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Low level p4
779 24 2017-9-19
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Jonboy
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Flight distance : 320804 ft
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Multiple choiceVote: ( Up to 3 entry optional ), Total 16 people participate in voting View Poll participants

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2017-9-19
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ALABAMA
Captain
Flight distance : 9587785 ft
United States
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Almost fish bait.
2017-9-19
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Jonboy
lvl.4
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Ha Ha i will excuse the pun but no fish in the canal
2017-9-19
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Nigel_
Captain
Flight distance : 388642 ft
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Most likely, the place you took off from has steel piles to strengthen and waterproof the bank and once you where out of their magnetic field the compass lost accuracy.  If the water is higher than the land on that side then it is very likely.

Other possibilities are an iron mooring ring or a steel lined fishing platform, etc., etc.
2017-9-19
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DJI Susan
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Did the accident happen to your drone? Have you contacted the support to report it? Data analysis is recommended to check the exact reason.
2017-9-20
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MJLSTUDIOS
First Officer
Flight distance : 1540131 ft
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The water was flat (mirror like) which confused the bottom sensors. As the confusion set in, the drone reacted and as the drone lowered and the prop wash rippled the water and sensors now detected contrast and the drone rose. The water became flat again which confused the bottom sensors again. The drone said "enough" and quickly tried to land itself before you had the chance to drown it!
2017-9-20
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Mark The Droner
Captain
Flight distance : 2917 ft
United States
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I believe it's recommended to disable the VP sensors when you're gonna fly over water, isn't it?  
2017-9-20
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Jonboy
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Mark The Droner Posted at 2017-9-20 02:09
I believe it's recommended to disable the VP sensors when you're gonna fly over water, isn't it?

Yes so they say but have flown low level over lakes with inspire - phantom 3 and 4 with sensors on never been a problem until this one over a canal.
2017-9-20
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Nigel_
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Flight distance : 388642 ft
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If you don't know the cause, the log files would probably help to validate or rule out some of the possibilities, upload to http://www.phantomhelp.com/LogViewer/upload/
2017-9-20
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Jonboy
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MJLSTUDIOS Posted at 2017-9-20 01:50
The water was flat (mirror like) which confused the bottom sensors. As the confusion set in, the drone reacted and as the drone lowered and the prop wash rippled the water and sensors now detected contrast and the drone rose. The water became flat again which confused the bottom sensors again. The drone said "screw this" and quickly tried to land itself before you had the chance to drown it!

100% right  you got it Hope others can recognize this. No flight data logs needed :-)
2017-9-20
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Nigel_
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Jonboy Posted at 2017-9-20 06:12
100% right  you got it Hope others can recognize this. No flight data logs needed :-)

That can explain the poor positional hold initially, but I don't see how it explains the crash, it was not over the water when it crashed...

But the logs would help to confirm it, or discredit the theory...

Is this with the original or new P4 firmware, or a beta?
2017-9-20
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Jonboy
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Nigel_ Posted at 2017-9-20 06:28
That can explain the poor positional hold initially, but I don't see how it explains the crash, it was not over the water when it crashed...

But the logs would help to confirm it, or discredit the theory...

New Firmware. not just a crash but no control after intial hover. Flew again in new location no probs.
2017-9-20
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Simon Child
Second Officer
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I once flew over water which had circular expanding ripples. My P4 shot up in the air (trying to keep the gaps between the ripples the same, thinking that would maintain same height?) which was unfortunate (but not fatal) as it was flying under overhanging branches!

2017-9-20
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Jonboy
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Simon Child Posted at 2017-9-20 07:45
I once flew over water which had circular expanding ripples. My P4 shot up in the air (trying to keep the gaps between the ripples the same, thinking that would maintain same height?) which was unfortunate (but not fatal) as it was flying under overhanging branches!

Interesting stuff am just uploading new vid to show all is ok still with p4
2017-9-20
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DJI-Mark
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MJLSTUDIOS Posted at 2017-9-20 01:50
The water was flat (mirror like) which confused the bottom sensors. As the confusion set in, the drone reacted and as the drone lowered and the prop wash rippled the water and sensors now detected contrast and the drone rose. The water became flat again which confused the bottom sensors again. The drone said "screw this" and quickly tried to land itself before you had the chance to drown it!

When you fly over water bottom sensors most certainly are part of the equation. It's a reason why flying over water carries risk.
2017-9-20
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guardcim23
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DJI-Mark Posted at 2017-9-20 09:56
When you fly over water bottom sensors most certainly are part of the equation. It's a reason why flying over water carries risk.

You should use your drone for fishing
2017-9-20
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hallmark007
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Flight distance : 4785948 ft
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That looks very much like compass error magnetic declination. Can you put up flight log link below.

http://www.phantomhelp.com/LogViewer/Upload/
2017-9-20
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Dobmatt
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Keep us posted after log analysis ...
2017-9-20
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RedHotPoker
Captain
Flight distance : 165105 ft
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MJLSTUDIOS Posted at 2017-9-20 01:50
The water was flat (mirror like) which confused the bottom sensors. As the confusion set in, the drone reacted and as the drone lowered and the prop wash rippled the water and sensors now detected contrast and the drone rose. The water became flat again which confused the bottom sensors again. The drone said "screw this" and quickly tried to land itself before you had the chance to drown it!

You got a Symbian, for saying "s crew t his"...



Tough break. ;-)


RedHotPoker
2017-9-20
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Geebax
Captain
Australia
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All the guessing is pure speculation, until you post the logs to Phantomhelp, the actual cause will not be known. However in most cases where the pilot reports loss of control, the aircraft is actually in ATTI mode.
2017-9-20
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Labroides
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Flight distance : 9991457 ft
Australia
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When an airliner crashes, the investigators don't just sit around and list things that can make planes crash.
They look at actual flight data to see what happened.
Without looking at actual flight data, this whole thread is just people guessing and most/all are probably quite wrong.
If you want to find out what really happened, you are wasting your time until you look into the data.
2017-9-21
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RedHotPoker
Captain
Flight distance : 165105 ft
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Labroides Posted at 2017-9-21 19:49
When an airliner crashes, the investigators don't just sit around and list things that can make planes crash.
They look at actual flight data to see what happened.
Without looking at actual flight data, this whole thread is just people guessing and most/all are probably quite wrong.

I love watching vids of the drone flying over water, but fear that place, myself.

Thankfully, I don't live near the Pacific Ocean anymore. But I still miss it, 30 plus years later...


RedHotPoker
2017-9-21
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Nigel_
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Labroides Posted at 2017-9-21 19:49
When an airliner crashes, the investigators don't just sit around and list things that can make planes crash.
They look at actual flight data to see what happened.
Without looking at actual flight data, this whole thread is just people guessing and most/all are probably quite wrong.

Yes, this could be a learning experience for us all, but without looking at the data it is a missed opportunity.

The initial movement could be consistent with vision system issues but the crash doesn't match any vision system issue I can remember seeing in the past.

The crash does match compass issues and since this was a canal there is a good chance of a huge lump of ancient cast iron buried near the take off point and there is also a very good chance of modern steel bank reinforcement/waterproofing buried in the middle of the bank, both of which could cause a magnetic field related crash.

Without the data we will never know what caused the crash.
2017-9-22
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Mike-the-cat
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DJI-Mark Posted at 2017-9-20 09:56
When you fly over water bottom sensors most certainly are part of the equation. It's a reason why flying over water carries risk.

I guess some just have to live and learn
2017-9-22
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Mabou2
First Officer
Flight distance : 811253 ft
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United States
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Heh... maybe the decimal point was in the wrong place on your RTH altitude.
2017-9-22
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