Kloo Gee
First Officer
Flight distance : 16783757 ft
United States
Offline
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Thanks for posting your FlightRecord for us all to try to parse and learn from. Unfortunately for me, they raise more questions than answers. The first one is that I find it very odd that the Flight Time in the video you recorded was only 4:11 and the actual FlightRecord has 4:45. As you noted, none of the time stamps match up between the video and the FlightRecord log itself. That is a first for me, but it could be that I just haven't looked that closely before. Not sure.
Also, I find this FlightRecord to be interesting because this is the first one I've looked at in depth where ActiveTrack was being used. In looking through the log, it is interesting to see the changes in pitch and movement throughout the log that don't have corresponding inputs from the pilot. So for me, it is hard to decipher what exactly the active track was attempting to do. To me though it is clear that there is at least a stiff breeze that is causing the aircraft to pitch and roll to try to compensate for it. But it isn't clear to me whether it was hard enough to actually knock it off course at a couple of different points (including the final movements) or if that was just due to some "interesting" ActiveTrack behaviors.
In the end, I think the final death blow was that line of site between the RC and the AC was very likely interrupted. You can see in the final moments, it lost connection for 4 seconds, followed shortly by a 1 second loss of connection, followed immediately by total loss of the signal (i.e. end of the log). I think it is around the 3:50 Flight Time mark in the video (YouTube video mark 1:55) where the pilot understands they are about to lose visual of the aircraft and decide to try to gain elevation by moving the right stick up. This can be seen in the FlightRecord logs at around the 4:24 mark where you can see the RcElevator value change from its default (1024) to a slightly larger value for a short time and eventually to 100% stick up (1684) about 8 seconds later. Unfortunately for the pilot, I think that since the aircraft was in ActiveTrack mode, it did not obey the request to gain altitude and maintained its ~160ft height.
Because the aircraft didn't gain any elevation, the RC and AC lost direct line of site and a short time later started having connection problems. At that point, it is hard for me to have a conclusion as to what happened because there isn't anything logged. It SHOULD have initiated an RTH after a 3 second loss of connection and headed for home.
The direction it was headed at the time of the final loss of connection, it seems like it may have been very near the same elevation as the top of that large black building. My guess is it either crashed into the top of it or just barely cleared it and continued on in the same direction past that building. If you were lucky enough for it to have cleared the building, I don't suppose you went back and checked the original home point on the off chance it may have done an RTH eventually. It had 64% battery left, so if it didn't crash right away, it eventually could have got its wits about it eventually and went home.
Having said all the above, there was a pretty stiff wind that day that appears to be out of the SW that coincidentally or not appears to be in the same direction of the final leg of the journey as the signal was lost. Again, it is hard for me to conclude if that is the wind causing that or ActiveTrack doing something "interesting".
Not sure I'm all that helpful, but it is an interesting case to look through. I wish you the best of luck in a positive outcome!
Google Earth's perspective of the flight from roughly the spot the pilot was standing...
Google Earth's perspective of final leg vs. tall black building. Not sure how accurate Google Earth's representation is.....
Did it hit it or just clear it?
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