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DJI software bug surrounding authorised boundaries caused me to lose my drone to the sea

J4MEJ

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Yorkshire_Pud

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Welcome but to be honest and especially with this is your first post here, I can't help but think that if you want people HERE to analyse the flight you should post all the relevant information HERE i.e. add the story of what happened, but maybe I am odd, or out of touch, that way.
Either way, best of luck.
 
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J4MEJ

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Welcome but to be honest and especially with this is your first post here, I can't help but think that if you want people HERE to analyse the flight you should post all the relevant information HERE i.e. add the story of what happened, but maybe I am odd, or out of touch, that way.
Either way, best of luck.
Hi Yorkshire,

I fully appreciate that; however the reddit link embedded itself into my post, so the whole story with the links are all displayed on this website regardless.

Therefore there is actually no need to visit reddit to view the story or media, as all the details are in this thread.


Many thanks,

J
 
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LoudThunder

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I watched the video and lowered the playback speed to 25%. This looked like you simply flew your drone on a suicide mission. After numerous warnings that the winds were too strong to activate a Return to Home, and even a weak signal warning, You decided to fly north off the big island of Samson to that spit of land (just a pile of rocks), and then as your battery continued to deplete, you decided to fly east to another pile of rocks. You succeeded in flying your drone to its doom. Congrats!
 

J4MEJ

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I watched the video and lowered the playback speed to 25%. This looked like you simply flew your drone on a suicide mission. After numerous warnings that the winds were too strong to activate a Return to Home, and even a weak signal warning, You decided to fly north off the big island of Samson to that spit of land (just a pile of rocks), and then as your battery continued to deplete, you decided to fly east to another pile of rocks. You succeeded in flying your drone to its doom. Congrats!
From 65% battery I was trying to return to home, but there was a geo barrier I could not pass, which is why the drone travels in a straight line towards Puffin Island.

It took me a while to realise what was happening.

There were no strong wind warnings during this leg of the journey.
 

LoudThunder

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There were no strong wind warnings during this leg of the journey.

Yeah, during that last leg of the flight, you had the wind at your back…

But I beg to differ about the Geo Zone, I've included a copy of DJI's Geo Zone map of the area, and you were well outside of the St Mary's Airport Authorization Zone. I've superimposed the boundary markings onto your flight map and you did not invade the area. Now, I'm not saying something STRANGE did not happening here. Your flight path was not parallel to the boundary, but your flight path was perfectly straight, as if you were stuck inside a boundary…

map.png

But going back a ways, at 1:05 in the video, just as you started to fly south again, there was a Strong Wind Warning, at that time, the Flight Controller, calculating the Home Position and the Wind strength, reported only 10-minutes flying time left based on predicted flight characteristics and the remaining battery voltage.

And I do not know what possessed you to allow your little bird to get so far away with so little battery power, especially with all the previous High Wind Warning…
 

J4MEJ

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Yeah, during that last leg of the flight, you had the wind at your back…

But I beg to differ about the Geo Zone, I've included a copy of DJI's Geo Zone map of the area, and you were well outside of the St Mary's Airport Authorization Zone. I've superimposed the boundary markings onto your flight map and you did not invade the area. Now, I'm not saying something STRANGE did not happening here. Your flight path was not parallel to the boundary, but your flight path was perfectly straight, as if you were stuck inside a boundary…

View attachment 149989

But going back a ways, at 1:05 in the video, just as you started to fly south again, there was a Strong Wind Warning, at that time, the Flight Controller, calculating the Home Position and the Wind strength, reported only 10-minutes flying time left based on predicted flight characteristics and the remaining battery voltage.

And I do not know what possessed you to allow your little bird to get so far away with so little battery power, especially with all the previous High Wind Warning…
Thank you Thunder.

Did you compare my straight line to my purple line shown here?



This purple line is a custom geo zone, witch is an area I created to unlock the flight restriction zones.

I believe my drone is perfectly straight from 65% battery as a result of not being able to breach this geo fence (even though it could fly into the zone).


All the best,

J
 

Zbip57

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Did you compare my straight line to my purple line shown here?

Ah, I see what you mean now. It's confusing because your images show different Home Positions from different flights, so it was difficult to see what's going on. I overlaid your images to make them a little easier to understand.

The big yellow Home Point in the centre of your purple boundary unlocked authorization zone is from a previous flight. The flight route at the bottom of the image, with the various coloured tags, is where you encountered your problem.

Overlaid.jpg

The red boundary shows your unlocked authorization zone, which was still active at the time of this flight. Your flight started on the island outside of this boundary and your drone eventually crossed over the red line into the authorized unlocked zone, but then was prevented from crossing back outside to leave the zone. That left the drone stranded within the zone and unable to return to you.

Overlaid-2.jpg

I've never had the need to use any unlock features, so I have no personal experience at how they work. But I would think if you define a custom boundary within which you receive authorization to operate, that would create a custom perimeter within which you have permission to fly freely only if you remain within that perimeter.

You took off from a location where flight is already permitted, but crossed into the perimeter that you created, and then were prevented from leaving the boundaries which you earlier created for yourself.

I'm not sure you could call this a software bug, as it appears to have worked exactly as designed.
 
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J4MEJ

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Ah, I see what you mean now. It's confusing because your images show different Home Positions from different flights, so it was difficult to see what's going on. I overlaid your images to make them a little easier to understand.

The big yellow Home Point in the centre of your purple boundary unlocked authorization zone is from a previous flight. The flight route at the bottom of the image, with the various coloured tags, is where you encountered your problem.

View attachment 150045

The red boundary shows your unlocked authorization zone, which was still active at the time of this flight. Your flight started on the island outside of this boundary and your drone eventually crossed over the red line into the authorized unlocked zone, but then was prevented from crossing back outside to leave the zone. That left the drone stranded within the zone and unable to return to you.

View attachment 150046

I've never had the need to use any unlock features, so I have no personal experience at how they work. But I would think if you define a custom boundary within which you receive authorization to operate, that would create a custom perimeter within which you have permission to fly freely only if you remain within that perimeter.

You took off from a location where flight is already permitted, but crossed into the perimeter that you created, and then were prevented from leaving the boundaries which you earlier created for yourself.

I'm not sure you could call this a software bug, as it appears to have worked exactly as designed.
Thanks for the informative response.

This is exactly the issue I encountered.

Fair enough re: not a software bug, just seems a little silly that it couldn't bypass the custom parameter given the other side was a legal fly zone (just a warning zone).

DJI have come back to me now, and have said:

"If you believe the accident is not pilot-related, we can provide a paid data analysis service as per request if you would like to figure out the root cause of the incident.


Before taking such service, please be noted the following information.

1. The service cost is 120RMB/€ 50 per analyse, and it is not refundable;

2. Data analysis result is only for your reference on a technical level, it will not affect product assessment result or repairing fees.


DJI could still provide the repair service, but it will be a paid service".



So basically even if it turns out this wasn't my fault, I will have to fork out money not only to prove this, but also for repair fees.

Admittedly my warranty ran out 23 days prior to the incident; however I'd have thought DJI would accept a little more responsibility for this.

I'm not really sure what to do now.

I was going to upgrade to a Mini 3, but I no longer feel confident in DJIs customer service.

Unfortunately I am unable to purchase from Skydio as I'm based in the UK.

What are your thoughts for my next steps? Just suck it up?


Many thanks and best wishes,

J
 

Zbip57

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What are your thoughts for my next steps? Just suck it up?

I hate to say it, but it looks like there's no point in paying for any further analysis.

Perhaps others here can provide better opinions. I seem to remember seeing similar incidents reported in this forum, but I don't know what search terms to use to find it again.
 
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HoozierDroneDaddy

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I know when I used custom unlocks a couple years back (I had 9 of them set up for different areas in my region), you went into the controller and turned on the needed unlocked zone when you wanted to fly there. But you could also turn it off. If he had gone into the controller and turned his unlocked zone off, would that have let him cross back over the barrier, or would it have forced landed the drone similar to when you fly into one that your not authorized in?
 

Yorkshire_Pud

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Well done Bzip57 for an easy to follow explanation of the flight and the diagrams provided.

@J4MEJ some questions,
1) Is the islet under the drone around 6:53 dry land at high tide?
2) How quickly did you come to the conclusion that the drone was refusing to leave the authorisation zone?
3) If this occurred during the flight, why did you not attempt to reach other dry land?
I know hindsight is a wonderful thing but still it is probably something I would have thought of if I had deduced the reason for the behaviour.

One thing puzzles me, the stick mode is reported as zero but I am struggling to work out what the 8 directions are intended to do. How was the controller set up?
This stems from my wondering why the drone flew along the boundary between 6:56 and 20min+.
I think
LS-up = forward
LS-down = reverse
LS-R = right
LS-L = left
RS-up = climb
RS-down = descend
RS-R = clockwise yaw
RS-L = Anti-clockwise yaw
 
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J4MEJ

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Well done Bzip57 for an easy to follow explanation of the flight and the diagrams provided.

@J4MEJ some questions,
1) Is the islet under the drone around 6:53 dry land at high tide?
2) How quickly did you come to the conclusion that the drone was refusing to leave the authorisation zone?
3) If this occurred during the flight, why did you not attempt to reach other dry land?
I know hindsight is a wonderful thing but still it is probably something I would have thought of if I had deduced the reason for the behaviour.

One thing puzzles me, the stick mode is reported as zero but I am struggling to work out what the 8 directions are intended to do. How was the controller set up?
This stems from my wondering why the drone flew along the boundary between 6:56 and 20min+
1) to be honest I am not sure. I wasn't focused on this islet. Edit: going through some cached footage, this image shows it:
2/3) I was attempting to return at 65% battery. I only realised what was actually going on at about 20% battery. The drone was getting closer very, very slowly at about 0.1m/s, as it was following the purple line, and I was flying into it, rather that with it. Once I'd figured out what was going on, I thought 20% battery to try and reach land elsewhere was too risky and it would be inevitable that it would land in the sea. I was in quite a panicky state. I thought if I could land it on one of the rocks surrounding Puffin Island I could pick it up. Unfortunately the rocks were millimetres off and it went in the sea anyway.

Other question) the controller is setup as per one of the standard modes. I have it so that the left joystick does forward, backwards and side to side. The right joystick does elevation and twist.
Edit: your edit is correct.

I was just holding the left joystick forward for the most part trying to fight past what I thought was a strong wind which wasn't indicating to me, as it said it was doing 0.1m/s. I hadn't realised it was just going sideways really slowly and not actually coming towards me properly.

Hindsight is wonderful, and had I realised sooner, I would have attempted flying to Bryher or Tresco.

Feel free to ask any further questions.


Best wishes,

J
 
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Zbip57

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Hindsight is wonderful, and had I realised sooner, I would have attempted flying to Bryher or Tresco.

I'd say, under the circumstances, you did well to put the drone down in a spot where you could eventually recover it.

Far too many of us would either have totally panicked or simply pressed RTH and then been left wondering why it never came home.
 
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Yorkshire_Pud

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y. I only realised what was actually going on at about 20% battery. T
Ah, fair enough, can't fault you for that, panic does reduce the ability to think.
But if you get another drone and start using 'complicated' features I think it is advisable to practise them, and all the derivitives of them that you can imagine, in a safe place first before you fly the real flight.
I have been caught out too many times by unexpected behaviours i.e. behaviours that I did not know about, to now try something for the first time in a real flight.
Plus a lot of my flying would be over 'deep' salt water with no chance of retrieving a downed drone.
 
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J4MEJ

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Ah, fair enough, can't fault you for that, panic does reduce the ability to think.
But if you get another drone and start using 'complicated' features I think it is advisable to practise them, and all the derivitives of them that you can imagine in a safe place first before you fly the real flight.
I have been caught out too many times by unexpected behaviours i.e. behaviours that I did not know about, to try something for the first time in a real flight.
Absolutely. This is very sound advice.

I really had no intention of creating a zone ever, but the location I was in kind of required it else I wouldn't have been able to fly at the beginning of my holiday, so it was a spur of the moment decision to request permission from ATC and apply for the unlock via DJI.

Live and learn.
 

Zbip57

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I have been caught out too many times by unexpected behaviours i.e. behaviours that I did not know about, [...]

This forum is always particularly helpful in figuring out what went wrong and why. In hindsight, with enough people thinking about it, someone usually comes up with a logical explanation.

I had a couple of "moments" of brain-freeze when something unexpected happened during one of my flights, which only made sense much later when it was explained to me. Flying in the bottom of a narrow steep river canyon, my Mini lost GPS fix and switched to VPS mode where it relies on the bottom sensors to hold position while in a hover. I was surprised when I left the Mini hovering but it suddenly started drifting downstream as it was tracking the foam floating on the moving water surface. That's the very opening shot of this video. It moved all by itself.

Then later as I was flying above the waterfall and descending back to my takeoff location on the observation platform above the river, the Mini suddenly announced "Landing" and started descending toward the pool at the bottom of the falls. Yikes!!

That was later diagnosed as having been caused by the downward sensors detecting the mist coming off the falls, thus suddenly deciding it was less than 2ft off the ground, and because I was holding the throttle stick down at the time it triggered auto-landing. Luckily I had enough time to cancel that.

What confused me at the time is that I never actually had the throttle stick FULL down. Turns out, that's not required.

You only need to have been descending for more than three seconds, and the bottom sensors detect you're closer than 2 ft to the "ground", and at some point within those 3 seconds the throttle was lower than 85% down (which it was, even if never FULL down).

That sure was a revelation. I didn't know that before. But I tested it out in my driveway and confirmed it's true.

 

Yorkshire_Pud

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This forum is always particularly helpful in figuring out what went wrong and why. In hindsight, with enough people thinking about it, someone usually comes up with a logical explanation.
And that is one reason why I think forums are good background reading for everyone. We can often learn from the mistakes/mishaps of others as well as our own.
I would guess there are very few people, myself included, who would have thought, prior to this thread that it was impossible to fly out an authorised zone. That said I am 'scared' of restriction zones so don't fly near them.

There have been a number of things happen in my flights where I metaphorically said " oh this happened to so & so and this is what I should do". 'Their' experiences and this forum have been very useful in that respect.

One gem is Meta4's or Labroidies's, if you are in a jam, lost/dodgy connection etc. and do not know if the drone is in an RTH, switch the controller off and wait until the drone is in sight. I have done that in an experiment.

Interesting about the drone tracking foam, I had noticed something similar i.e. a drone using VPS seemingly following a moving target and wondered if that was what was happening. That too was a hindsight realisation of what I had seen.
 
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HoozierDroneDaddy

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For all the above reasons I installed Drone-Hacks on my M2P removing DJI Geo Fencing. I still follow FAA rules and use LAANC where needed. But I never have to deal with DJI to tell me when and where I can fly. DJI Geo fencing had caused many flight risks, some resulting in near losses, others losing their drones.
 

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