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Did it Crash land or Auto-Land

Sminagos

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Dec 30, 2020
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Age
45
Location
Australia
Hi all,

New to the forums (found by googling related things to the events that occurred today) - sorry for the long-winded post!

Well, today (like other days I decided to fly the mini) was low wind, nice sunny day.

I decided to take off from a coastal town lookout, the lookout was higher than the surrounding area, so I knew I was free of obstacles. The lookout was probably around 1-2kms from the coast so I flew from there and started to record video of the beach etc. Wasn't long before I started to get wind warnings at around 100-120m high - which was a bit odd as I felt nothing and trees in the area were completely still. I know that it's always windier at altitude, anyway decided to start flying back, and that's when things got weird.

I lowered the altitude to perhaps 50-70m to reduce the wind warnings and it didn't seem to make any difference. Lowered the altitude again, knowing that even at 0m I'd still be higher than everything at the relative level. Technically I lost sight of the drone (because of my eyesight really and facing the sun). It would easily have been in line of sight if I had looked hard enough. Yet, I was starting to get connection issues and the video feed would drop off and on. I was still connected and looking at the map I was slowly (very slowly) making progress on returning home. Then things got even weirder, the connection issues were worse where eventually it would disconnect completely (while I am maybe 1k away and very likely to have a line of sight). Of course this initiated a RTH, which I decided to let it do it's thing, but noticed when it got back it's connection and video feed, it was getting further away. I thought maybe the wind picked up and was far too strong for the drone.

Meanwhile, battery was now under 10 mins remaining, and I thought I would override the RTH and put it in sports mode, reduce altitude, and using the map fly as fast as I can towards me. I then had signal and video feed, yet it didn't seem to be moving in my direction. The speed of the drone as recorded on the screen was a negative number as in -3m/s etc. Does this mean the headwind was stronger than the Mavic's sports mode speed? That's how I interpret it.

Now the time remaining was quite low, I thought right there that my best chance of retrieving the drone was to land it in a suitable location where I could drive to pick it up. I turned the camera down and picked a spot and continuously held the down stick, meanwhile losing the connection to the video and eventually the controller. It was probably still 50m above actual ground level before losing signal completely. I had no idea what happened after that and the only information I had after that point was the 'last known coordinates'. I immediately drove the location, jumped a barbed wired fence onto a rural property, and searched the area thoroughly for about half an hour. I couldn't connect to the controller while I was in that area, so I assumed it was crashed and dead, or dead battery not sure.

After searching thoroughly, I decided it was history and jumped in the car to leave.

Almost an hour later when I was nearly home, my phone rang when a nearby resident found the drone in his yard (about 250m from last known coordinates). He said it looked ok, nothing seemed to look broken. He sent me a picture and sure enough, it looked like it landed ok. I returned to pick it up and sure enough, it doesn't appear to be damaged at all.

I replaced the battery with a spare that I had and it connected to the controller and iPad as per normal, with no errors on startup other than a compass calibration requirement. Tomorrow I will attempt to fly it (cautiously, in the park to test all the functions out again).

My main question is - did this thing land itself? or did it survive a crash (i.e how robust is it?) The actual ground level in that location is probably 100m lower than it's take-off location, how does the Mavic mini know it's close enough to the ground to land itself?

The actual events may not be precisely described as I was in panic mode, but it will be somewhat accurate!
 
Last edited:
Yeah ... try to post the mobile device TXT log here ... read up here on how to retrieve --> Mavic Flight Log Retrieval and Analysis Guide (read under section 3.), then either attach it directly in a new post here or share a link to the suggested PhantomHelp link above.

From your description it sounds like a case with a possible pitch angle way lower than spec. due to deformed props in the rear ... that could explain the wind warnings, the bad heading speed in Sport mode & that commanding RTH fails to bring it in (if it actually was low winds)... but the log will tell.

When you tried to land & lost connection ... the Mini would have initiated the failsafe action, which usually is RTH. So it would have ascended up to RTH height again & continued to drift away eventually hitting low battery auto landing.
 
When descending, it just keeps on going down until the bottom sensors visually and with IR detect that it is within 2 ft of ground. It pauses, then actually lands. When attempting to descend no longer achieves any change in altitude, it assumes it's on the ground and cuts off motors.
 
It likely landed when out of battery, but not before trying another RTH.

I turned the camera down and picked a spot and continuously held the down stick, meanwhile losing the connection to the video and eventually the controller.
When doing that you should first change the RTH settings to land in place, otherwise when you almost certainly lose connection as you're trying to land it far away it'll climb and try to come back to you again. Guess you were "saved" by the low battery condition meaning it gave up on that and landed close enough to where you intended.
 
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Can you post the flight log in the phone and upload to PhantomHelp at DJI Flight Log Viewer | Phantom Help ? instructions are given at the bottom of that webpage
Hi there,

Are there logs on the mavic mini itself? What would the iPad logs offer that I don't already know (I am a little confused by that).

I see the only way to extract it from the iPad is with iTunes - which I am having an issue at the moment trying to install. The only PC access I have is a work pc and iTunes is blocked from some reason.
 
It likely landed when out of battery, but not before trying another RTH.


When doing that you should first change the RTH settings to land in place, otherwise when you almost certainly lose connection as you're trying to land it far away it'll climb and try to come back to you again. Guess you were "saved" by the low battery condition meaning it gave up on that and landed close enough to where you intended.
Thanks for that, I will definitely keep this in mind!!
 
Hi there,

Are there logs on the mavic mini itself? What would the iPad logs offer that I don't already know (I am a little confused by that).

I see the only way to extract it from the iPad is with iTunes - which I am having an issue at the moment trying to install. The only PC access I have is a work pc and iTunes is blocked from some reason.
Yes, you will need iTunes to extract the flight log files in the ipad.
 
Can't give a technical analysis but I can feel your joy and relief when that phone rang and the person on the other end said that the Mini was found.

Glad you got it back. Thumbswayup :)
 
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Can't give a technical analysis but I can feel your joy and relief when that phone rang and the person on the other end said that the Mini was found.

Glad you got it back. Thumbswayup :)
You have no idea lol. I took it out this morning for the first time since and was nervous as hell - but all went perfect and performed as expected!!
 
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...What would the iPad logs offer that I don't already know (I am a little confused by that).

Well, you put up some specific questions in your first post ...

"My main question is - did this thing land itself? or did it survive a crash (i.e how robust is it?) The actual ground level in that location is probably 100m lower than it's take-off location, how does the Mavic mini know it's close enough to the ground to land itself?"

don't you want the answers to those anymore? All you know for sure so far is that you lost your Mini & it was found & returned to you ... the rest is only well founded speculations.
 
Sounds to me that you might want to figure out how to retrieve you files and let the experts let you know what is going on.
 
Well, you put up some specific questions in your first post ...

"My main question is - did this thing land itself? or did it survive a crash (i.e how robust is it?) The actual ground level in that location is probably 100m lower than it's take-off location, how does the Mavic mini know it's close enough to the ground to land itself?"

don't you want the answers to those anymore? All you know for sure so far is that you lost your Mini & it was found & returned to you ... the rest is only well founded speculations.
of course I do - but how would this information be on the iPad if I lost connectivity before these events?
 
of course I do - but how would this information be on the iPad if I lost connectivity before these events?
Hello Sminagos:

Welcome to the forum & congratulations on getting your drone back - that’s a great story.

The flight logs that others are suggesting you download and post include a lot of details of what instructions the drone was following during the flight - both how it interpreted “commands” from you as well as “automatic” flight control settings it might have been responding to. Some of the folks here are real wizards at pulling environmental conditions from those logs, etc. In many cases the logs contain records from longer periods that we’d expect based on our interpretations of what we saw on the screen.

As you suggest, those logs might not further your understanding of “what“ happened, but they could be crucial in understanding “why” that happened.

Howard
 
Hello Sminagos:

Welcome to the forum & congratulations on getting your drone back - that’s a great story.

The flight logs that others are suggesting you download and post include a lot of details of what instructions the drone was following during the flight - both how it interpreted “commands” from you as well as “automatic” flight control settings it might have been responding to. Some of the folks here are real wizards at pulling environmental conditions from those logs, etc. In many cases the logs contain records from longer periods that we’d expect based on our interpretations of what we saw on the screen.

As you suggest, those logs might not further your understanding of “what“ happened, but they could be crucial in understanding “why” that happened.

Howard

Hi there.
What I would like to know is how did that guy know who to ring, your name and phone number?

Cheers Janset
 
of course I do - but how would this information be on the iPad if I lost connectivity before these events?

They'll show what was happening *until* you lost connectivity. Which would let the experts explain what happened.

Without that analysis you risk repeating the mistakes or malfunctions of the past.

Lastly, reading your post I'm not entirely clear what the maximum distance was, but if I understand you correctly it was at least 1km and perhaps up to 2kms? As any glider pilot or sailor will tell you, that is *easily* enough distance for there to be significant changes in wind strength and direction in a coastal area. In some cases extreme changes.

But anyway, your choices are :). ......

1. Logs and expert analysis ??
or
2. Prayer and guesswork ?

Also, cheers from a fellow drone operator in Australia.
 
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