Help with cause of a Mavic crash into the sea.

[agrippa907th]

Hi all,

I've been a Mavic user for around 8 months, but I am new to understanding flight logs as this is the frist time I've really looked at one.

Last week I lost my drone in the sea in Thailand. I was flying in a small fishing village and at about 150 meters altitude it suddenly fell from the sky into the sea (after about a minute of flying).

I couldn't see any warning errors pop up except a compass error one and I need some help finding out why it just dropped from the sky. I noticed a propeller missing when I looked at the log, but.... I'm not sure how it could just pop off. There were no birds at all in the sky.

Luckily the sea was only about 2 meters deep and some fishermen were able to retrieve the drone (without the battery - it must has fallen off in the crash). However, due to being in salt water for about 30 minutes, the drone circuitry is dead

I've attached the logs (I'm sure to fully view them) and the video from the DJIGO app. The video of the crash from the microSD is unplayable (although the card is working fine)

NOTE: Not sure how to get the logs shown on this thread. Here is a dropbox link to the CSV. How can I make it visable to upload?

Dropbox - 2017-07-19_13-06-16_Standard.csv

This is the video from the DJI app (Sorry for the music - had to mute a lot of expletives )

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Thank you so much for any help you gusy can offer! I really appreciate it.

 

[Anthony Viscomi]

One thing that stands out in your statement is that the battery was not attached. I wouldn't think that a water impact should be hard enough to eject a secured battery.

 

[agrippa907th]

One thing that stands out in your statement is that the battery was not attached. I wouldn't think that a water impact should be hard enough to eject a secured battery.

I thought about a battery issue at first. The battery was installed into the Mavic as normal, and IF the battery had been the cause of the crash, surely there would be no video signal if the battery had come out. If you look at the video, there's a couple of seconds after it starts to fall

 

[Kilrah]

Looks like a hard mechanical issue, could have been improperly attached prop flying off, or just the prop breaking. Then battery being ejected by the resulting spin... but it would likely have had to be improperly clipped too for that to be possible.

 

[Therabitier]

Honestly, I would try their online chat support. I have a hard time understanding them over the phone, and although their whole support system is pretty bad... To me it seems like they just cant expand the department enough to match sales.
Did you accidentally do an emergency drop?

But, they do know ins and outs and can help you post and give them the log, this issue should be covered by their 1 year warranty, if not, let me know and I'll make sure to repost this video to share with the community as a warning.

As a response to the other comments, I think the blade, if it fell off, would either be from previous damage or manufacturer defect because it was up pretty far and not rotating nearly as fast as it did to ascend to that height. Second with the battery, I also believe that any issue with it would have been more likely to happen flying to the point you were at, rather than just hovering there.

My thoughts:
1. Manufacturer defect (Wiring shortage, hardware issue, glitch with satellites, etc.)
2. You held both sticks down at the same time (which causes your drone to do an emergency drop, would explain why video works).
3. Somehow your blade was in the perfect spot to go wrong upon descending only. I still don't think it was flip fast, I think it was spin downwards slower.

 

[Cyberpower678]

That CSV is useless. I need the original TXT.

 

[agrippa907th]

That CSV is useless. I need the original TXT.

Do you mean this one?

 

[Cyberpower678]

Do you mean this one?

Yep. I'm analyzing it now.

 

[Cyberpower678]

A quick question. Does the drone actually not power on anymore, or did you just assume it won't work because of the water. Water, even salt water, doesn't do much immediate damage when the drone has no power. It's only because of the conductive minerals in the water that drones die. Sure the salt will eventually corrode the electronics, but it doesn't happen immediately.

 

[Cyberpower678]

I took a look at the flight log. Something hit the drone and knocked it out of the sky. I assume your drone was missing a prop, or had at least a damaged one. It's also possible it wasn't secure and it came loose. In any event one or more props became compromised mid flight and the drone crashed.

EDIT: I forgot you said it was missing a prop.

 

[Enigma]

I think the problem starts earlier on.
At time index 3 seconds and also at 6 seconds, there is a very small but definite jellow effect.
Look at time index 10 seconds (photo), there is something in the air.

 

[Michael Ainsworth]

Was it the front right propeller coming off, if so this may be what you see in the video. Other possibilitie is bird strike but you did say there no birds around.
I would hazard a guess it's the prop coming off causing the crash.

 

[BudWalker]

I think the problem starts earlier on.
At time index 3 seconds and also at 6 seconds, there is a very small but definite jellow effect.
Look at time index 10 seconds (photo), there is something in the air.

I think you're right. There were two ascent phases. The first was normal. The second was associated with pitch instability.


At the end of the 2nd ascent it looks like a propulsion issue began indicated by the CCW spinning (consistent with either a rightFront or leftback propulsion issue) This was initiated by a pitch down and roll right which is consistent with a rightFront propulsion issue.


This sequence of events suggests (to me at least) that there was a prop issue that started with the 2nd ascent and finally came off at the end of the 2nd ascent. It wasn't caused by a midair impact like a bird.

A lost prop may be easier to claim as a failure that should be covered under warranty. Good luck.

 

[BudWalker]

Was it the front right propeller coming off, if so this may be what you see in the video. Other possibilitie is bird strike but you did say there no birds around.
I would hazard a guess it's the prop coming off causing the crash.

I must've been writing my post when you posted yours.

 

[KaiservonPoopChute]

Am I the only person that sees a bird at the very end of that video?

 

[Keule]

[Am I the only person that sees a bird at the very end of that video?/QUOTE]
Do you mean the whiteish W shaped something at 7 o'clock in the last frame?

 

[KaiservonPoopChute]

Yes! Is that a bird and if so could that be the cause?

 

[Keule]

Is that a bird and if so could that be the cause?

I doubt that this one caused the crash. The bird (if it's really one) is to low compared to the already dropping Mavic.
I stick with BudWalker analysis.

 

[agrippa907th]

I cant say for absolute certain, but there were no birds anywhere to be seen. There might have been a random one that I hadn't seen, but I don't think so.

One propeller had come off and one had snapped in half when I got it back from the sea.

A quick question. Does the drone actually not power on anymore, or did you just assume it won't work because of the water. Water, even salt water, doesn't do much immediate damage when the drone has no power. It's only because of the conductive minerals in the water that drones die. Sure the salt will eventually corrode the electronics, but it doesn't happen immediately.

I stupidily didn't do anything about the salt water on the electronics until a few days later (I'm not very experienced with electronics). I did turn it on a few days later after it had dried out when I got home (and got another battery), but as soon as I tried to power it on, but there was an immediate slight burning smell, so I turned it off right away.

Thanks for the help guys. I'll get onto DJI about repairs and what not.

 

[Cyberpower678]

I cant say for absolute certain, but there were no birds anywhere to be seen. There might have been a random one that I hadn't seen, but I don't think so.

One propeller had come off and one had snapped in half when I got it back from the sea.



I stupidily didn't do anything about the salt water on the electronics until a few days later (I'm not very experienced with electronics). I did turn it on a few days later after it had dried out when I got home (and got another battery), but as soon as I tried to power it on, but there was an immediate slight burning smell, so I turned it off right away.

Thanks for the help guys. I'll get onto DJI about repairs and what not.

Sorry to hear that. But yea, the flight logs most definitely support prop coming off mid flight, or something impacting it and knocking the prop in the process.