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Mavic 2 Pro forced to auto-land in wetland after extended flight in same airspace by Litchi

PacificTrade

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Hello pilot community. I am trying to understand what happened during a recent, potentially dangerous incident. These are the facts:

- I initiated a flight in Litchi and completed two autonomous orbits without any issues or warnings
- while in the air, I switched to DJI GO 4 to do some additional photo work
- within a few seconds, a message flashed, indicating auto landing (this was NOT a restricted airspace)
- I switched to sport mode and tried to bail out of the forest but within a few seconds I was between tall trees so I let go of the controls and I lost connection

The area was a forested patch of wetland. Fortunately, the drone landed in a rough blueberry bush instead of the water nearby and survived, but the incident could have gone much worse if this happened over water, over private property, busy urban area etc.

After the incident, at a different location, I was about to test the drone but DJI GO 4 would block the drone from taking off, claiming a no-fly zone. I suspect that the bogus message may have been triggered by the fact that a DJI zone unlock was left ON accidentally in the controller from the previous day. Once the zone unlock (for a far away location) was turned OFF, the drone took off.

So, has anyone experienced a similar auto-land scenario, after an extended autonomous flight, which I assume would use the DJI engine under any third party UI, like Litchi, in this case? How did Litchi fly the drone for almost ten minutes but then GO 4 pushed it down into the swamp when I switched over? Why doesn't normal airspace cancel/override a selected but irrelevant or far away unlock zone ... if, that was the root cause of the forced, unsafe action. Why didn't GO 4 create a log record for the auto-landing incident? Litchi recorded the two orbits, but there is no log record of the actual incident just a screenshot of the moment when the drone disconnected. And perhaps most importantly, why can't we have an abort switch for forced landings? Often the "solution" to imaginary problems is worse than no action. This was at least the third forced landing that I recall in the past year and one of these could turn uglier in the future. In none of those three cases was the drone actually in a no-fly zone. What is the justification for not having at least a hover above ground option?
 
What was the actual battery cell voltages during all these auto landings... & were you using the same battery in all 3 landings?

And no logs created in your mobile device where they usually are stored?
 
Moments before I switched over to DJI GO 4, Litchi recorded:
63%15.438V3.87V3.87V3.86V3.84V0.033V

The earlier incidents happened months ago and batteries have not been suspect then or now. One of the earlier landings likely happened because of the often inaccurate DJI map. I was on the border of an imaginary no-fly zone due to the sloppy DJI boundaries. No airports nearby and I didn't check before takeoff. The drone went up and soon came down over a fenced private property. I barely managed to nudge it over the fence while landing.
 
If I understand you correctly, full or substantial throttle can keep the drone in the air for a while during "forced landing" but not indefinitely, maybe long enough to get the drone to safety. Horizontal control may be wooly.
 
I don't know from these things yet, but you switched apps while your drone was in flight?
Is this normal protocol?
It's not something that many fliers would do, but there's no reason that it should cause any problems.
You close one app and the drone hovers waiting till you start a new app and resume flying.
 
...Why didn't GO 4 create a log record for the auto-landing incident?

But have you checked your mobile device for the GO4 .TXT logs... or have you done that already or did you conclude that they were missing in some other way?

The logs are located:

iOS:
Apps » DJI GO 4 » FlightRecords

Android:
DJI » dji.go.v4 » FlightRecord
 
Hello pilot community. I am trying to understand what happened during a recent, potentially dangerous incident. These are the facts:

- I initiated a flight in Litchi and completed two autonomous orbits without any issues or warnings
- while in the air, I switched to DJI GO 4 to do some additional photo work
- within a few seconds, a message flashed, indicating auto landing (this was NOT a restricted airspace)
- I switched to sport mode and tried to bail out of the forest but within a few seconds I was between tall trees so I let go of the controls and I lost connection

The area was a forested patch of wetland. Fortunately, the drone landed in a rough blueberry bush instead of the water nearby and survived, but the incident could have gone much worse if this happened over water, over private property, busy urban area etc.

After the incident, at a different location, I was about to test the drone but DJI GO 4 would block the drone from taking off, claiming a no-fly zone. I suspect that the bogus message may have been triggered by the fact that a DJI zone unlock was left ON accidentally in the controller from the previous day. Once the zone unlock (for a far away location) was turned OFF, the drone took off.

So, has anyone experienced a similar auto-land scenario, after an extended autonomous flight, which I assume would use the DJI engine under any third party UI, like Litchi, in this case? How did Litchi fly the drone for almost ten minutes but then GO 4 pushed it down into the swamp when I switched over? Why doesn't normal airspace cancel/override a selected but irrelevant or far away unlock zone ... if, that was the root cause of the forced, unsafe action. Why didn't GO 4 create a log record for the auto-landing incident? Litchi recorded the two orbits, but there is no log record of the actual incident just a screenshot of the moment when the drone disconnected. And perhaps most importantly, why can't we have an abort switch for forced landings? Often the "solution" to imaginary problems is worse than no action. This was at least the third forced landing that I recall in the past year and one of these could turn uglier in the future. In none of those three cases was the drone actually in a no-fly zone. What is the justification for not having at least a hover above ground option?
I have switched between Litchi and DJI Go4 dozens of times with no issues. ALWAYS force close one before opening the other. That may improve your results, hopefully.
 
the Litchi manual is quite clear about stopping all DJI running software before launching Litchi to control the flight. I’m not sure what happens if you just fire up the DJI controlling software while leaving Litchi running in background. With my SC I start DJI To select the M2P or Air2S then actively kill Running DJI and only then Launch Litchi. Litchi does not want DJI running not sure if the reverse is true. I’ll follow to see if this helpful or not. Thanks
 
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Personally, I would not dream of disabling Litchi and switching over to DJIGo during a flight. Then again I never use DJI Go for flights at all since I regard it as a decidedly inferior product when it comes to auto flight.
 
I’m not sure what happens if you just fire up the DJI controlling software while leaving Litchi running in background.
My theory: The device Operating System has to assign control of the USB port to an app such as Litchi or Go4. If one or the other has control and continues to run in the background, the results of starting another flight app varies depending on device, OS, and version... sometimes requiring 'force killing' the first app, other times not.
 
Moments before I switched over to DJI GO 4, Litchi recorded:
63%15.438V3.87V3.87V3.86V3.84V0.033V

The earlier incidents happened months ago and batteries have not been suspect then or now. One of the earlier landings likely happened because of the often inaccurate DJI map. I was on the border of an imaginary no-fly zone due to the sloppy DJI boundaries. No airports nearby and I didn't check before takeoff. The drone went up and soon came down over a fenced private property. I barely managed to nudge it over the fence while landing.
On your point of inaccurate maps. I had a mini flying a litchi mission shoot off north at an unprecedented speed, through 2 sets of trees and land 300metres away right in front of a walker. All the button pushing in the world couldnt stop it. All because my galaxy tab device was wifi only and updated whilst at home. That same day, when I tied the galaxy to my phone "out in the field", the map "jumped" about 100 metres south as did the mission start point, 100 metres away from the trees.

The drone was wrecked, the Tab (brand new that week) was returned and swapped for a cellular ipad mini with auto correct compass, and Litchi wäs regrefully consigned to the "not sure about this folder". DJI replaced the drone under care refresh but pointed out that third party apps should not be used and are not certified to run correctly even if developed from the SDK. I like and own Litchi, dronelink, maven etc but am cagey about using these days.
 
On your point of inaccurate maps. I had a mini flying a litchi mission shoot off north at an unprecedented speed, through 2 sets of trees and land 300metres away right in front of a walker. All the button pushing in the world couldnt stop it. All because my galaxy tab device was wifi only and updated whilst at home. That same day, when I tied the galaxy to my phone "out in the field", the map "jumped" about 100 metres south as did the mission start point, 100 metres away from the trees.

The drone was wrecked, the Tab (brand new that week) was returned and swapped for a cellular ipad mini with auto correct compass, and Litchi wäs regretfully consigned to the "not sure about this folder".
I doubt that the incident had anything to do with the tablet or Litchi.
The waypoints are Lat/Long points and the map is just a convenient display, rather than actually controlling where the drone flies.
The tablet doesn't control the drone either.

The incident sounds a lot like a yaw error, which would explain the failure to respond to any controls.
If it was flying a Litchi mission (even one that was wrongly programmed), it would have responded to appropriate control inputs.

 
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