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Crash in Amazon Jungle - Problems with maximum altitude
885 12 2019-5-7
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LilyValley
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Flight distance : 141220 ft
Netherlands
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Hi all dji fans,


I'm  new to this community, learning a lot from this forum. I have a few  questions that I couldn't find a quick fix to on this thread, so here it  goes:

I recently got a Mavic Air, using it as  an art and technology teacher to inspire kids in filmmaking and new  techniques. And for fun, of course.

When I planned a trip  to the Amazon rainforest I didn't have to think about it, I was  bringing the drone. It was a fantastic experience, and the birdseye view  definitely opened up a whole new perspective. Made some beautiful  footage, stills etc. Even spotted some Toucans in the canopy 11m above  the ground with the drone!

The farthest in the  jungle I had 20 satelites, so the signal was even better than in my  hometown. I had an amazing week flying the drone every day, till all  batteries were empty.

Then there was this one time I  almost hit electricity wires that werent visible because of the  backdrop. They tend to dissapear in the surroundings, very tricky! My  spotter spotted them just in time with binoculars. The drone succesfully  flew  over them, but shortly after I lost signal. I got one message  with 'make sure nothing is blocking the atennas', but they were in good  position towards the drone in front of us. After the RC lost connection  the drone went straight back to home-point as it should. I knew it would  be okay, but still a bit scary when you can't control the drone with RC  anymore.


When we were on the way back out of the jungle I wanted to make one last shot. Turns out it was also the last..

I  set the MA up on the ground, waiting for signal and the recording for  the home-point. It was a bit difficult to get enough signal, so I walked  to a few different places on the road to get the best signal. After 5  minutes or so, I was still hovering above the road.  Then a message with  'maximum altitude reached' grabbed my attention. I went through all the  settings, beginners mode was disabled, compass is callibrated  everything seamed fine. Landed it, booted it up again. There was a  message about the back sensor not working properly, but I flew multiple  times even without the sensors. In open space that wouldn't be a  problem. After a bit hovering above the road it seamed okay,  so I flew  it in the valley. It was strange because sometimes it would go up if I  pushed the RC to go up, and sometimes the message about the maximum  altitude came up again and wouldn't let me fly higher. One time the  message came up and the drone was even lower than were it had started.  It also seamed to drift a bit, only downwards though.

Also  there was this message about the backsensor not working properly. I let  it hover, changed some lighting settings and flew a bit. Then there was  some glitching, a message about aircraft interference, and then I again  couln't control the aircraft anymore. It didn't seam to react on the  movements I was making on the joysticks.

This all  happened not far from the road in open air between two mountains in the  valley. Lots of space to fly. But I was creeped out by this weird  altitude behaviour, so I tried Return Home. Which it of course didn't  do, because I forgot about that in the beginning.

After  minutes running up and down the road, the drone was not that far away  (about 100 meters from the road, and maybe 300 from starting point I  think) but unretrievable because of the forest. The RC was still beeping  from trying to return home, but nothing was happening. Then the message  with 'motor obstructed' said it all.

That was the moment I knew I lost my drone.


Looking  back I know I shouldn't have pushed this last fly, shouldn't let me  rush by others to do it quick, should have followed protocol and waited  for home-point recording and sufficient GPS. This is a major fault, but  I'm not giving up droning. Definitely not letting one error get in the  way of my hobby. It's a pity it will cost me maybe a year to get the  savings to buy a new one.

So, if anyone could help me learn from this event, I would be thankful!


Questions:
  • Why  did the drone lose control the first time? It was in front of me, the  antennas were directed at it. Do the wires have anything to do with it?
  • In  my flight logs I have a few flights which are labeled 'No GPS',  including the report of the last one. Other reports do have signal,  flight paths rendered, home-point recorded and all. Why is it labeled as  No GPS?
  • What was wrong with the back sensor? What could  have caused this messages to appear when there was nothing near the  aircraft? And in the end, it maybe did hit something and it obstructed  one of the motors?
  • Why was it saying 'Maximum altitude reached' when it was hovering a few meters above the ground?
  • Why was it drifting downwards? Is this because of the sensor, or the signal being too weak?


I wil provide 3 flightlogs:
A= Normal good flight
B= First flight with lost control
C= Final crash


A= https://www.phantomhelp.com/LogViewer/U697R0HSPI3WQP2JBFQB/

B= https://www.phantomhelp.com/LogViewer/TDKPP6SAOPEEOWD19L1T/

C= https://www.phantomhelp.com/LogViewer/VYISRSQEQABIQHA5B7ZW/

I really hope someone with more experience could shed a light on this.

Thanks in advance!


2019-5-7
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LilyValley
lvl.2
Flight distance : 141220 ft
Netherlands
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2019-5-7
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DJI Gamora
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Hi, LilyValley. We do apologize for the incident happened to your DJI Mavic Air. I would recommend you contact our support team to start up a ticket: https://www.dji.com/support. We have the professional team who would do their best to find out the reason for the incident and then the corresponding resolution would be provided. Please note that DJI will not perform data analysis for cases occurring after the expiry of the warranty period; otherwise, valid charges will apply. Thank you for your understanding. Best Regards!
2019-5-7
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LilyValley
lvl.2
Flight distance : 141220 ft
Netherlands
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DJI Gamora Posted at 5-7 12:59
Hi, LilyValley. We do apologize for the incident happened to your DJI Mavic Air. I would recommend you contact our support team to start up a ticket: https://www.dji.com/support. We have the professional team who would do their best to find out the reason for the incident and then the corresponding resolution would be provided. Please note that DJI will not perform data analysis for cases occurring after the expiry of the warranty period; otherwise, valid charges will apply. Thank you for your understanding. Best Regards!

Okay, even if I forgot to wait for the home-point to be recorded? I will look into it tomorrow, and you're right of course I can always try.
2019-5-7
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PS013
First Officer
Flight distance : 3579409 ft
United States
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I will try to answer your questions, and I am sure that others can add alot to this.

Why  did the drone lose control the first time? It was in front of me, the  antennas were directed at it. Do the wires have anything to do with it?
Yes, it is possible that the magnetic field of the power lines could have disturbed the communication

In  my flight logs I have a few flights which are labeled 'No GPS',  including the report of the last one. Other reports do have signal,  flight paths rendered, home-point recorded and all. Why is it labeled as  No GPS?
If the GPS signal is weak, the craft will have an 'unprecise' positon - good enough for mapping, but not enough for hovering or RTH.

What was wrong with the back sensor? What could  have caused this messages to appear when there was nothing near the  aircraft? And in the end, it maybe did hit something and it obstructed  one of the motors?
You will see messages stating that the back sensor is disabled when the craft is angled. This is normal and can happen at high speed or in high wind.
You will also see messages when the rear sensor is too close of something or it is too dark ( insect, dirt, moisture on the sensor ? )

Why was it saying 'Maximum altitude reached' when it was hovering a few meters above the ground?
When the GPS signal is weak, the max altitude when downward vision is enabled is 5 meter ( see page 48 of the manual below )

You took off with no or weak GPS signal, of course with no home point recorded ... I am affraid that the accident was almost garanteed.

Also, if may want to look at some of these posts https://www.google.com/search?q=dji+mavic+how+many+satellites






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2019-5-7
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AntDX316
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When I had my backwards sensor go off midair while flying, when I had obstacle avoidance "errors" while flying, looking up I see birds around it trying to hit it out of the sky lmao

I assume this is what happened to yours.  Seeing motor obstructed is another reason that validates my theory considering you didn't fly into a tree limb.

Also how come home distance says 0 ft?  Also the other idea is to readjust the maximum RTH altitude when you know the tallest obstacle that could be a hazard is taller than your RTH height value.
2019-5-7
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ro_flyer
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Flight distance : 7557283 ft
Brazil
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I see you had some questions answered and I will give one more tip:  RTFM.   
2019-5-7
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LilyValley
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Flight distance : 141220 ft
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ro_flyer Posted at 5-7 18:43
I see you had some questions answered and I will give one more tip:  RTFM.

Will look into that more thouroughly than only skipping through like I did.. :-)
2019-5-8
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LilyValley
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Flight distance : 141220 ft
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AntDX316 Posted at 5-7 16:22
When I had my backwards sensor go off midair while flying, when I had obstacle avoidance "errors" while flying, looking up I see birds around it trying to hit it out of the sky lmao

I assume this is what happened to yours.  Seeing motor obstructed is another reason that validates my theory considering you didn't fly into a tree limb.

There were no birds visible, my spotter didn't see any. Insects could be the problem maybe.
Home distance is zero because I was distracted with the altitude problems, and didn't wait for the home-point to be recorded. Stupid I know..
2019-5-8
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LilyValley
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PS013 Posted at 5-7 13:59
I will try to answer your questions, and I am sure that others can add alot to this.

Why  did the drone lose control the first time? It was in front of me, the  antennas were directed at it. Do the wires have anything to do with it?

Thanks for the answers!

So, the overall weak GPS signal caused the drifting and the maximum altitude reached problem.  Shouldn't there be a message about weak signal then?
I thought the drone would go in ATTI mode when there is no sufficient GPS. That never happened.

But the message saying the backsensor not working properly still keeps me thinking. It was clean for take-off, not speeding, most of the time even hovering in the valley because of the maximum altitude reached message which I was struggeling with.
If the forward and backward Vision system didn't work, also should be automatically turn to ATTI mode.

Did you ever experience weird behaviour with your drone while flying in a valley between mountains?  
2019-5-8
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PS013
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LilyValley Posted at 5-8 05:08
Thanks for the answers!

So, the overall weak GPS signal caused the drifting and the maximum altitude reached problem.  Shouldn't there be a message about weak signal then?

True, with the low number of satellites in the log, I would have expected to see the craft in ATTI mode, and not P-GPS ….

Regarding the back sensor, I could not add more than what is in the log, the rest is mostly speculation as I have no idea of the environment you were in,

Finally, I have very little experience with mountainous terrain as I am in the greater Chicago area, and the landscape is a flat as what you have in the Netherlands
2019-5-8
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LilyValley
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Flight distance : 141220 ft
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PS013 Posted at 5-8 05:42
True, with the low number of satellites in the log, I would have expected to see the craft in ATTI mode, and not P-GPS ….

Regarding the back sensor, I could not add more than what is in the log, the rest is mostly speculation as I have no idea of the environment you were in,

Jup, zo plat als 'n dubbeltje we like to say here :-) As flat as a coin.

Thanks anyway!
2019-5-8
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AntDX316
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LilyValley Posted at 5-8 02:36
There were no birds visible, my spotter didn't see any. Insects could be the problem maybe.
Home distance is zero because I was distracted with the altitude problems, and didn't wait for the home-point to be recorded. Stupid I know..

Waiting for GPS lock is important though.  If you take off in Atti it won't GPS lock at all until you land and get a signal lock?

Maybe the GPS in that region is very bad.

At the moment of motor overload, did your spotter have eyes on the aircraft all the way to it crashing or before that time?  It didn't matter about all the times you guys were watching if that time a bird came in and hit the propeller.
Some birds come fast.
2019-5-8
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