two questions: is the ADS-B speed report when on the ground reliable? And how quickly does the ADS-B indication change from ground to flight? I am not a very experienced adsbexchange user, please be gentle! Thanks!
He tried to go-around, but reacted to running out of runway too late. Turbines take time to respond to throttle inputs.
That's possible but 108kts is well above flying speed for an Eclipse with flaps down so if it accurate he should have been able to do the go around. And as a 14 year operator of an Eclipse I can tell you that our turbines are unusually quick to spool up (they are very small so have low mass to get moving). But that isn't really my question: the speeds shown on takeoff (180kts decelerating to 120kts) make no sense at all.
I was able to get resolution of this problem: the version of FMS/ADS-B in N150NE has a bug in the speed encoding in ground mode. So there was no go-around attempt it was just a software bug. (The FMS supplier fixed this in newer versions of the software.)
