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Spark ATTI, Drift - Lost :(
1378 31 2018-7-4
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djiuser_zgwPd0J95Tqx
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United Kingdom
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Hi,

Any help appreciated. I was conducting a small flight and when the battery depleted RTH was instigated by drone. I allowed this to happen and expected the drone to return and land. However a number of errors presented on its RTH the drone overshot the RTH location at which point I tried to gain control without success. The find my drone app shows the location where GPS is lost however I know that it wasn't in that location. (That's where the flight line goes from blue to red)  I now see from the flight log viewer a red line, is that acurate or best guess? My other issue is it seems it was still in the air when the last log record came through so any idea where I would be best looking for the drone?

Many thanks,

Paul
2018-7-4
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djiuser_zgwPd0J95Tqx
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Here's the log http://www.phantomhelp.com/LogViewer/VO91SHHNQZ2RQ61DCWQ5
2018-7-4
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DJI Wanda
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Hello there. We apologize for what happened. We highly suggest contacting our support to start up a case and let our engineers investigate what happened to your drone. You may send an email to support.nl@dji.com or contact them to +44 2076603037.
2018-7-5
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JJBspark
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Hi Paul,

Last know position at 143 feet high drifting in the direction 270~275 with a speed of about average 10 ft/sec.
No obstacles so imo it landed safely, somewhere 143 : 10ft/sec descent = 14 seconds * 7 ft distance per second =  98 feet from last position

All values estimated, just walk in the direction 272, hope you will find your drone!!

cheers
JJB
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2018-7-5
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djiuser_zgwPd0J95Tqx
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JJBspark Posted at 2018-7-5 01:05
Hi Paul,

Last know position at 143 feet high drifting in the direction 270~275 with a speed of about average 10 ft/sec.

What made me think it hadn’t landed safely was that it dropped a few extra feet and then lost comms.

Search party out at the moment ....

Thanks for assistance.
2018-7-5
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Antipaxi
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Romania
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Such a nice clean log up until 3 min 28.5 sec.
You kind of flew it on low battery, but that doesn't explain the yaw errors.

And I really, really, don't get this message:
In Flight, working IMU encounters heading exception,please switch to atti mode if craft behave abnormally; Yaw Error
So the app tells you to switch to ATTI mode but you can't voluntarily switch to ATTI mode with a Spark. It's either a mistranslation or the software used for Spark was hastily put together from one of the ACs that can voluntarily be put in ATTI mode. Either way, it's confusing to get that message, one has no idea what to do in this particular situation.

Anyway, I think you should look for it on top of that building too, maybe it landed there. If you have a friend with a drone ask him for help to check the roof. It had 10% battery when it lost signal, so it might as well be there.
Hope you find it, man.

2018-7-5
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Antipaxi
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I just saw the hight it was at when it lost signal. 415.7ft and rising, at 10 % battery. I don't think your Spark made it down safely, dude.
Sorry.
Open a case with DJI, this might not be your fault.
Edited.

Sorry, 415.7ft was the distance from the homepoint, my bad. The height was 40 meters.
2018-7-5
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Sparky_17
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Canada
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looking at the log, your last altitude was 143.4ft and a distance 415.7ft from Home with 11% battery life left.  looks like it may have landed on the roof of the building or in the trees behind it.  Keep us posted ...
2018-7-5
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djiuser_zgwPd0J95Tqx
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Antipaxi Posted at 2018-7-5 08:15
I just saw the hight it was at when it lost signal. 415.7ft and rising, at 10 % battery. I don't think your Spark made it down safely, dude.
Sorry.
Open a case with DJI, this might not be your fault.

Hi,

The 415ft was from the RTH location the drone was at 145ft and dropping nicely when Comms failed. The speed suddenly slowed before the Comms failure also.

Paul
2018-7-5
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Antipaxi
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djiuser_zgwPd0J95Tqx Posted at 2018-7-5 08:23
Hi,

The 415ft was from the RTH location the drone was at 145ft and dropping nicely when Comms failed. The speed suddenly slowed before the Comms failure also.

Yeah, I noticed my mistake, I edited the post accordingly.
2018-7-5
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CHEFFY
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Yet another YAW error issue... I wish DJI would address this in a statement or something.
2018-7-5
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Mirek6
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Djiuser,

We have seen it before.
The reason you got yaw errors and, eventually, dropped to ATTI is because of elliptical trajectory of Spark when it is trying to go home.
The trajectory is caused by Spark fighting with wind blowing from SE.
Spark was calculating straight line of return to home point but it was forced to overcorrect due to wind and overcorrection resulted in confused sensors – compass, and gyroscope.
Speed error was caused by the fact that, while Spark was changing its headings (yaw) it was being pushed while it should have stayed put in one place. This caused firmware confusion. We have seen that before.
Yaw error followed when Spark started to fly back but its physical trajectory was different than commanded (calculated) trajectory. Firmware interpreted it mistakenly as disagreement between compass, IMU and GPS receiver and gave up. We have seen this before.

When you lost signal (at the end of red line) Spark was at the altitude of 44 metres and going down 3 m/s.
JJB is right in his estimation of time to land but I would extend my search further for two reasons:
•        Spark’s horizontal speed may have been as high as 6 m/s
•        Spark changed its flight path quite suddenly around 4m 19 sec. It could have changed it again – so do adjust your search area for it.

This change in path is very unusual given that you did not touch your sticks (actually you were yawing and trying to get it down – but no direction change).
Strong gust of wind from different direction? Something else going on?

In any case – I do not see your error. Something like this is a good cause for warranty claim. Contact DJI Support if you do not find your drone.

Mirek
2018-7-5
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CHEFFY
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Mirek6 Posted at 2018-7-5 09:22
Djiuser,

We have seen it before.

Nice explanation.
2018-7-5
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Mirek6
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Antipaxi Posted at 2018-7-5 08:10
Such a nice clean log up until 3 min 28.5 sec.
You kind of flew it on low battery, but that doesn't explain the yaw errors.

Antipaxi,

You say: In Flight, working IMU encounters heading exception,please switch to atti mode if craft behave abnormally; Yaw Error.

DJI GO app is the same for all DJI drones, so yes - this message is not for Spark and yes - it is a bug in DJI GO because it surely does know that it is flying Spark.

However, through my experience with log analysis, I know that I cannot trust messages 100%. They are quite often not in sync with what is happening and sometimes, like in this case, not relevant. So I treat them with a grain of salt and always compare to other metrics displayed in log.

Here all Spark' systems were totally confused. In confusion DJI GO may (and often does) display nonsense.

Mirek
2018-7-5
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Antipaxi
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Mirek6 Posted at 2018-7-5 09:29
Antipaxi,

You say: In Flight, working IMU encounters heading exception,please switch to atti mode if craft behave abnormally; Yaw Error.

Yes, but you are an experienced user. These type of "better ignore than act on it" error messages  are confusing for beginners or the type of people the Spark "dronie" is marketed towards.
It's not ok to display, as you very well putt it, nonsense on the screen of my device while I'm terrified that my AC not only doesn't obey my commands but also seeks happiness elsewhere.
2018-7-5
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djiuser_zgwPd0J95Tqx
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Hi,

I don't know how to quote but Antipaxi you hit the nail on the head with regards to "switching to atti mode" at the point where I should have been trying every effort to bring the drone down I was trying to find "ATTI Mode" on my phone in the software, this was only my sixth flight ......

I've searched the field, tree line and rooftop and no trace. I need a drone to search the field properly!

Is the consensus that it crashed or it landed safely because the last message was received at 143ft and when there was still 11% battery left.

Thanks,

Paul
2018-7-5
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djiuser_zgwPd0J95Tqx
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Also worth noting, there was very little wind yesterday, I had visual on the drone when it changed course and don't believe it was due to wind. You can see me trying to bring the drone back towards me and down also.

Appreciate all your comments.

Paul
2018-7-5
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Mirek6
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Antipaxi Posted at 2018-7-5 10:00
Yes, but you are an experienced user. These type of "better ignore than act on it" error messages  are confusing for beginners or the type of people the Spark "dronie" is marketed towards.
It's not ok to display, as you very well putt it, nonsense on the screen of my device while I'm terrified that my AC not only doesn't obey my commands but also seeks happiness elsewhere.

Yes - I do not dispute that. As a matter of fact I did point out it is a DJI GO app bug. I also provided a bit of input about other inconsistencies around DJI Go messages so everybody can learn.

No excuses for DJI though :-)
2018-7-5
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Mirek6
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djiuser_zgwPd0J95Tqx Posted at 2018-7-5 10:39
Also worth noting, there was very little wind yesterday, I had visual on the drone when it changed course and don't believe it was due to wind. You can see me trying to bring the drone back towards me and down also.

Appreciate all your comments.

Djiuser,

You say: "
Also worth noting, there was very little wind yesterday, I had visual on the drone when it changed course and don't believe it was due to wind."

We have seen that before as well :-).
Wind at a ground level and wind at 30, 50 or 100 metres are very different things.
Spark is very light and gets blown very, very easily if not in GPS or OPTI mode.

Unless we are talking magic, the elliptical trajectory on RTH is 100% consistent with the direction of ATTI fly away few moments later. But what is perhaps more important, pitch and roll of your AC is not consistent with powered flight in any direction. It is consistent with immobile Spark being rocked gently by the breeze and pushed by the breeze. My only observation which is inconsistent is sudden change in direction at the end - but again - gust of wind at 50 metres could have caused that.

You do have, in my opinion, good warranty case. Involve DJI if your drone is still missing.

Mirek
2018-7-5
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djiuser_zgwPd0J95Tqx
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I've logged this with support via their chat. Took a long time and didn't ask for logs so not sure what happens now!
2018-7-5
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Antipaxi
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djiuser_zgwPd0J95Tqx Posted at 2018-7-5 11:40
I've logged this with support via their chat. Took a long time and didn't ask for logs so not sure what happens now!

Support forwards it to the analyst, the analyst asks support for your files, support asks you for your files, you give them to support, support forwards them to the analyst and so on. Each interaction takes about 1 day. You don't talk directly to the analysts, they're demi-gods.
2018-7-5
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Hannes1
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Well Iam a beginner with about a dozen flights ,I hope I don't get my head shopped off. As I see it from a beginner, I would have not taken the AC so far away.
Battery levell was 48% at the beginning ,
after 1m20s the AC was 338.3ft high , battery was 37%
at 2m38s ,the Ac is 391.9 ft away and 338.3 high  battery was 27%
3m26.9 ,AC is returnig home at 20%   and still 339.2ft high and 386.7 ft away.

My Battery Warning is set at 30% and I don't have any problems with that , Cheers
2018-7-5
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djiuser_zgwPd0J95Tqx
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Hannes1 Posted at 2018-7-5 21:48
Well Iam a beginner with about a dozen flights ,I hope I don't get my head shopped off. As I see it from a beginner, I would have not taken the AC so far away.
Battery levell was 48% at the beginning ,
after 1m20s the AC was 338.3ft high , battery was 37%

Good news update received from DJI....

Dear Paul,


Thanks for your patience.

The unfortunate incident that occurred to your aircraft has been confirmed as a warranty case according to our data analysis.

If the aircraft couldn’t be retrieved, we would like to offer you a replacement, Spark(Lava Red) without charger and remote

I lost my SD card and it had propeller protectors on but still pleased!

Paul
2018-7-10
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JimFandango
Second Officer
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Good result! Hope you're up and flying soon!
2018-7-10
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JJBspark
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djiuser_zgwPd0J95Tqx Posted at 2018-7-10 00:06
Good news update received from DJI....

Dear Paul,

Hi Paul,

very good news from DJI !

enjoy your new Spark and many safe landings!

cheers
JJB
2018-7-10
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tomkrist
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Good to hear this tuned to a good case for you)
2018-7-10
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Mirek6
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djiuser_zgwPd0J95Tqx Posted at 2018-7-10 00:06
Good news update received from DJI....

Dear Paul,

Well - yet another case which proved that our suspicions and analysis was correct!

Thank you for letting us know. This information is very useful since it does confirm that we are on the right track here.

Mirek
2018-7-10
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hallmark007
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djiuser_zgwPd0J95Tqx Posted at 2018-7-10 00:06
Good news update received from DJI....

Dear Paul,

Just to give you a heads up on how compass error IMU exceptional heading and Yaw errors occur and how they are picked up.

The best way I can explain this is. If you put your Aircraft on the ground in normal circumstances, start it up, then lift it up and turn it 90 degrees to the right both your compass heading and IMU will both move together 90 degrees and no problems.
If you put your Aircraft on the ground and there is magnetic interference only the heading of your compass will change, your aircraft will still take off. But when it clears magnetic interference compass will then move to correct heading which you would think was great. But No, what happens is IMU is then conflicted and confused because of this sudden movement by compass, so you receive IMU exceptional heading warning, your aircraft cannot deal with data conflict so decides to switch to Atti mode dropping gps in favour of compass simply because aircraft can fly without gps but not compass.

While I can’t be certain you picked up interference from the ground or surrounding area it is the most common cause.

I’m pleased you got a warranty and hopefully more luck with the new one.
2018-7-10
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hallmark007
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This is a good exercise which can avoid many problems.

https://forum.dji.com/forum.php? ... &fromuid=260008
2018-7-10
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Antipaxi
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djiuser_zgwPd0J95Tqx Posted at 2018-7-10 00:06
Good news update received from DJI....

Dear Paul,

Congratulations, mate! Safe flying!
2018-7-10
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DJI Tony
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djiuser_zgwPd0J95Tqx Posted at 2018-7-10 00:06
Good news update received from DJI....

Dear Paul,

Glad to know that our team figured out for what was happened to your aircraft, however, I'm afraid that we don't have an option to retrieve the files in the SD card.  hope you'll be received the replacement aircraft as soon as it's ready to ship out.
2018-7-11
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ken2run
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the reason why i always check gps. fly safe always
2018-7-13
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