So I wanted to try RTL on my Spark. RTL is set to 100m. I have about 30% battery remaining and I push the rtl button. The Spark climbs to about 75m and then the alt display starts flickering between 75m and .4m. It is no longer climbing and just staying in place, I can see the copter visually and through the app. At this point I am watching the battery go under 20% and I am starting to panic. I cancel the RTL and try to bring it down manually, but it just will not come down even holding full down thottlle. I can still manuever horizontally, the altitude is still reading as only 0.4m and I surmise that it is only coming down at final landing speed. I try to change modes and re-enable RTL but nothing helps. As the battery approaches 0% I decide it will be better to have it fall into trees then my flat yard so slide it over a nearby group of trees. I am watching the battery voltage drop and at about 8V the spark starts to come down, rapidly... The trees break it's fall and it magically comes to rest unharmed in the tall grass under the trees.

I have the logs, and they show the alt starting at around 70m and slowly coming down at about .2 -.3 m/s. The mode appears to be stuck in "landing" the whole time.

So basically, it seems the Spark "reset" it's altitude during the RTL and thought it was only .4m above the ground (while actually at 75m) and thus stayed in landing mode and would not come down quickly. Coming down from 75m at .2 m/s would take 375 seconds (over 6 minutes)!

This spark has been aweful. Terribly range, video quality, constant app disconnect, and now this... I'm going to ask DJI for a refund.

I have the log files if anyone wants to look

Sorry to hear about that, we care much about your feedback, please export the flight log and data from black box, we'd love to help you analyze that.
You could connect the aircraft to a PC with Assistant 2 installed, run assistant 2, then get the data file needed, please refer to the screenshot below.
Please upload it to Dropbox and post the link here, thank you very much!

https://www.dropbox.com/s/l1e7ft ... 7_09-49-36.DAT?dl=0

Yikes. That does not inspire confidence. Hopefully DJI does right by you....and the rest of us in similar situations.

fansdbce68d7 Posted at 2017-6-24 21:06
I have the log files if anyone wants to look

You can upload your logs here at link below just click on it and follow instructions and come back here and post the link I will have a look, and by the way it's RTH not RTL.

http://www.phantomhelp.com/LogViewer/Upload/

Thanks for the link to that site hallmark007. Since my app kept crashing I have several logs for the same flight. Here they are in sequential order. You can see where I switch into RTH, then it get's "stuck" and I change the modes around a bit, then it gets stuck in "forced landing" mode and just refuses to come down for over 2.5 minutes. You can see the last log terminates at just under 8volts pack voltage as it begins to plummet to the earth Also interesting to note that the log show the correct altitude, but it said only 0.4m on my screen.

http://www.phantomhelp.com/LogViewer/8NYX5H6J3ZRN46QAPWF1/
http://www.phantomhelp.com/LogViewer/ETJQANSC95DG9CC2U20U/
http://www.phantomhelp.com/LogViewer/OJPILCX3JUI7K2HU5R6M/

From what i see ( i am realy sorry for your loss :]) if i fly to a point where battery gets to a 9% level its not so harmful :] you get to a 8V per Pack and it was flying still :]  As a matter of fact i was doing Tap Fly and it lost signal , but was in LOS , so i triggered RTH ... 3 times ... and nothing . So i just walk to it and gain control .. There is a bug in RTH and lost connection etc.

fansdbce68d7 Posted at 2017-6-27 11:39
Thanks for the link to that site hallmark007. Since my app kept crashing I have several logs for the same flight. Here they are in sequential order. You can see where I switch into RTH, then it get's "stuck" and I change the modes around a bit, then it gets stuck in "forced landing" mode and just refuses to come down for over 2.5 minutes. You can see the last log terminates at just under 8volts pack voltage as it begins to plummet to the earth  Also interesting to note that the log show the correct altitude, but it said only 0.4m on my screen.

http://www.phantomhelp.com/LogViewer/8NYX5H6J3ZRN46QAPWF1/

It's very strange it just seemed to be hanging in the air, it's almost as if it's just suspended in the air. Your height reading you say on screen 0.4 meter this is similar height that forced landing will halt at waiting for vision sensors to turn off and land.
I can see all the stick movements down on the throttle by you trying to get it down, just something to remember if you want to cancel RTH push up on throttle, although I don't think it would have changed things as you said you had cancelled RTH on screen.
I would almost certainly say it was some sort of technical malfunction.
Wind could also be a factor as your AC could never get directly over homepoint it was moving very slow which suggest strong wind, at 100 meters wind can be pretty strong so if it was wind then that would account for forced landing.
But at 16% battery you would have expected it to make it to the ground so it is puzzling and maybe only your dat file and dji will be able to sort it.
It is my guess that dji will offer a warranty on this.
Good luck.

Winds were calm, I think it never made it home because it was trying to climb to RTH alt and never made it. Then it switch to forced land which doesn't go for the home position.

fansdbce68d7 Posted at 2017-6-27 09:01
https://www.dropbox.com/s/l1e7ftnux89t2o9/DJI_ASSISTANT_EXPORT_FILE_2017-06-27_09-49-36.DAT?dl=0

Thanks, I have forwarded the data to our engineers for further analysis.
Besides, may I know you have contacted our tech support to send it in or not? If yes, what's your case number?

Would you please describe the environment  when it happened? Foggy weather or not?

Mine is doing this same thing now after the new update , NOT HAPPY ! was just fine before.

VPS glitch? If anyone has this happen, turn off VPS in the menu, see if it changes.