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Critical Battery Auto - landing function
1878 23 2018-8-7
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SaCameron
lvl.2
Flight distance : 66388 ft

New Zealand
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Hi
I am a puzzled by the Autoland.

I lost my Mavic Pro in January, returning over water with some headwind - it initiated an autoland at 14% battery remaining - 870 m from home but only about 150 m from dry land - straight into the ocean without hovering with me frantically trying to run out and catch it (I could not override).  The painful thing is that it had enough battery power to make it to land (still had 10% on entering water).  This seems not a good design for flight over water in which an earlier than necessary autoland would cause loss of drone (as opposed to land).  I spent 4 days diving for it.  Has been with DJI for 7 months now - they want pretty much full cost and for me to pay shipping.  Very frustrating.

So why such an early or inaccurate non-customisable autoland feature?  Why was this designed like this?  Why cant it be changed for over-water flight?
thanks
scott

2018-8-7
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Bob Brown
First Officer
Flight distance : 3772907 ft
United States
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Sorry you lost it. The pause button should be the button that you mashed in that situation; always worked for me. It's like the cancel button. Works for RTH and critical battery landings until a certain point then you are screwed. If the battery was critical there is no way to stop it. DJI is trying to prevent a crash landing so this is how it is.
2018-8-7
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DJI Stephen
Super Moderator

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Hi there, we're very sorry for the inconvenience that you have faced. regarding with your concern yes the Pause button will work with that scenario, however, regarding to avoid landing on the water, unfortunately, we don't have that Feature yet but that would be nice Idea if our Product has that Feature, thanks for the suggestions.
2018-8-7
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PandaCheese
lvl.2
Flight distance : 253986 ft
United States
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The issue could have been avoided by setting the critical battery level to the minimal, 10%. Remember you still have a degree of control even when critical battery landing starts, like the manual says. You can attempt to hold altitude and navigate to a more suitable spot, within limits.

To put in some intelligence to avoid water landing may not be so straight forward, like how to reliably tell it's over water that's deep enough to be an issue? Should it hover at a low height for as long as possible? Pontoons may be the best answer for preventing a sinking to be honest.
2018-8-7
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GDL
First Officer
Flight distance : 1498789 ft
Singapore
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More accurately it should be avoided by returning before the battery becomes too low. The aircraft should returned close to landing zone around 30-40% power left for safety. Specially above water or place unable to recover need to keep more reserve power to handle unexpected situation. Fly to last juicy is looking for trouble.
2018-8-8
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Picanoc Jack
Captain
Flight distance : 6211614 ft
Canada
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thank you for that important info.
2018-8-8
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MrArcher
Second Officer
Flight distance : 401706 ft
United States
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x2, especially over water.  I mean, 14% battery left and anywhere near water is asking for trouble.  I'm amazed at how many people are willing to take these kinds of risks, and the number of people that lose that bet and wonder what happened.  I don't get it.
2018-8-8
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Wachtberger
Captain
Flight distance : 261509 ft
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''So why such an early or inaccurate non-customisable autoland feature?  Why was this designed like this?  Why cant it be changed for over-water flight?''

I am very sorry for your loss but your assertions are not quite correct and you could have easily avoided the accident by carefully reading the user manual and making yourself familiar with all settings of your aircraft.
The low battery autoland feature is neither early, nor inaccurate, nor is it non-customisable. Nevertheless, even if you set it to the lowest possible value there will be a point where autoland cannot be stopped any more for safety reasons since otherwise your AC would drop from the sky like a brick and could cause damage or even hurt people.
It is absolutely and solely your responsibility as pilot to fly with sufficient battery reserve at all times and no settings whatsoever can take away this responsibility from you. Especially over water you must also take possible winds into account that can slow down your return to a safe landing place. Take it as a painful lesson, as bad as it certainly feels.

2018-8-8
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gnirtS
Captain
Flight distance : 2993497 ft
United Kingdom
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Its designed to stop it running out of power in mid air and dropping from the sky like a rock.  I can't see why they'd want to let anyone stop that last ditch emergency feature.  It should never ever get to that stage.  You can set it to 10% which is very low.  You can also still control direction and pause the descent while its in auto land.  Sorry but you cut the margins far far too tight here - its not autolands fault.
2018-8-8
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G_Sig
Captain
Flight distance : 5975574 ft
Iceland
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What was the battery  % at takeoff?
If battery is not fully charged at  takeoff this is not the first time this happen.
We have seen this happen before and it won't bee the last time.
It you would upload your log we could see if this is something else.
http://www.phantomhelp.com/LogViewer/Upload/
2018-8-8
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SaCameron
lvl.2
Flight distance : 66388 ft

New Zealand
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Hi.  thanks for all the feedback.  
I do take responsibility.  
Somewhere between falling like a rock from the sky, and autolanding into sea with 10% battery remaining - there has to be a better way - if only over water.
The Battery was 100% on take off - I flew over the water - and kept a careful eye on battery.  RTH was pressed with 59% battery remaining.  There was no option to land at 30% as it was over water.    There was no ground level wind at take off.
Time
0:00- 8:55 flew to objective at 140 m height.
10: 58 RTH pressed- 59% battery remains.  No warnings. aircraft starts return- stays at 140 m.
High wind warning on return but average travel 20 km/hr.
17:45 - still travelling at 20 km/ hr.  14% battery remains
17:46- starts to auto land despite 14% battery remaining and 870m from takeoff (350m to land as is low tide).  Horizontal speed drops to zero without input from controller.  Pressing pause has no effect.
17:50 - vertical descent starts from 140m
19:03- aircraft descends straight into the water, without even a pause. No hovering.   9-10% battery remains!  Altitude = 0m. Aircraft enters the water.
19:03- 20:55 - aircraft continues to register negative altitude as it is underwater and sinking to the bottom.  Battery dies quickly.
20:55- battery dead as is 2.3 m underwater.  Transmission ends.
I cried.....
So what did I learn from this tragedy?  1. watch for any wind and dont try any long flights unless completely still.  2. Dont do any significant flights over water 3. Never go < 30% battery 4. Train for what to do if the aircraft starts to autoland in a bad place.
It has been 7 months that I shipped the drone to DJI - endless back and forth.  I have offered to pay up to 1000 for a refurb - acknowledging my responsibility.  They want more than a new drone (and dont reduce the amount as it is drone only - not controller - that I am after).  I just asked for the broken one back so I can conduct a proper burial (at sea..) - they want me to pay 100 for them to ship it back.  The interaction with DJI and false hope dashed repeatedly has been for me as traumatic as the initial loss...  

scott
2018-8-8
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rolling56
Captain
Flight distance : 138310 ft
United States
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wow sorry to hear about all this. I would be heartbroken if i had that happen to one of my 2 Mavic Pros.

Like others said the cancel button is the one to hit but i have seen people say that didn't work for them but when you're frantic things happen differently sometimes.

And now they want $100 to send it back makes the knief twist a little more.
2018-8-8
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SaCameron
lvl.2
Flight distance : 66388 ft

New Zealand
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Thanks mate.   Heartbroken was a good description - I had run out into the ocean to try to catch it, then spent 4 days diving for it.  A mourning process ensued.  DJI will not ship to NZ so ask for $$  - which at 7 months now does feel like one last trauma.  The painful thing is that last week I was sent an email saying here is the quote to repair your MP, then 2 days after I paid this they wrote to tell me that this was not for any repair - just freight to send me back the broken drone.  Ouch....
2018-8-8
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GDL
First Officer
Flight distance : 1498789 ft
United States
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Just keep in mind your aircraft should landing (not RTH) on 30% battery not 20% or 10%. That will save you from trouble. Like a real pilot the last 20% fuel in tank should never be used. This will also keep your battery use longer time.
2018-8-8
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CA Mavic Pro
First Officer
Flight distance : 639652 ft
Lebanon
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GDL Posted at 2018-8-8 19:48
Just keep in mind your aircraft should landing (not RTH) on 30% battery not 20% or 10%. That will save you from trouble. Like a real pilot the last 20% fuel in tank should never be used. This will also keep your battery use longer time.

Totally agree
2018-8-8
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Blizzard
Captain
Flight distance : 173734 ft

Belgium
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Sorry for your loss, and, I know, afterwards it is always easy to say what you should have done, but if, after the message of high wind, you had started flying lower, maybe, you could have reached the coast.
2018-8-9
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SaCameron
lvl.2
Flight distance : 66388 ft

New Zealand
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Blizzard
Thanks and Good point.  I should have descended from 140m to 30m and I suspect this should have reduced wind and extended the time to auto land, which I suspect factors in height.  Make this lesson 5.
Well lesson learned.
Unfortunately DJI support has decided to take 7 months dealing with the case so all of my enthusiasm for the drone has been diminished by a terrible service division more intent on saving face than customer care, so I may not get to implement my lessons learned on a new drone.  

Cheers scott

2018-8-9
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rwynant V1
Captain
Flight distance : 4316342 ft
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United States
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Panda

Your words:
"To put in some intelligence to avoid water landing may not be so straight forward, like how to reliably tell it's over water that's deep enough to be an issue? Should it hover at a low height for as long as possible? Pontoons may be the best answer for preventing a sinking to be honest."

Hmmmm.......Thinking out loud here......HMmmmmm

GPS       Location     On a map    Couldn't the location note the AC is over water,  without WATER being the factor?  GPS Location on the map.....OVER WATER.  If the AC could do that, then it's true mission would be to aim for LAND,  theoretically the Home Point......or at least LAND on the MAP of any kind.

For instance, on the map, your are over water and the HP is 600meters away and you reach critical low power.  The AC could in theory aim for the pennisula that is just over there at 150meters.  Yes you'd have to walk to get your AC, but it's not in the drink.........

Back to regular scheduled program......

Randy
2018-8-9
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gnirtS
Captain
Flight distance : 2993497 ft
United Kingdom
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Neither Here or Google maps provide any methods in the API to tell "water" from "ground".
That and in lots of places you wont have access to working GPS maps anyway.

And where do you draw the line?  If its over a thick forest, a lake, an ocean or a mountain cliff the drone is just as lost.

Ultimately it just needs the operator to engage brain and fly conservatively and remain aware of conditions.
2018-8-9
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rwynant V1
Captain
Flight distance : 4316342 ft
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United States
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gnirtS Posted at 2018-8-9 10:24
Neither Here or Google maps provide any methods in the API to tell "water" from "ground".
That and in lots of places you wont have access to working GPS maps anyway.

Have you flown, and run into a yellow zone on the DJI Flysafe Maps?

If you have, then you also know your AC will slow down and STOP at that yellow line on the map. It will NOT cross that line, unless you have Unlocked it. There are thousands of Yellow No Fly Zones that are ALL GPS located.

I am NOT saying to stop the AC from flying over water, but just to know where the shores are on the GPS located map......  That way, maybe the shortest path to land is safest.......keeping in mind you should be able to see where the AC went on your phone/Tab in this critical situation.

Randy
2018-8-9
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Koelkop
Second Officer
Flight distance : 22814806 ft
South Africa
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Are you sure you could not counter the landing? At the auto landing stage you can press the left stick up to stop it from descending. That is how it has worked for me everytime I went there.
2018-8-9
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gnirtS
Captain
Flight distance : 2993497 ft
United Kingdom
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rwynant V1 Posted at 2018-8-9 10:43
Have you flown, and run into a yellow zone on the DJI Flysafe Maps?

If you have, then you also know your AC will slow down and STOP at that yellow line on the map. It will NOT cross that line, unless you have Unlocked it. There are thousands of Yellow No Fly Zones that are ALL GPS located.

And as i said?  How is it going to do that?  The API for Here and Google dont offer any method of telling what the terrain type is.

NFZs are stored in a (relatively small) database and use simple geometric shapes and a radius (most are simple circles).

Theres absolutely no way for the DJI software to get the terrain composition from the maps and certainly no practical way to code all the worlds areas of water accurately enough and store on the aircraft database.

There's a far simpler solution as well - the operator actually engages their brain and thinks for themself rather than relying on automation to protect them from their own screwups.

2018-8-9
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RadioFlyerMan
lvl.2
Flight distance : 2594032 ft
United States
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Koelkop Posted at 2018-8-9 11:32
Are you sure you could not counter the landing? At the auto landing stage you can press the left stick up to stop it from descending. That is how it has worked for me everytime I went there.

My same experience. I was in auto land, had my eye on a clearing, then recalled from a YouTube video that you can push up to gain altitude. Didn’t have to press cancel.  Landed with 5%.
2018-10-28
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DJKOR
Second Officer
Flight distance : 2035676 ft
Australia
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Sad lesson to learn. I once experienced a similar thing and in my panic while the aircraft was decending, I held the throttle up in an attempt to gain altitude in the hopes I could make it home. To my surpirse, it climbed at a slow rate and I made it back. Later on I read that this is was in the manual:
Screen Shot 2018-10-29 at 5.28.20 pm.png

I guess it is just unfortunate that you didn't manage to stumble across this in your process of trying to get back to land, but it is good to know for future reference.
2018-10-28
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