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DJI Spark Flight Data analysis help
1433 26 9-26 08:57
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MrC
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Flight distance : 138189 ft
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Hello

Can someone help me to analyse the data extracted from DJI Spark and DJI GO 4 app?



Normally DJI GO 4 app version 4.3.20 (4330) was used, and never had been a problem.
In this scenario though, the DJI GO 4 app version 4.1.22 (3037) was used.

Before take-off:
- Phone was connected to RC via OTG cable (as always)
- Everything seemed normal except for:
1) Red banner in top left corner on the screen showed "Weak image transmisson" - but the LiveFeed on the phone was perfekt though
2) Under WiFi details, no WiFi channels were showing at all. It was complete empty (but RC was green and LiveFeed on-screen was normal, except for above message)
3) DJI GO 4 app seemed to be showing the drone was a DJI Phantom 3?
- Retarted the drone and RC: Didn't change the above "signs"

Take-off:
- At takeoff the drone acted normally and HomePoint was set (Voice messaged confirmed it)

In the air:
- The drone was then controlled via the RC forward, and up. Distance aprox. 15 meters from take-off point and altitude not more than aprox. 5 meters
- The drone was then controlled via the RC up and when letting go of the stick (normally the drone should stop increasing altitude), but the drone kept increasing altitude to aprox. 8 meters.
- The drone was then controlled via the RC down, but didn't respond immediately but after aprox. 2-3 seconds it stopped increasing altitude at a height of aprox. 8 meters and then started to decrease altiude while voice message "Landing" was played, and message "Obstacle avoidance disabled" on the screen was showed.
- Red cross to cancel, on-screen was pushed multiple times, but it didn't work and controls on the RC didn't change the drones behavior.
- The drone landed in the water in one maneuvre without the user being able to cancel the landing. Total flight time: aprox. 1 minute and with a fully charged battery.

- Drone was recovered and after multiple days drying connected to PC to extract these data files.

Can someone analyse this data, and tell what went wrong? (except for the fact using an older app version, and the signs, and still went flying) ;)

Thanks


https://drive.google.com/open?id=1o75yL6IqHuKg1g0SIccRZkQuxseS7Z4F

9-26 08:57
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S-e-ven
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Flight distance : 3613448 ft
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How about this:

https://www.phantomhelp.com/logviewer/upload/

And after uploading your flight record from the Go4 app,  post the link to the upload here in your topic!
9-26 10:04
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MrC
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Flight distance : 138189 ft
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S-e-ven Posted at 9-26 10:04
How about this:

https://www.phantomhelp.com/logviewer/upload/

https://www.phantomhelp.com/logviewer/Z8P4W2XPUKJTVRHGGH68/#

"Forced Landing"

Please do explain how that's possible and what caused it
9-26 12:34
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DJI Tony
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Hi, we're sorry to know the situation that you have with your drone. Please sync your flight records and contact our support using this link: www.dji.com/support for further help. In addition to this matter, if your device has unfortunately fallen into water; try to rescue it while ensuring your own personal safety. Water damage can seriously affect the performance of the product, so you need to send the product back for inspection. Please see the details below. Thank you for understanding.

[Devices under warranty]
You can return the product via Online Repair Request, and data analysis will be provided. If your device is bound with DJI Care Refresh or DJI Care Refresh +, you can request a replacement device.
[Devices beyond the warranty period]
If your aircraft is beyond the warranty period, you can send it back via Online Repair Request, and we will provide you with a repair plan or apply for a discount.
9-26 15:52
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MrC
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Flight distance : 138189 ft
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DJI Tony Posted at 9-26 15:52
Hi, we're sorry to know the situation that you have with your drone. Please sync your flight records and contact our support using this link: www.dji.com/support for further help. In addition to this matter, if your device has unfortunately fallen into water; try to rescue it while ensuring your own personal safety. Water damage can seriously affect the performance of the product, so you need to send the product back for inspection. Please see the details below. Thank you for understanding.

[Devices under warranty]

Flight records now syncronised and uploaded.
Can you please take a look at all the provided relevant information, before sending the drone in.
Thanks
9-26 21:03
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JJB*
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Flight distance : 1176729 ft
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Hi MrC,

Had a look at your flight.

At about 8 barometer meters height VPS height starts to indicate low height ; 0.8 meters to 0.4 meters.When your SPARK gained height, VPS height did not follow that height wich normally it should do. See the VPS line in the chart.

In that situation (0.4 meter VPS height) with 100% down RC input SPARK will enter a ForceLanding. *
This is normal way of landing from that height, but not ofcourse when the VPS height is measuring an incorrect altitude.
ForceLanding "mode' can be stopped by 100% up, but you did not gave that up input, actually no input at all.In your text i read that SPARK did not react on RC input, in the log no signs of any input while it was landing.
So SPARK landed as it was commanded to do, but not intented to do by you ofcourse.

* this will also happens flying at any high height in the fog/clouds....if VPS height measuring the fog/clouds it will indicate zero, 0.1, 0,2....  100% down stick will force a landing, omg long way down to ground level if not stopped by 100% up stick.


Why VPS height did indicate wrongly?  dirt on the sensor, water on the sensor,  sensor error....
You are not the first person on here who looses a drone because if this (VPS height measuring incorrect, wich can be normal for low flying above water or other smooth surfaces).
Always check ( sure for low flying above water, as the risk is high when it goes wrong ) the VPS height in the GoApp if height correlates with the Baro Height.
And when applying 100% down input and the drone will not react directly ; it is a normal beahaviour to wait a little to enter ForceMode landing, so if you aware of that it can trigger you to know that a Forcelanding is activated. If not intented to do so, just counter it by 100% up stick.

PS for drones where you can disable Landing Protection, if disabled this Forcelanding will not happen. So mayby wise to do when you wanted to fly low over water.
Hope DJI can help you out.

cheers
JJB







analysis1.png
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9-26 22:59
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MrC
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I didn’t fly low low above the water. I had fly much lower than that above the water. The sensors are always clean. I inspect/clean that before every flight.

I increased the altitude by controller and when I released the stick it continued to increase altitude, which is why I pushed the stick down to stop it, but then it began to decrease altitude because of the forced landing command.  I pushed like 4 times on the cancel landing button on the screen but not sure I managed to push the stick up at the same time before realising what it was about to do, and whether Or not I could manage to catch it, but I couldn’t because it went so fast. I have the video of it too. From the SD-card. Lucky for me I had started a recording.  
9-27 02:49
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JJB*
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MrC Posted at 9-27 02:49
I didn’t fly low low above the water. I had fly much lower than that above the water. The sensors are always clean. I inspect/clean that before every flight.

I increased the altitude by controller and when I released the stick it continued to increase altitude, which is why I pushed the stick down to stop it, but then it began to decrease altitude because of the forced landing command.  I pushed like 4 times on the cancel landing button on the screen but not sure I managed to push the stick up at the same time before realising what it was about to do, and whether Or not I could manage to catch it, but I couldn’t because it went so fast. I have the video of it too. From the SD-card. Lucky for me I had started a recording.

oke, true   8 meters is not that low flying....but flying above water is tricky and users must know the forcelanding behaviour. (wich is not documented in the manual btw).
In your case the VPS height did measured wrong values...

But because of this VPS height and your 100% sitck down you did command your drone to land. (not aware of this!) To stop that landing is UP stick!

Not sure if the cancel buttons does stop a forcelanding, as this landing is normally only performed from a low height for very short moment.

cheers
JJB



9-27 03:09
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S-e-ven
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MrC Posted at 9-27 02:49
I didn’t fly low low above the water. I had fly much lower than that above the water. The sensors are always clean. I inspect/clean that before every flight.

I increased the altitude by controller and when I released the stick it continued to increase altitude, which is why I pushed the stick down to stop it, but then it began to decrease altitude because of the forced landing command.  I pushed like 4 times on the cancel landing button on the screen but not sure I managed to push the stick up at the same time before realising what it was about to do, and whether Or not I could manage to catch it, but I couldn’t because it went so fast. I have the video of it too. From the SD-card. Lucky for me I had started a recording.

How about you upload the video?
And how high did you fly over the trees?
Trees/ leaves can be seen as ground, from the VPS
9-27 06:05
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MrC
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I did not fly above trees, but only low plants in the water. I have never seen this behavior before and did not know about a force landing command. I only knew about force landing as a result of low battery. But why did the drone continue to increase altitude when I let go of the stick?
I could not cancel the landing, and pushed the cancel button on-screen but it did not respond, only like I was pushing to do a manual focus, hence the 4 messages of Metering mode........ As I said, I didn’t have time to think everything through, as I was shocked about the whole scenario and didn’t see it coming, and then it was too late.
I will upload the video later.
9-27 15:29
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MrC
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Aha. Funny it's the same app version I used...................
9-27 23:43
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MrC
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Is it because of the Visual sensors (VPS) measuring the drone suddenly out of the blue to be close to something underneath (like close to a hand or ground) while I pressed the stick downwards, it began to land??
9-28 00:00
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MrC
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But it's still pretty stupid that user is not being able to cancel the landing by pressing the button on-screen..
9-28 00:07
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S-e-ven
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Yes, see the stick moving to that column, 100% down
(You are in RC Mode 1, right?)
mode1.jpg

-"I did not fly above trees, but only low plants in the water."-
Is all that green in the picture just waterplants?
9-28 00:15
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JJB*
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Flight distance : 1176729 ft
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MrC Posted at 9-28 00:00
Is it because of the Visual sensors (VPS) measuring the drone suddenly out of the blue to be close to something underneath (like close to a hand or ground) while I pressed the stick downwards, it began to land??
[view_image]

Hi MrC,

A ForceLanding is executed only when:

Landing protection in ON
  AND
VPS height measuring approx. 0.3-0.5 meters [ flying actually at that height or VPS height measuring wrong height ]
  AND
100% stick down is applied for short moment.

In your flightlog at 36.7s 100% down stick, at 37.4 VPS height 0.4 meter, at 38.3 ForceLanding started.
So after 0.9 second (0.4 meters, VPS height met his condition for ForceLanding) and 100% down the SW understood that you wanted to do a landing....

In the log your RC stick inputs are followed bt the drone, no real sign of still climbing after releasing up stick.After releasing the up stick your SPARK climbed 0.5 meters, it need some time to stop the acsend. But i have seen quicker stops after releasing up stick. (and it drop a little too).
See the chart, check the blue lines and see the little peak and drop in the blue line.

Its not documented in the manual, so understand that you were little panicking what to do. Only thing to do is UP stick to cancel a Forcelanding.
And if you had know this behaviour not to give 100% down stick when flying above water.

But it took some time to start the actually landing...from 38s to 53s your SPARK hoverd at more or less the same height.
Mayby DJI can explain this and help you out.

BTW i think DJI should change the pre-conditions for a forcelanding. If baro height and VPS height are not approx the same * i would like to see a confirmation on the screen if i really want to land my drone. Hope that DJI will participate in this thread.

* possible when landing at a lower or higher ground than the take-off position. (and many more situations).But hovering at low height with VPS indication OK and Baro height not in line; well just one confirmation screen extra does help in not loosing crafts due to incorrect unwanted force landings!

cheers
JJB







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9-28 02:38
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JJB*
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MrC Posted at 9-28 00:07
But it's still pretty stupid that user is not being able to cancel the landing by pressing the button on-screen..

mayby yes, mayby not in the eyes of logic.

Normally this will happen only when landing manually to low hovering height, than 100% stick down.
Doing this is a action wich the user wanted to happen, so no need to cancel.
As the initiation is done by 100% down stick, cancelation is done by the same stick but UPwards.

But i understand what you are saying, will check if the pause button on the RC will cancel this, plus if the soft button in the app does a cancelation of this ForceLanding.

cheers
JJB
9-28 02:47
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MrC
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Thank you for your guys time and effort to comment and respond to my frustration. I can see that the sensor underneath the Spark did measure a wrong altitude several times. Switching between N/A and a wrong altitude. And it makes completede sense, that when it did measure barely 0.4 cm and me applying full down, it thought it should make a landing.

But why make a cancel button in the DJI GO 4 app if it can't cancel the landing procedure then? This scenario for me, was like something from a bad episode of Air Crash Investigation/Air Disasters, a combination of aircraft disbehaviour and pilot not understanding the mistake until it was too late. I hope DJI will use this particular case to improve the UI, software and hardware. I wish I could rewind the time and cancel the landing in time, by trying the tecniques you guys gave me.
9-29 13:03
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JJB*
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MrC Posted at 9-29 13:03
Thank you for your guys time and effort to comment and respond to my frustration. I can see that the sensor underneath the Spark did measure a wrong altitude several times. Switching between N/A and a wrong altitude. And it makes completede sense, that when it did measure barely 0.4 cm and me applying full down, it thought it should make a landing.

But why make a cancel button in the DJI GO 4 app if it can't cancel the landing procedure then? This scenario for me, was like something from a bad episode of Air Crash Investigation/Air Disasters, a combination of aircraft disbehaviour and pilot not understanding the mistake until it was too late. I hope DJI will use this particular case to improve the UI, software and hardware. I wish I could rewind the time and cancel the landing in time, by trying the tecniques you guys gave me.

Did you opened a case with DJI?

Hope you will not give up flying drones, to much fun to do so.

Pause button on the RC is much quicker to stop/cancel than soft button in the app.

cheers
JJB
9-29 22:57
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MrC
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JJB* Posted at 9-29 22:57
Did you opened a case with DJI?

Hope you will not give up flying drones, to much fun to do so.

Thanks, and no I won't stop flying drone. But my choice of brand may depend on how DJI will process this case and my economy - As this was a pretty sad loss.

Thanks for your tip - I will try use the pause function as the first choice next time something like this may occur - And then full stick UP and also switching to sport mode and back to normal mode......................
9-30 06:55
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DJI Tony
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MrC Posted at 9-26 21:03
Flight records now syncronised and uploaded.
Can you please take a look at all the provided relevant information, before sending the drone in.
Thanks

Hi, thanks for the prompt reply.  You may request for a data analysis via contacting our support using the link below. In addition to this matter, the request data analysis has a charge for the drone that is beyond the warranty period, however, if the drone is still within the warranty, it will be a free of charge with regard to the data analysis request. Hope that this would clarify your query. Thank you for your support.

www.dji.com/support
10-1 14:06
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dji_MODDER
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4.1.22 is a bad version for Spark (no otg) use 4.1.15 instead
10-2 05:43
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MrC
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What a great service from DJI!!
10-19 12:24
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Prairie Chicken
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Congrats, MrC. It looks like the system worked for you.

I had to look up what a liquid indicator is. There's a thread on the Phantom forum about it. Must be on all DJI products.

https://forum.dji.com/thread-22177-1-1.html
10-20 13:39
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MrC
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Prairie Chicken Posted at 10-20 13:39
Congrats, MrC. It looks like the system worked for you.

I had to look up what a liquid indicator is. There's a thread on the Phantom forum about it. Must be on all DJI products.

Yes, it’s used in devices like cellphones, and have been for many years
10-26 13:45
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MrC
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I had the new Spark in the air today. It was great to fly again.

I tested the behavior when the landing procedure has been initiated. (Landing in hand or on ground etc.) Pause button on the RC do not work. But switching to Sport mode will cancel the landing procedure and making the drone cancel the landing. This is great to know, if something like last time will ever happen again. If I just knew that, I could have prevented it from landing in the water.

I have learned so much after this incident and I am so happy that DJI replaced the drone and battery. 5 stars service.
10-27 04:48
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S-e-ven
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MrC Posted at 10-27 04:48
I had the new Spark in the air today. It was great to fly again.

I tested the behavior when the landing procedure has been initiated. (Landing in hand or on ground etc.) Pause button on the RC do not work. But switching to Sport mode will cancel the landing procedure and making the drone cancel the landing. This is great to know, if something like last time will ever happen again. If I just knew that, I could have prevented it from landing in the water.

Just:

In case it is a "critical battery" landing, ONLY throttle up will prevent it from going down!
And you can fly it with the other stick to safe places. As long there is still juice in the battery
10-27 06:25
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MrC
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S-e-ven Posted at 10-27 06:25
Just:

In case it is a "critical battery" landing, ONLY throttle up will prevent it from going down!

Yes, I have tried that sometimes, thanks
10-28 09:12
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