I need help locating my Mavic 2

[mz-in-cali]

I lost my Mavic earlier. I was flying it and I lost contact as it started to go behind a hill. I moved to get into a better spot since I had flown there coulntless times, but I could not make contact again. I was in Sports mode, so maybe it continued i's path for too long and fast before and after the signal was lost. I drove to the area where I last observed on the video. I made contact with it. It looked like it was under a tree, and the message on the screen was that it could not lift-off because it was not level. It was getting dark, so I turned on the location flash and sounds. I did not hear anything or see anything. I tried to locate it on the map, but it didn't seem to know where it was. The remote said that it had GPS, and I had good signal. I moved around to see if my signal level would increase or decrease, but I got inconsistent results. Sometimes walking in a direction would make the signal level rise, other times, the same spot would have differnt results. I tried staying in one spot, rotating to see if the antenna position could help me out. No luck. My last attempt was to download the last video so that I could see where it was before it ended up under the tree. The flight video on my phone stops when the signal stopped. The video file must be husge. I started downloading it and even though I still had about 20% charge on the drone when I started, it did not complete before the drone ran out of juice. By then it was dark too, so I would have seen the flashes if the Mavic was close by. I am now trying to get the logs and any partial video files off the phone, although the one that was being downloaded from the drone while the battery ran out, is probably in a /tmp directory and is unavailable to me. Not sure what I can do. Oh, I also checked the Find My Drone area of the app. It shows the drone in the same spot that I lost signal. I was walking around that spot, or very close, but did not see nor hear it. That area is very hilly and there's lots of poison oak, so I couldn't stay out there and keep walking around in the dark. I am hoping I can get some better ideas of where to look before I go back tomorrow. Can anyone tell me where I can find the tools to read the log files? I am hoping that while I was connected to the Drone before the power went out, and it was still downloading the video, that it might have sent some information, like the GPS location before it went under the tree, or how far it tried to go to RTH or not, after the signal was lost. I am very surprised that RTH did not bring it back to me. But I have had it behave oddly when in sports mode when signal goes out and comes back and it seems to not know whether to continue RTH or Sports mode. RTH with Sports mode might be problematic too since the obstacle detection doesn't work or work as well in Sports mode? I am enclosing the screenshot of the Find My Drone screen. Is that location supposed to be where the drone was last reporting after the disappearance, or merely where my phone last had contact in-flight? Because that is where I was and could not see or hear it. I was assuming that maybe that was just where it last communicated before going down. Why it wouldn't update after when I had video signal, is beyond me. Thank you! -mz

 

[AMann]

Hope this helps, sounds like you may have a good chance of recovering it from a good GPS fix. Good luck!

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[Meta4]

Can anyone tell me where I can find the tools to read the log files?

Go to DJI Flight Log Viewer | Phantom Help
Follow the instructions there to upload your flight record from your phone or tablet.
That will give you a detailed report on the flight data.
Come back and post a link to the report it gives you.

 

[mz-in-cali]

Hello!! I found my drone. Wasn't easy. It was under a bunch of oaks and bay trees, on the ground. It was a miracle it made it through the canopy. To find it, I watched the video cache from the DJI Go4 app, and extrapolated the last little hook to the right, and searched there instead of where the "Find My Drone" told me to look. It was a good 200 yards away, and 50 ft or so uphill. I actually looked until it was dark and then used a flashlight hoping to get a glint of something different than organics (It was a bit Blair Witchy out there, with no people nearby, and much rustling in the bushes).



I’m surprised that the Find My Drone screen didn't update its location once I was nearby the night before, before the battery ran out.



I'm sure you are dying to know: nothing was broken but 3 props that were dinged and one that was completely missing. Lucky that I found it and lucky that everything is functional and unscathed.



Now to figure out why this happened. I had been going towards the reservoir, but intended to stay on one side of the road, and was going to curve around with the road. When the signal went out, it seems like the drone was just starting a slight turn to the right.



Here is the cache video file from the remote leading up to the crash: (I have the video from the drone now and that is at the end)



lastpartbeforeconnectionloss.mov



Here is my flight record file leading up to the crash. The data seems to stop right where the Remote video cache ends.

(Screenshot of that: lastpartoflog.png )

Dropbox - File Deleted - Simplify your life

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I don't know if these can help, but they are the DJILogxxxx.log files. The last two from before the crash.

Dropbox - Error - Simplify your life

www.dropbox.com

Dropbox - Error - Simplify your life

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Finally the video from the drone:



lastpartfromthedrone.mp4



There’s a lot going on there. Looks like I started to go around the hill and lost at least video signal, so I turned away from the hill. Did I end up doing about a 300 degree turn and face the hill? And then go straight into the hill? My recollection was that I tried to turn away slightly and to climb, but then I let the controls go to allow the signal loss RTH to do its thing. However, it looks like RTH might have tried to descend to RTH altitude? Does it to do that or if RTH altitude is less than current altitude does it stay at that altitude?



Then there’s the spectacular high speed crash, and then the ground. Now, why the heck are the motors still running on the ground?



Now how do I get the flight log from the drone, since the one on the phone ends prematurely? I don’t have a USB-C cable handy right now.



-mz

 

[AMann]

Good sleuthing to find it! I put reflectorized tape on mine to help out with nighttime searches like yours, hope to not have to use it. Not sure about the motors- seems like all crashes do that until they stop completely after a second or two.
Glad you can fly again soon!

 

[Meta4]

I’m surprised that the Find My Drone screen didn't update its location once I was nearby the night before, before the battery ran out.

Find-my-drone can only show the last location where it had contact with the drone.
No contact = no updated location.

Here is my flight record file leading up to the crash. The data seems to stop right where the Remote video cache ends.

Dropbox - File Deleted - Simplify your life

www.dropbox.com

There's something not right about that file.
It doesn't read properly.

However, it looks like RTH might have tried to descend to RTH altitude? Does it to do that or if RTH altitude is less than current altitude does it stay at that altitude?

RTH won't descend to RTH at this end.
If higher than the set RTH altitude, it will come straight towards home.

 

[Dragonfly]

As said RTH will not lower it height if drone is already higher than set height, it will just maintain altitude its at.
It appears in your video that Mavic did everything it was supposed to do. It was heading in a direction horizontal to its homepoint when it lost connection with RC. RTH kicked in and drone rotates anticlockwise 270° to face homepoint then heads off towards home at present height as is higher than set RTH height. But hill side is now in way of drones direct line to homepoint and it runs directly into side of hill with trees, crashing into one of the trees toppling to the ground.

 

[sar104]

There is no mystery here - you simply flew it into the trees, and it lost signal at around the same time because you flew it behind a hill:



The txt log shows almost everything up to the crash - full forwards elevator and the yaw maneuver prior to impact:





You can retrieve the DAT file from the aircraft (FLY056.DAT) but since this is a Mavic 2, only DJI can read it.

 

[mikeyway]

Was he in sport mode or why did the VPS not react ?

 

[AMann]

There is no mystery here - you simply flew it into the trees, and it lost signal at around the same time because you flew it behind a hill:

View attachment 70459

The txt log shows almost everything up to the crash - full forwards elevator and the yaw maneuver prior to impact:

View attachment 70465

View attachment 70466

You can retrieve the DAT file from the aircraft (FLY056.DAT) but since this is a Mavic 2, only DJI can read it.

Tree dive bomber maneuver... classic!

 

[Meta4]

The sensors are not 100% effective and can fail to detect obstacles in some situations.

Was he in sport mode or why did the VPS not react ?

Take your pick:

 

[mz-in-cali]

Hey, I just saw all the other responses. Thank you!!

Good to know that RTH doesn't descend to RTH altitude, but stays at height if height is greater.I didn't see any DAT files on the two volumes that presented on my computer when I hooked up the drone. I saw some video files on the internal SD, and the SD had the same files I had already seen before. Where is the DAT file stored?

I do recall trying to head away from the hill, when I noticed the first sign of signal failure. I thought I also wanted to head out away from the hill, but maybe the turn happened too fast and I didn't see where things were headed.

Could the leaves on the tree confuse the VPS?

 

[mz-in-cali]

Find-my-drone can only show the last location where it had contact with the drone.
No contact = no updated location.

I had contact with the drone after the crash. I went to the area, and could see the video being transmitted from the drone. I could make out a canopy of leaves overhead, more light to one side, which indicated the west since that is where the sun had just set, and it was either on the ground or perched on a leafy branch. When I toggled the sound and flashing light alert, I could see that on the video, but of course, I could;d not hear or see it from below where Find-my-drone had told me it had been.

It would be nice if the remote would get updated data and logs after reinitiating contact, for exactly this situation where you have some momentary contact, and then the battery dies or signal is lost again.

 

[mz-in-cali]

What is the red line? The Home point is not correct. I took off from the highest point on the ridge on the left, at the end of Ridge Lane. (hard to see, but there is a Y in the road above where the home point is. Does the home point just look wrong because of the rotation of the map?
View attachment 70459

 

[mz-in-cali]

Are you all sure that RTH did kick in? On the DJI forums a poster said no.

Also, how quickly after signal loss does the drone:
- stop previous control commands and just hover?
- switch modes?
- start RTH?

 

[Meta4]

I had contact with the drone after the crash. I went to the area, and could see the video being transmitted from the drone. I could make out a canopy of leaves overhead, more light to one side, which indicated the west since that is where the sun had just set, and it was either on the ground or perched on a leafy branch. When I toggled the sound and flashing light alert, I could see that on the video, but of course, I could;d not hear or see it from below where Find-my-drone had told me it had been.

It would be nice if the remote would get updated data and logs after reinitiating contact, for exactly this situation where you have some momentary contact, and then the battery dies or signal is lost again.

To update, the drone would have to have a good GPS signal.
Being upside-down or under tree cover etc would prevent that

 

[mz-in-cali]

To update, the drone would have to have a good GPS signal.
Being upside-down or under tree cover etc would prevent that

While I was trying to locate it, the remote would tell me that it was going between ATTI and GPS modes. The GPS signal level on the remote looked ok too. I bet it didn't have a great GPS signal, given that it would switch to ATTI.

 

[Meta4]

Are you all sure that RTH did kick in?

That's how it's programmed to work and how it will have worked unless you changed the settings (but almost no-one does).
Page 17 of your manual explains how Failsafe RTH works.

https://dl.djicdn.com/downloads/Mavic_2/20190417/Mavic_2_Pro_Zoom_User_Manual_v2.0_en.pdf

It's very important to understand it and test it to understand what it does and how it does it.
If the Home Point was successfully recorded and the compass is functioning normally, Failsafe RTH automatically activates after the remote control signal is lost for more than two seconds.

On the DJI forums a poster said no.

I wouldn't worry about that.
There are very few knowledgeable people over there and lots of misinformation.
The moderators know even less than the members.

 

[sar104]

What is the red line? The Home point is not correct. I took off from the highest point on the ridge on the left, at the end of Ridge Lane. (hard to see, but there is a Y in the road above where the home point is. Does the home point just look wrong because of the rotation of the map?
View attachment 70459

I don't know what you mean by the home point not being correct. It was the recorded home point and the flight data shows the track of the flight starting at that point. The red line connects the home point to the last recorded position of the aircraft. This is the view from above:





And this is the entire flight path:

 

[mz-in-cali]

I hate to tell you that that is absolutely not the home point. The home point is much further up the hill. If you look at the arc of the path above it, where it actually does a slight turn to the east, right over the home point. That's where I took off and headed South. Maybe it took it some time to establish a home point. That's the only thing I can think of.

DJI wrote me this morning and said that there was no RTH. I asked why. I guess it may be that it crashed before RTH could kick in. Sometime between video signal loss and at or right after radio signal loss, it hit the trees.