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Crash - help me analyze flight data
405 19 2017-2-28 14:08:21
sd603
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Flight distance : 57816
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Hi,

Benign flight at dusk over the weekend.  I regularly fly around my lakehouse. Distance I can get varies, and I have experienced a number of lost signal return to homes. However, in this instance I lost signal and it never returned. I was surprised and lucky it crashed over land maybe 30 feet from the lake.  No idea what went wrong. Lots of false high wind warnings (extensively documented in threads for the p4p), wind was low.

Took some effort to download flight loflg off my p4p+ (aee my related thread, hint sync to dji and then open on app on uou phone and sunc to it.  Download from phone).  Here it is.

http://healthydrones.com/main?flight=23b937f9da1a78ae1c3ee533a9dc51e2&page_id=GENERAL

Thanks, appreciate any insights. Bird is on way to DJI. I have refresh, but my position is it is their issue.
2017-2-28 14:08:21
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taurus35
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United Kingdom
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Upload your log files here to get better flight details.
2017-2-28 14:28:40
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K9VXV
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What was the outside temp?
2017-2-28 14:35:01
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sd603
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Temp was 60 farenheight
2017-2-28 14:40:49
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hallmark007
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When you say false wind warnings how windy was it, those logs don't tell a lot just you lost signal at 8.00 and got signal back at 8.30s and it looks like your AC crashed at 8.58 you can see compass going wild presumably from crash.

You might learn a bit more if you upload logs to . http://www.phantomhelp.com/LogViewer/Upload/

That's tuff man how bad was the AC..
2017-2-28 14:51:31
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sd603
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OK, here is the DJI upload.

http://www.phantomhelp.com/LogViewer/OT04LM8QJ5TUKCSH51H8/
2017-2-28 14:52:12
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sd603
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hallmark007 Posted at 2017-2-28 14:51
When you say false wind warnings how windy was it, those logs don't tell a lot just you lost signal at 8.00 and got signal back at 8.30s and it looks like your AC crashed at 8.58 you can see compass going wild presumably from crash.

You might learn a bit more if you upload logs to . http://www.phantomhelp.com/LogViewer/Upload/

One of the arms was bent / busted pretty bad. Gimbal ok. Camera ok.

I rowed my canoe out to area I lost contact with it. While rowing I left remote on. To my surprise it reconnected. I saw from the feed it was on land looking at a house -- although it was upside down. That helped me find it.

I fully expected it crashed in lake.  I have one of those fishing rod recovery things on it, so assumed I'd be pulling it up from bottom of lake. At least I got ut back and it didn't damage anyone's property or people.
2017-2-28 14:57:45
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sd603
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Default RTH settings, as said earlier, I have used automatic RTH on signal loss in the past without issue.
2017-2-28 15:20:15
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sd603
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AlecW Posted at 2017-2-28 15:23
So you had a single loss, got control back and then had another signal loss a few minutes later?

Exactly.   I looked at the DJI version of the results and I don't see much -- but this is my first time looking at flight data.  The last record shows it at 178 feet high?

8m 59.8s        P-GPS        12satellites        178.5ft        11.3mph        3,315.9ft        61%        15.26V        3.816V        3.822V        3.815V        3.807V        0.015V
2017-2-28 15:30:48
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Labroides
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sd603 Posted at 2017-2-28 14:57
One of the arms was bent / busted pretty bad. Gimbal ok. Camera ok.

I rowed my canoe out to area I lost contact with it. While rowing I left remote on. To my surprise it reconnected. I saw from the feed it was on land looking at a house -- although it was upside down. That helped me find it.

Unfortunately this is one of those flight records that just stops in mid-air and doesn't clearly show exactly what happened but it does help eliminate some of the usual suspects.

We can see that the battery isn't an issue.
It was full at the start and still appears healthy at the end.
We can see that there is no terrain or obstacles that would have blocked signal at the altitude you were at.
And we can see that in the final 1.2 seconds of the flight record that the Phantom had started to fall from the sky.
In 1.2 seconds it fell and the speed recorded averaged 5.1 metres/sec, already faster than the descent speed for the Phantom and accelerating further beyond that.
All this happened while the left stick was in the centre position.

There's no hint of user error in the log and it's a good one for DJI to investigate.
They will be able to tell more from the data recorded on the internal SD card in the Phantom.
2017-2-28 15:47:57
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sd603
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Labroides Posted at 2017-2-28 15:47
Unfortunately this is one of those flight records that just stops in mid-air and doesn't clearly show exactly what happened but it does help eliminate some of the usual suspects.

We can see that the battery isn't an issue.

Thanks.  Do you come up with that drop speed by analyzing time between records and change in altitude?

Question -- if it hit a bird, could that have caused this?  I have zero evidence it may have been a bird, just wondering
2017-2-28 15:52:18
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hallmark007
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sd603 Posted at 2017-2-28 14:57
One of the arms was bent / busted pretty bad. Gimbal ok. Camera ok.

I rowed my canoe out to area I lost contact with it. While rowing I left remote on. To my surprise it reconnected. I saw from the feed it was on land looking at a house -- although it was upside down. That helped me find it.

It almost looks like it was going to start heading for home, but logs show at 8.58 178 ft it just fell out of the sky.
I suppose lucky for you it landed on terra ferma, I'm sure dji will have more info, good luck and keep us posted.
2017-2-28 15:55:52
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Labroides
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AlecW Posted at 2017-2-28 15:55
The one thing I don't get is why after the first disco it didn't start the go home mode.  In my experience it always does that and I get a notification in the log.

The only disconnection was at 7:50 whenthe downlink was lost for 5 seconds.
Losing downlink doesn't trigger RTH - you have to lose control signal.
2017-2-28 16:22:09
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sd603
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When these odd crashes happen we all want DJI to make us whole.  And, while it's tough for me to tell, it seems they often do.  What I wonder about is whether DJI can/has been held liable for consequential property or personal damages.  This is an emerging issue with driverless cars and insurance (think about it -- fully driverless cars should be 100% manufacturer liability).  DJI needs to be on top of this as they have a similar issue with all the failsafe technology built into our drones.

BTW -- I work in the insurance industry, and one thing I made sure of before buying a drone was that my $5mn umbrella liability policy covered my non-commercial drone usage -- it does.  If you hurt someone your $1-2k loss of drone is the least of your worries...
2017-2-28 16:59:48
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RedHotPoker
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Hope you have it figured out, and get back in the game soon...



RedHotPoker
2017-2-28 17:16:57
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DJI Natalia
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Sorry to hear about your crash.
Our engineers will help you analyze the flight data after the drone arrives, then let you know the reason.
2017-2-28 20:06:49
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lefgrter
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You can download flight logs from aircraft and open them with log viewer of Dji assistant app.
You can see there the sensor data, and many flight data (motor status, RC link status, GPS statud etc) that may help you.
2017-3-1 12:55:55
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Nigel_
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I think that there has been a power failure, the battery is shown still working OK but in the last second of log the motors loose power, it looses height, goes into an unstable spin, the GPS receiver looses satellites and then it looses the RC connection.

If it is under warrantee I think they will repair it or send you a replacement at no cost.

You were lucky not to land in the water there!
2017-3-1 13:55:23
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Nigel_
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sd603 Posted at 2017-2-28 16:59
When these odd crashes happen we all want DJI to make us whole.  And, while it's tough for me to tell, it seems they often do.  What I wonder about is whether DJI can/has been held liable for consequential property or personal damages.  This is an emerging issue with driverless cars and insurance (think about it -- fully driverless cars should be 100% manufacturer liability).  DJI needs to be on top of this as they have a similar issue with all the failsafe technology built into our drones.

BTW -- I work in the insurance industry, and one thing I made sure of before buying a drone was that my $5mn umbrella liability policy covered my non-commercial drone usage -- it does.  If you hurt someone your $1-2k loss of drone is the least of your worries...

Well you should be flying safely, which means not flying over people or property that may be damaged, so it will be hard to find them liable if it drops on top of someone.  Of course the law is different in different countries.

With DJI being Chinese you would probably have to use a Chinese court to get anywhere and I think that would not be worthwhile.

For the driverless cars, for the time being no driverless cars are available, they are only driver assist with the driver taking responsibility.  Even when driverless cars are available, the autopilot will just be a component and it won't be much different to finding the manufacturer liable for damage caused by any other component failure, failures do happen, especially in extreme circumstances, for example if you drive onto black ice and the anti-lock brakes don't stop the car when you use them and the steering doesn't steer the car, the manufacturer is not held responsible.
2017-3-1 14:04:52
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DJI Natalia
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Would you please provide me your case number? I'll look into it for you.
Please click on "Reply" button here so I can get a remind, thanks.
2017-3-20 18:24:12
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