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Lost my Mini in the woods - could someone look at the log?

Hutch1080

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So, after a year I have now lost my drone to the forest... I've pretty much come to the conclusion that I was too low for the terrain I was in (forest full of tall trees).
Nevertheless, could someone (possibly) give me some more info on what went wrong? What confuses me is that I was never able to use the "beep/flash" option to possibly retrieve it.
The last I saw was the tumble of death and that was it.
Appreciate any bit of extra info I could get!

THANK YOU!
 

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  • DJIFlightRecord_2021-07-26_[20-23-12].txt
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... I've pretty much come to the conclusion that I was too low for the terrain I was in (forest full of tall trees).
Nevertheless, could someone (possibly) give me some more info on what went wrong? What confuses me is that I was never able to use the "beep/flash" option to possibly retrieve it.
This incident is pretty straight forward ... it wasn't a crash in a tree as your Mini was up on 57,6m above the HP & the location where this happens is about 18m below your HP (according to GE) ... it would need a tree with a height of 75,6m to stop the Mini.

Here a pic of the trees very near to where your Mini went down ...

1627342211127.png

At 357,7sec into the flight & approx 75m above the ground you releases the elevator stick from full in Sport mode & immediately apply full throttle for descending. Just when the breaking is finalized & the Mini return the pitch to normal flat level it suddenly start to yaw CW, continue to pitch forward down & roll over to the left ... all very typical for a lost thrust in the front left side ... possibly due to a lost prop or a failing motor. The mini then spirals down & the connection is lost with the Mini approx 34m above the ground beneath.

It happens here ...

1627341098313.png

And here is all the relevant data, the marker is placed where the incident starts at 357,7sec (click on the chart to make it larger)

1627341142127.png

That the beep/flash didn't work is probably due to that your RC wasn't connected with the Mini anymore, either you weren't close enough or the battery got dislodged in the crash.
 
Last edited:
This incident is pretty straight forward ... it wasn't a crash in a tree as your Mini was up on 57,6m above the HP & the location where this happens is about 18m below your HP (according to GE) ... it would need a tree with a height of 75,6m to stop the Mini.

Here a pic of the trees very near to where your Mini went down ...

View attachment 132413

At 357,7sec into the flight & approx 75m above the ground you releases the elevator stick from full in Sport mode & immediately apply full throttle for descending. Just when the breaking is finalized & the Mini return the pitch to normal flat level it suddenly start to yaw CW, continue to pitch forward down & roll over to the left ... all very typical for a lost thrust in the front left side ... possibly due to a lost prop or a failing motor. The mini then spirals down & the connection is lost with the Mini approx 34m above the ground beneath.

It happens here ...

View attachment 132411

And here is all the relevant data, the marker is placed where the incident starts at 357,7sec (click on the chart to make it larger)

View attachment 132412

That the beep/flash didn't work is probably due to that your RC wasn't connected with the Mini anymore, either you weren't close enough or the battery got dislodged in the crash.
Amazing analysis! Thank you so much for that! Could this have been avoided or was this a freak accident?
 
Could this have been avoided or was this a freak accident?
**Updated**

You were flying around and 195 ft up in Sport Mode, when at 356.5 seconds you pulled the left stick down hard.
At 358.2 seconds the drone had descended a few metres before it lost a motor and the drone tumbled down.
The data ends with the drone 16 metres higher than the launch point, which would put it at around ground level where it crashed.
 
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...Could this have been avoided or was this a freak accident?
With a proper pre-flight check of the motors for debris inside/dust/roughness and a control of the props for bends, nicks, cracks & properly tightened screws ... can reveal shortcomings before disaster strikes airborne.

You were flying around and 195 ft up ... At 358.2 seconds the drone had descended 12 feet and hit a tree.
That would make 183ft above the HP ... a HP which according to GE is 18m above the location where the incident happens ... no such tall trees exists there, out from the street view pics they are max 30m.

Really doubt that it was a tree hit this time ...
 
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With a proper pre-flight check of the motors for debris inside/dust/roughness and a control of the props for bends, nicks, cracks & properly tightened screws ... can reveal shortcomings before disaster strikes airborne.


That would make 183ft above the HP ... a HP which according to GE is 18m above the location where the incident happens ... no such tall trees exists there, out from the street view pics they are max 30m.

Really doubt that it was a tree hit this time ...
Don't think GE has giant Sequoyah's, do they? Most of the trees I fly around, even in old growth are no more than about 125 ft or so; so if at over 150 ft - then I'd say you are correct on no tree incident.

Think he should contact DJI to file if he has FlyAway / Refresh and see what they say - maybe they'll replace the drone.
 
That would make 183ft above the HP ... a HP which according to GE is 18m above the location where the incident happens ... no such tall trees exists there, out from the street view pics they are max 30m.
Double checked the data and you're correct.
I've updated my post above.
 
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This incident is pretty straight forward ... it wasn't a crash in a tree as your Mini was up on 57,6m above the HP & the location where this happens is about 18m below your HP (according to GE) ... it would need a tree with a height of 75,6m to stop the Mini.

Here a pic of the trees very near to where your Mini went down ...

View attachment 132413

At 357,7sec into the flight & approx 75m above the ground you releases the elevator stick from full in Sport mode & immediately apply full throttle for descending. Just when the breaking is finalized & the Mini return the pitch to normal flat level it suddenly start to yaw CW, continue to pitch forward down & roll over to the left ... all very typical for a lost thrust in the front left side ... possibly due to a lost prop or a failing motor. The mini then spirals down & the connection is lost with the Mini approx 34m above the ground beneath.

It happens here ...

View attachment 132411

And here is all the relevant data, the marker is placed where the incident starts at 357,7sec (click on the chart to make it larger)

View attachment 132412

That the beep/flash didn't work is probably due to that your RC wasn't connected with the Mini anymore, either you weren't close enough or the battery got dislodged in the crash.
What software did you use to generate the graph?
 
With a proper pre-flight check of the motors for debris inside/dust/roughness and a control of the props for bends, nicks, cracks & properly tightened screws ... can reveal shortcomings before disaster strikes airborne.


That would make 183ft above the HP ... a HP which according to GE is 18m above the location where the incident happens ... no such tall trees exists there, out from the street view pics they are max 30m.

Really doubt that it was a tree hit this time ...
Thanks for the analysis. My Mini is/was about a year old and hasn't seen crazy flight time yet. A few minutes here and there is all I have done so far. I can pretty much rule out any nicks or bends. I remember an incident from one of my last flights though where it spiraled for a second or two but then continued its flight with no further issues. I'll check my logs if I can find that incident.

* Attached is the log. Side shock was detected. I know the area (unlike my current one) well, and there is no obstacle that could've caused an impact.
 

Attachments

  • DJIFlightRecord_2021-04-12_[16-29-56].txt
    1.1 MB · Views: 8
Last edited:
**Updated**

You were flying around and 195 ft up in Sport Mode, when at 356.5 seconds you pulled the left stick down hard.
At 358.2 seconds the drone had descended a few metres before it lost a motor and the drone tumbled down.
The data ends with the drone 16 metres higher than the launch point, which would put it at around ground level where it crashed.
You're saying ground level? So my search should focus more on the ground? Not that I have much hope of finding anything...
 
...I remember an incident from one of my last flights though where it spiraled for a second or two but then continued its flight with no further issues.
Yep ... nearly a copy in this older flight as in your recent incident where your Mini went down. Again a rapid release of the elevator stick from full forward in Sport mode ... but this time you didn't apply any throttle for descend. Your Mini pitches heavily nose up for breaking & then dives nose down with 41 degrees (more than spec), rolls over hard to the left with 86 degrees & spin nearly a full turn CW. All again points to a lost thrust in the left front.

It happens here ...
1627419581707.png


(Click on the chart to make it larger)
1627419353322.png

This really points to a motor problem ... if you can provide the mobile device .DAT log from any of these 2 flights it will probably be easy to determine if it's a motor or a prop that causes this. The .DAT logs is in the mobile device you flew with in a sub folder "MCDatFlightRecords"where the .TXT logs are ... the 2 .DAT logs of interest ends with FLY071.DAT for the older flight & FLY073.DAT for the crash flight.
 
You're saying ground level? So my search should focus more on the ground? Not that I have much hope of finding anything...
No ... that estimation mentioned is wrong.

First ... the ground at the crash location had a elevation of 333m. At your launch point (the HP) the elevation was 350m, see the pic below from GE.

1627421866452.png

When you lost the connection with your Mini the .TXT log indicate that the Mini was on 16,3m above your HP & had a heading speed of 3,5m/s.

1627422525001.png

That means that when you lost the connection & the log ends the Mini was still above the trees ... 350m-333m=17m in elevation difference (crash location lower than the HP). These 17m + the height from the log of 16,3m = 33,3m above the ground below travelling with 3,5m/s.

But the Mini will be somewhere very near the last location from the log (Lat 48,6185 Lon 6,983) as it would have hit the trees & either tumbled down to the ground or got stuck up there.
 
Another reason to thread lock every time you remove or replace the prop.
But being careful not to use a normal (anaerobic) thread lock as these can cause the plastic to become brittle.
 
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