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P4P+ Landed itself in a creek
396 7 2018-4-19
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Bullitt
lvl.1
Flight distance : 272700 ft
United States
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About a week ago I was piloting my Phantom 4 Pro + in a remote outdoors area, there was no apparent signal interference, good weather, a calm day. All conditions were well suited for flying.
I had been flying for about half an hour, landed, moved to a different location, and took off near a creek. As I was preparing my shot above the creek, the controller suddenly said "LANDING" and proceeded to descend where it was hovering. It did not attempt a return to home. I tried to manuver the aircraft and hit the cancel button several times on screen, none of which responded.

The drone landed in the creek, (which was about 2-3 feet deep) and after bobbing up and down in the water for about a minute struggling to land, it picked itself back up and then initiated return to home proceedure. It came down a little off course and tried to go through a small tree. My colleague grabbed it out of the air before it hit the tree and we recovered it successfully, of course now heavily water damaged.

I sent the drone back to DJI for repair and explained the whole thing, including the video clip it recorded during the incident which was not corrupted.
This is what they sent me:

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1. Unit took off with normal GPS signal, unit was responsive. 2. At t=278s,unit triggered rth due to lost RC signal. 3. At t=306s, unit returned above home and initiated auto landing. 4. At t=397s, unit clipped object in air during auto landing and fell. Conclusion: User was not familiar with RTH logic. Hazardous flight environment. No unit malfunction found.
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Their assessment of the events is about half-way correct. The unit did trigger RTH, and it did clip an object (the tree) but it did not fall and it clipping the tree was not what caused the damage, but they are completly ignoring the fact that it decided to land in the stream before it even tried to RTH. It was not a hazardous flight environment and I am familiar with how RTH works. This was clearly a case of aircraft malfunction and I have no idea what triggered it. I have tried to explain this to DJI tech support to no success, so i'm looking for other options.

Video clip of the event here:

2018-4-19
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Labroides
Captain
Flight distance : 9991457 ft
Australia
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the controller suddenly said "LANDING" and proceeded to descend where it was hovering. It did not attempt a return to home.
Whenever you launch you need to select a suitable location.
You need a location that will be safe for RTH, having consideration for the variable accuracy of GPS (no trees, water bodies etc close by).
You also have to understand that if RTH is triggered when the Phantom is within 20 metres of the homepoint, it will land in place rather than RTH.
So you want to make sure that the area is clear of dangers within 20 metres of the homepoint.

I tried to manuver the aircraft and hit the cancel button several times on screen, none of which responded.

When the aircraft is in RTH autolanding, you must cancel the RTH if you want to take control.
Fighting with the autolanding will usually end badly.
If you have no signal connection, cancelling is not possible.
This is why it is essential to select a suitable launch point that will be safe for an RTH landing.
If you do have signal, it is quicker to cancel by tapping the RTH button on the controller or flicking the flight mode switch from P-GPS and back again.

I would have to side with DJI's assessment: Conclusion: User was not familiar with RTH logic. Hazardous flight environment. No unit malfunction found.

It was not a hazardous flight environment and I am  familiar with how RTH works. This was clearly a case of aircraft  malfunction and I have no idea what triggered it.
It turned out to be a hazardous flight environment (poor choice of launch point - not suitable for RTH autolanding)
The aircraft performed exactly as it was programmed to.
Perhaps you now understand what went wrong

2018-4-19
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Bullitt
lvl.1
Flight distance : 272700 ft
United States
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Ok, why didn't landing protection engage and stop it from landing in the water? And why did it eventually pick itself up and return to the home point? Why didn't it just do that in the first place?

The big question is, why did it lose signal when I had perfect line of sight and there was no radio interference?

If/when I do end up getting an other DJI drone, this does nothing but make me want to turn everything off and fly totally manually. It was the auto features which totaled my aircraft.
2018-4-19
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Labroides
Captain
Flight distance : 9991457 ft
Australia
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Bullitt Posted at 2018-4-19 16:17
Ok, why didn't landing protection engage and stop it from landing in the water? And why did it eventually pick itself up and return to the home point? Why didn't it just do that in the first place?

The big question is, why did it lose signal when I had perfect line of sight and there was no radio interference?

It was the auto features which totaled my aircraft.
It was a combination of not knowing how the aircraft works and choosing a very poor launch point that was responsible for this incident.
Or .. as DJI said ...
Conclusion: User was not familiar with RTH logic. Hazardous flight environment. No unit malfunction found.
2018-4-19
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DJI Susan
Administrator

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Hi Bullitt, I managed to get your case number via the forum info. Per the case log, our engineers review your data again and support the previous analysis. Your case has been forwarded to the right team for follow-up, they will check and contact you in the working time soon. Appreciate your patience.
2018-4-19
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MavicAirFLJay
lvl.1
Flight distance : 4518 ft
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Honestly, if you hadn't d-icked around trying to take off your boots, you could have probably caught it before it even hit the water. I don't know how you didn't catch it before it hit the water lol.
2018-4-22
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Bullitt
lvl.1
Flight distance : 272700 ft
United States
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MavicAirFLJay Posted at 2018-4-22 19:29
Honestly, if you hadn't d-icked around trying to take off your boots, you could have probably caught it before it went under, I don't know how you didn't catch it before it hit the water lol.

A number of factors, as soon as I ran for it I was told it was too cold, too fast, and too slippery, and that I shouldn't go in by the person in charge of the property. So it was either potentially hurt myself or lose the drone.
2018-4-22
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MavicAirFLJay
lvl.1
Flight distance : 4518 ft
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Bullitt Posted at 2018-4-22 19:33
A number of factors, as soon as I ran for it I was told it was too cold, too fast, and too slippery, and that I shouldn't go in by the person in charge of the property. So it was either potentially hurt myself or lose the drone.

I get it makes sense, just didnt look deep and for the price of these damn drones, I probably would have ran in with out thought and died lol Sorry about your situation. Im not hearing positive things about dji Service even bestbuy said its not good. hopefully you have good luck!
2018-4-22
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