Dear friends,

Yesterday I had my second Spark fly away. Unfortunately, this time I couldn't find the drone...
It flew around 50 mitres away from the home point totally fine (GPS signal all good, 19 sattelites). Then all of a sudden it went into ATTI mode, rose high up and flew over myself and in the opposit direction not reacting to anything, neither the pause button on RC nor the 'return to home'. After a while all the connection was lost...

After reading some forum discussions I found out how to "extract a TXT flight log.

Unfortunately, seems like it's in the forest..

I am just wondering WHY this type of things happen...

Yaw Error,
Weak GPS signal. Positional accuracy may be compromised. Please fly with caution.;
Aircraft GPS signal too week. Home Point not updated.;


Those are apparently the messages I was getting, not on the screen though. The only thing I received was Weak GPS signal...


Here is the report:
http://www.phantomhelp.com/logviewer/7DWO46492PQD3WP0OLDS/

Why do you guys think?

It is pretty unclear, but you might have had in interference with the compass. Did you calibrate before takeoff?

drewhoover Posted at 2018-4-2 05:10
It is pretty unclear, but you might have had in interference with the compass. Did you calibrate before takeoff?

I did calibrate before my previous flight.. which took place in the same location the same day..

@Jurza

I have seen the messages on the flight log, where these messages not also announced by audio while it is happening?

Pause button and RTH button rely on a good GPS signal and a compass that isn't giving yaw errors.  The pilot has to fly the drone In ATTI mode by working the sticks to keep it near himself and land on the runway.  Fly it like any other radio control airplane without GPS.

Gunship9 Posted at 2018-4-2 06:29
Pause button and RTH button rely on a good GPS signal and a compass that isn't giving yaw errors.  The pilot has to fly the drone In ATTI mode by working the sticks to keep it near himself and land on the runway.  Fly it like any other radio control airplane without GPS.

It did not react to anything!! no sticks no nothing!! Unfortunately....

Hi Jurza, sorry to read about your loss.

see my chart, it tells you all. Drone did react on your input, just see the up/dn stick inputs. Other inputs not really made made (some yaw), see the pitch roll angles of the drone. it just drifted away in ATTI mode.

cheers JJB

JJBspark Posted at 2018-4-2 07:20
Hi Jurza, sorry to read about your loss.

see my chart, it tells you all. Drone did react on your input, just see the up/dn stick inputs. Other inputs not really made made (some yaw), see the pitch roll angles of the drone. it just drifted away in ATTI mode.

Thank you.
Do you think it is worth going in the woods? Or is it a lost case? At least I wanna see the fiasco footage!

Jurza Posted at 2018-4-2 07:32
Thank you.
Do you think it is worth going in the woods? Or is it a lost case? At least I wanna see the fiasco footage!

Jurza,

I don't have an explanation for what caused the Yaw Errors that eventually forced it into ATTI mode.  This is something I think you should open a ticket with DJI on.  Maybe (or maybe not) they will conclude it is a warranty case and will provide a replacement for you.  That part is hard to predict.

In regards to the footage, if you were recording and you have the cache turned on in DJI Go 4, then you may have the footage on your phone.  I would check there.  I think I can speak for most of us here that we would also be interested in seeing the footage from your phone.

In regards to recovering your aircraft, I think that is going to be difficult to predict where it ended up.  The last recorded altitude was approximately 27m (88ft) high and moving at approximately 3.6m/s (8mph) and didn't show any signs of descending or slowing down.  It was also at 73% battery, so it could have continued on this trajectory and altitude for quite some time.  Not saying not to go look for it, just saying I won't even try to guess a projected search location.

In regards to the statements about the aircraft not responding once it was in ATTI mode, I agree with JJB.  Looking at your logs, there is a very clear correlation to stick inputs and resulting aircraft movements.  I think if you had some experience and knew to use the sticks to fly it home instead of trying to use RTH or the pause button while the aircraft was in ATTI mode,  there is a much better likelihood of a positive outcome.   In ATTI mode the aircraft was likely floating with the wind, but I think with positive stick inputs, the aircraft likely could have been directed to a more predictable landing zone.  

As I mentioned before, I would suggest you open a ticket with DJI (if you haven't already) and supply them with the FlightRecord log so they can try to interpret the cause of the Yaw Errors that lead to this scenario.

Good luck!  

kRx md Posted at 2018-4-2 06:28
@Jurza

I have seen the messages on the flight log, where these messages not also announced by audio while it is happening?

No, unfortunately no audio!! That's the sad thing.. i am really frustrated. I think I will contact DJI to get some answer about the issue. Why the yaw error occurred in first place?

Regards,

Jurijs

KlooGee Posted at 2018-4-2 07:58
Jurza,

I don't have an explanation for what caused the Yaw Errors that eventually forced it into ATTI mode.  This is something I think you should open a ticket with DJI on.  Maybe (or maybe not) they will conclude it is a warranty case and will provide a replacement for you.  That part is hard to predict.

When the aircraft is flying in ATTI mode, it will automatically land at its current location 3 seconds after the remote controller disconnects from the aircraft. If the remote controller disconnected at the end of the flight log, then it couldn't have traveled too far from the last recorded location.

msinger Posted at 2018-4-2 11:15
When the aircraft is flying in ATTI mode, it will automatically land at its current location 3 seconds after the remote controller disconnects from the aircraft. If the remote controller disconnected at the end of the flight log, then it couldn't have traveled too far from the last recorded location.

What does everyone/anyone make of the GPS errors?  Loss of GPS with 17-20 satellites seems unusual as well.  ( I'm still learning how to read these logs.)

WebParrot Posted at 2018-4-2 11:35
What does everyone/anyone make of the GPS errors?  Loss of GPS with 17-20 satellites seems unusual as well.  ( I'm still learning how to read these logs.)

It didn't lose GPS, it had YAW errors.  When that (or compass errors) occur and the aircraft is too high for the downward VPS sensors to work, then DJI automatically exits out of GPS mode and goes into ATTI mode.  In ATTI mode, it ignores all GPS data and thus is not able to hold its position.  It tries to hold its altitude and attitude, but it can't keep its location in a horizontal plane in this mode.  So it is susceptible to floating with the wind unless the pilot counters the movement by controlling it with the sticks.

msinger Posted at 2018-4-2 11:15
When the aircraft is flying in ATTI mode, it will automatically land at its current location 3 seconds after the remote controller disconnects from the aircraft. If the remote controller disconnected at the end of the flight log, then it couldn't have traveled too far from the last recorded location.

You may be right on that.  Is that documented somewhere?  I don't recall seeing that in the documentation anywhere and don't recall seeing that behavior in logs.  However, I very well could have missed it.

I know the Failsafe RTH scenario is invoked after 3 seconds if the home point was recorded, GPS signal is strong, and the compass is working.  However, I've not seen any documentation for autolanding in ATTI mode when the RC signal is lost.  

Jurza Posted at 2018-4-2 07:06
It did not react to anything!! no sticks no nothing!! Unfortunately....

I'm sorry to hear that your drone lost in the forest. Please contact our support and start a case: http://www.dji.com/support You can provide your flight records to our support for further analysis. Thanks for your support.

msinger Posted at 2018-4-2 11:15
When the aircraft is flying in ATTI mode, it will automatically land at its current location 3 seconds after the remote controller disconnects from the aircraft. If the remote controller disconnected at the end of the flight log, then it couldn't have traveled too far from the last recorded location.

What do you mean? it did not automatically land as you can see from the flight records! Ny phone (iPhone 7+) had a picture for the half of a fly away, but the RC obviously did not respond to 'return to home' and 'pause' and as I now found out it DID respond to sticks (which I did not know during the fly away).
half way into fly away the screen was shut..

I will contact DJI support and see what the say about the yaw errors.. Whatever that means.. Hopefully they'll solve it.

Good luck on your case. Hope DJI will action your concern accordingly

KlooGee Posted at 2018-4-2 11:54
You may be right on that.  Is that documented somewhere?  I don't recall seeing that in the documentation anywhere and don't recall seeing that behavior in logs.  However, I very well could have missed it.

I know the Failsafe RTH scenario is invoked after 3 seconds if the home point was recorded, GPS signal is strong, and the compass is working.  However, I've not seen any documentation for autolanding in ATTI mode when the RC signal is lost.

I've never seen that documented anywhere. That's what will happen though.

Jurza Posted at 2018-4-2 21:31
What do you mean? it did not automatically land as you can see from the flight records! Ny phone (iPhone 7+) had a picture for the half of a fly away, but the RC obviously did not respond to 'return to home' and 'pause' and as I now found out it DID respond to sticks (which I did not know during the fly away).
half way into fly away the screen was shut..

Once in ATTI mode, the Spark will only auto land if the remote controller signal disconnects from the Spark. That did not happen while data was being written to the flight log (since the remote controller was still connected at that point). It would have occurred after the last line of the flight log.

You cannot initiate RTH while flying in ATTI mode. Since the Spark is not using the GPS data, it's not able to find its way back to the home point.

msinger Posted at 2018-4-3 05:53
I've never seen that documented anywhere. That's what will happen though.

Cool!  I'll keep an eye out for it.  Thanks for the feedback.  Also, I appreciate you making your log viewer tool available for the community to utilize!  I've used it a lot to learn more about how the DJI aircraft function!

Jurza Posted at 2018-4-2 05:17
I did calibrate before my previous flight.. which took place in the same location the same day..

Okay that is interesting. What happens fairly often with fly aways is that they calibrate a few flights before, but change locations the next day. This often screws up the compass, and causes the fly away.

Jurza Posted at 2018-4-2 21:31
What do you mean? it did not automatically land as you can see from the flight records! Ny phone (iPhone 7+) had a picture for the half of a fly away, but the RC obviously did not respond to 'return to home' and 'pause' and as I now found out it DID respond to sticks (which I did not know during the fly away).
half way into fly away the screen was shut..

Any update on this ? I am planning to take my Spark to my up coming PEru trip. After seeing all these flyways I am really worry whether its better to fly my spark there.

Forgive my ignorance on this, but I'm eager to learn. What causes YAW errors? Is it magnetic interference, interruption of the GPS data, or pilot input?

msinger Posted at 2018-4-3 05:53
I've never seen that documented anywhere. That's what will happen though.

That sounds like sensible behaviour.... it would be great if someone from DJI could confirm.

Sorry to be THAT guy, but can someone please post a thread to a detailed (idiot proof) description on how to get the flight data please. I've tried searching for fly away posts but the search facility is 'limited' or at least my ability to use it! (This should really be a sticky IMHO its asked that often!)

MKPSG12 Posted at 2018-4-19 00:25
Sorry to be THAT guy, but can someone please post a thread to a detailed (idiot proof) description on how to get the flight data please. I've tried searching for fly away posts but the search facility is 'limited' or at least my ability to use it! (This should really be a sticky IMHO its asked that often!)

Look here

https://forum.dji.com/thread-114810-1-1.html

Thanks

MKPSG12 Posted at 2018-4-19 00:25
Sorry to be THAT guy, but can someone please post a thread to a detailed (idiot proof) description on how to get the flight data please. I've tried searching for fly away posts but the search facility is 'limited' or at least my ability to use it! (This should really be a sticky IMHO its asked that often!)

We also have a tutorial about exporting the flight data, check below. If there is any help needed, please let me know.

Thanks again, i was just about to ask how people have done this when their drone is lost but that video covers it too

I never never never did a compas calib. I flew @ several places( more then 60 times). I got the warning when I am close to some metal like a car. I shuted down the Spark and RC and boot it up some further away and flew away. A lot of  compass (yaw errors ) caused by sport mode and heavy rotating the Spark and some caused by interference of compass and still going to fly.

MKPSG12 Posted at 2018-4-19 00:25
Sorry to be THAT guy, but can someone please post a thread to a detailed (idiot proof) description on how to get the flight data please. I've tried searching for fly away posts but the search facility is 'limited' or at least my ability to use it! (This should really be a sticky IMHO its asked that often!)

I think most people on this board find the easiest way to check out your flight log is to use msinger's website that has a log viewer.  The site has detailed instructions for getting the logs off of your phone/tablet and uploading them.

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

So just to try explain what has happened or happens to cause these warnings and so called flyaways.

First is you sit your spark on the ground turn it on , lift it by hand and move it 90degrees , both your compass and IMU will move together 90 degrees this is how it should be.

If you put your spark on the ground and there is any magnetic interference, your compass heading will move because of interference, you will still be able to take off and when you clear magnetic interference you compass will move back on correct heading, you might think great, but no what now happens is because compass is correcting itself and moving IMU, it’s usuall followed by IMU exceptional heading yaw errors etc aircraft gets confused and you have data conflict, your spark cannot handle data conflict so it chooses to drop gps in favour of compass as spark cannot fly without compass but can without gps.
Your spark is now in Atti mode still controllable but difficult, it is most common to pick up interference from the ground rebar concrete metal objects nearby cars etc, there are other problems which can occur bad calibration although this is not very common.

You can always check your compass heading after you start your Aircraft by checking small red triangle in bottom left corner if it’s on the same heading your good to go.

msinger Posted at 2018-4-2 11:15
When the aircraft is flying in ATTI mode, it will automatically land at its current location 3 seconds after the remote controller disconnects from the aircraft. If the remote controller disconnected at the end of the flight log, then it couldn't have traveled too far from the last recorded location.

Hey msinger, while this may be correct we haven’t seen it documented, it would also be worth knowing because if aircraft goes to Atti mode and operator is having trouble controlling it, surely it would make sense to turn off RC and aircraft will just land. (So long as it’s not over people or water)

hallmark007 Posted at 2018-4-21 07:23
Hey msinger, while this may be correct we haven’t seen it documented, it would also be worth knowing because if aircraft goes to Atti mode and operator is having trouble controlling it, surely it would make sense to turn off RC and aircraft will just land. (So long as it’s not over people or water)

That's what makes forums like this great. We get to share undocumented gems with one another

Next problem is that Flight Data isn't shown when my Spark is attached to my computer (and my laptops Print Screen button is broke!)