DroneFlying Posted at 2017-12-3 10:18
I am quite surprised that the Mavic could not power through the wind to get back to you. The motors are capable of powering the Mavic to speeds of 40 mph (personally had mine up 39 mph according to my flight data).

The Mavic doesn't fly at maximum (Sport mode) speed during RTH; it limits itself to the 22 MPH maximum at which the obstacle avoidance sensors can still function.

In my opinion, RTH is only a Failsafe option if it's the only usable choice.

It's safer and helpful to manually return to home, and check the speed, the distance and altitude.

And yes, the RTH limit the speed, unfortunately it's not the first time the wind win against RTH ... and it will not be the last as long as people use the RTH for what it is not.

djiuser_L993ni8 Posted at 2017-12-3 12:32
http://www.phantomhelp.com/LogViewer/RWYSNP6DM7SHMER474FW/

Et voila as they say here in France. Let me know if this doesn't work as a link.

It's the wind well knowned named "Mistral" ...

djiuser_L993ni8 Posted at 2017-12-5 02:48
I am sure I could hire someone with a drone.... I don't know anyone with one, and speak French well but not amazingly well. Would it help if I drew lines on the google maps to outline areas searched in relation to the flight path?
... sorry I haven't already done so, I spent a bit of time working at that but haven't gotten it mastered yet.

No DJI Facebook Groups or Clubs in your area you could ask? I know folks are always willing to help out a fellow in need. Maybe you could find someone who will be happy to fly up and down that area with the camera pointing down. And then upload that HD footage for us to scan. You drone has to be within that flight path. Unless it has been picked up by a farm worker.

djiuser_L993ni8 Posted at 2017-12-4 10:50
ok, here's the update.  I appreciate the eyes on this one for those who make it to the end ...

My wife and I spent about 6 hours carefully searching. We started in this field that Drone Flying Captain https://goo.gl/maps/KRiKUtm7U2J2 posted above (Thanks Drone Captain!). This large field is a new peach orchard, well tended, and we walked each row, nothing. The southern border is the 615 on google maps, the other 3 sides are perfectly rectangular. there was a guy clipping tree branches in one part of the field, he hadn't found it, he'll be in that field the rest of this week and beyond. I don't think he found it and hid to keep, seemed pretty honest. Other than a couple rows he had clipped that morning we walked each row

For your question 2 : the collision avoidance was not efficient because the head of the Mavic was oriented to the home point, and the wind move the Mavic back.

I think the trajectory was still the same until it touchdown/crash.

In case of forced landing (at 10% battery), the Mavic don't try to move anymore, only go down.
it was the wind that continued to move it.

Jumbo333 Posted at 2017-12-5 06:08
For your question 2 : the collision avoidance was not efficient because the head of the Mavic was oriented to the home point, and the wind move the Mavic back.

I think the trajectory was still the same until it touchdown/crash.

When forced landing start, do it try to hold GPS point when landing or land like it is in  atti mode?
That can change the aria a lot.

djiuser_L993ni8 Posted at 2017-12-4 10:50
ok, here's the update.  I appreciate the eyes on this one for those who make it to the end ...

My wife and I spent about 6 hours carefully searching. We started in this field that Drone Flying Captain https://goo.gl/maps/KRiKUtm7U2J2 posted above (Thanks Drone Captain!). This large field is a new peach orchard, well tended, and we walked each row, nothing. The southern border is the 615 on google maps, the other 3 sides are perfectly rectangular. there was a guy clipping tree branches in one part of the field, he hadn't found it, he'll be in that field the rest of this week and beyond. I don't think he found it and hid to keep, seemed pretty honest. Other than a couple rows he had clipped that morning we walked each row

I was really hoping to get to the end of this and find a happy ending... Have you plotted your flight data on a map?

DroneFlying Posted at 2017-12-3 13:02
The last log entry showing 17% power at this location is just where the connection between the Mavic and its remote was finally lost and probably isn't where it landed. As you suspected, with 17% battery left it would have continued to drift in the same direction (heading around 133° by my calculations) a little longer. It was using roughly 1% of its battery every 10 seconds, so with 17% battery it would have drifted a little over a minute longer. It was moving at around 3.6 m/s, so another 70 seconds of that would put it somewhere around here when it started landing. I'd begin looking there and search outwardly from that location.

Good luck and please let us know how this turns out.

Based on the last 3 minutes of drifting, I calculated that plane would have flown about 90 more seconds before reaching 10% power and would have drifted another 725 ft before starting it's descent.


Good work DroneFlying  !!  Looks like we pretty much agree    Good luck OP.

Griffith Posted at 2017-12-5 12:35
Based on the last 3 minutes of drifting, I calculated that plane would have flown about 90 more seconds before reaching 10% power and would have drifted another 725 ft before starting it's descent.

A question - various posters are asking me to get another drone to overfly the area and post the videos. I don`t see how that`s going to help better than walking the ground - some of the terrain is bushy and overgrown with deep leaves or grass - is there something I`m missing? Boots on the ground has to be the best level of search I would say but maybe I don`t know something others do.

Latest update: two days spent searching with my wife, nothing. We have walked about 10-20 apart depending on the terrain combing the field originally identified by Drone Pilot as the likeliest point here https://www.google.com/maps/plac ... 4.3%22E/@42.6460794,2.7224045,1169m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d42.645479!4d2.7206461

Then we did the fields left and right of the flight trajectory, then the field directly underneath the last point of contact, and then extended the search downwind to the field beyond the most likely field of landing id`d above. Still nothing.

I`m going to go and search further downwind.

If I recalculate at maximum of 105 seconds of remaining flight to get to 10 % before going down, and use the last 1 second of mapped flight speed of for the whole 105 seconds at  14 feet per second - that puts the furthest downwind range even further. The last one second is significantly higher speed of drift away than previous episodes so it is possible it went further than expected.

It`s pretty hard work to keep searching and not finding

Thanks for the help and encouragement though

And re-reading the wisdom on the 10 % forced landing part, it seems likely the head of the mavic would have been pointing to home but being blown backwards while heading straight down. Since there are lines of approx 50 ` cypress tress as windbreaks around all these fields I will do a re-search of the tree lines looking for a drone in the trees, especially the tree line at the end of the most likely field. We`d already searched the base but it will probably be hard to see the drone up high if its in the branches, we lose soccer balls in those rows of cypresses at times.

One last question - if the mavic was at 133 feet as last altitude when it started its 10 % battery descent, how fast does it go down? ie feet per seconds altitude loss?

Thanks - the support of the community has been +++

djiuser_L993ni8 Posted at 2017-12-6 02:59
One last question - if the mavic was at 133 feet as last altitude when it started its 10 % battery descent, how fast does it go down? ie feet per seconds altitude loss?

Thanks - the support of the community has been +++

9.8 ft per second.

djiuser_L993ni8 Posted at 2017-12-5 02:48
I am sure I could hire someone with a drone.... I don't know anyone with one, and speak French well but not amazingly well. Would it help if I drew lines on the google maps to outline areas searched in relation to the flight path?
... sorry I haven't already done so, I spent a bit of time working at that but haven't gotten it mastered yet.

Midi Pyrenees here and lots of time on my hands, could do with a short break.

david at welshmavic com

djiuser_L993ni8 Posted at 2017-12-6 02:46
A question - various posters are asking me to get another drone to overfly the area and post the videos. I don`t see how that`s going to help better than walking the ground - some of the terrain is bushy and overgrown with deep leaves or grass - is there something I`m missing? Boots on the ground has to be the best level of search I would say but maybe I don`t know something others do.

Latest update: two days spent searching with my wife, nothing. We have walked about 10-20 apart depending on the terrain combing the field originally identified by Drone Pilot as the likeliest point here https://www.google.com/maps/place/42%C2%B038'43.7%22N+2%C2%B043'14.3%22E/@42.6460794,2.7224045,1169m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d42.645479!4d2.7206461

I was just hoping more eyes on the area would be able to help you . I agree walking around would be the best but it is a vast area and this is taking some effort from you and your wife. If your MP had landed it should be easily visible from a vertical view. Not to worry, hope you find it

Having had a think about everything, we are going to try closely examining the tall windbreaks of cypresses on the two ends of the main field the drone should have landed in. I think it likely at this point that it was blown backwards while descending from 133 feet into one of the 50' rows of cypresses. This will complicate things quite a bit though if true. Feeeck! Will see.

hallmark007 Posted at 2017-12-6 03:05
9.8 ft per second.

The other thing to consider it the possible reduction in wind drift as the drone is dropping. At this point, it's in landing mode so there would not be any movement toward home.  I'm not sure if the Mavic will attempt to maintain it's current position while landing or perhaps drift even faster.  A search drone would definitely be helpful.  Some lost drones have been recovered by talking to neighbors or posting a reward.  Good luck.

Success!

Unexpectedly, I found the drone no more than 50 feet underneath the last point of contact. We had searched the further half of that field, the half closest to the field Drone Captain and others had identified as where the drone should be, but as we had approached the half containing the point of last contact we had looked up in the sky, said ok, at last contact the drone was moving 10 feet per second at 133 feet high with 17 % battery .... there's no way ... ever ... the drone could be right underneath the point of last contact. So we had focused on searching left and right of the further field, and then the field even further downwind beyond that given that 10 feet per second last speed.

But this afternoon I'd looked at the battery deets and noticed the battery consumption reading getting more and more erratic as it went further, and after searching the tree lines in my posting from above - I'd thought they were all cypresses and therefore conifers and feck, what to do if its in the branches I'll never see it - they turned out to be all poplars, with leaves on the ground in drifts a foot deep at the bottom in most spots, if the drone was in there no chance of finding it - I decided to search the half of the field right under the last data point. And there it was in the grass, just as I was saying to myself naah there's no way. I was getting a bit dejected at that point actually. 10 hours of hard searching works on your mind a little bit.  

The funny thing is the file for the footage of the last  minute or so and then the final descent only gets a blank screen with the warning the file is corrupted and is unavailable.

I think the drone flew to Ibiza to party with the lady drones ... its covering its tracks

Thanks gentlemen, the community was great for giving more info and insight and helping me wake up every day focused and positive on a new thesis for where it should be.

So what do you guys think? That the drone was down to 10 % and incorrectly reading 17 % and started to descend there, or ... that it kept flying, the wind dropped, it used up the last 6-7 % making headway back towards home point and then hit 10 % about the same point as the point of last contact at 17 %?

Or that it thought to itself naaah I'm going to Ibiza, I'll be back?

Glad you found it, does it work?

djiuser_L993ni8 Posted at 2017-12-6 10:40
Success!

Unexpectedly, I found the drone no more than 50 feet underneath the last point of contact. We had searched the further half of that field, the half closest to the field Drone Captain and others had identified as where the drone should be, but as we had approached the half containing the point of last contact we had looked up in the sky, said ok, at last contact the drone was moving 10 feet per second at 133 feet high with 17 % battery .... there's no way ... ever ... the drone could be right underneath the point of last contact. So we had focused on searching left and right of the further field, and then the field even further downwind beyond that given that 10 feet per second last speed.

Great result for you. This show us how important the flight log is if we understand it.
Was the Mavic ok?

djiuser_L993ni8 Posted at 2017-12-6 10:40
Success!

Unexpectedly, I found the drone no more than 50 feet underneath the last point of contact. We had searched the further half of that field, the half closest to the field Drone Captain and others had identified as where the drone should be, but as we had approached the half containing the point of last contact we had looked up in the sky, said ok, at last contact the drone was moving 10 feet per second at 133 feet high with 17 % battery .... there's no way ... ever ... the drone could be right underneath the point of last contact. So we had focused on searching left and right of the further field, and then the field even further downwind beyond that given that 10 feet per second last speed.

Great news !

It took off and flew in my kitchen anyway just on the controller, will take it outside tomorrow.

yaaaaaaaaa glad you found it!

djiuser_L993ni8 Posted at 2017-12-6 10:40
Success!

Unexpectedly, I found the drone no more than 50 feet underneath the last point of contact. We had searched the further half of that field, the half closest to the field Drone Captain and others had identified as where the drone should be, but as we had approached the half containing the point of last contact we had looked up in the sky, said ok, at last contact the drone was moving 10 feet per second at 133 feet high with 17 % battery .... there's no way ... ever ... the drone could be right underneath the point of last contact. So we had focused on searching left and right of the further field, and then the field even further downwind beyond that given that 10 feet per second last speed.

Awesome, glad yo found it and glad it is in one piece. Now what am I going to do first thing in the mornings, I can longer refresh this page in anticipation of the next update

Kevin36 Posted at 2017-12-6 22:42
Awesome, glad yo found it and glad it is in one piece. Now what am I going to do first thing in the mornings, I can longer refresh this page in anticipation of the next update

Totally awesome, great news!

djiuser_L993ni8 Posted at 2017-12-6 10:40
Success!

Unexpectedly, I found the drone no more than 50 feet underneath the last point of contact. We had searched the further half of that field, the half closest to the field Drone Captain and others had identified as where the drone should be, but as we had approached the half containing the point of last contact we had looked up in the sky, said ok, at last contact the drone was moving 10 feet per second at 133 feet high with 17 % battery .... there's no way ... ever ... the drone could be right underneath the point of last contact. So we had focused on searching left and right of the further field, and then the field even further downwind beyond that given that 10 feet per second last speed.

Thanks for the update; I'm very glad you were able to locate it.

Since you've recovered it would you be willing to upload the DAT file from the Mavic? That would help me to better understand what occurred after the connection was lost and might help me to better pinpoint where to look for others who may have similar problems in the future.

The instructions for accessing the DAT file are here, and once you've retrieved it you'll need to upload it to DropBox (or a similar service) and provide a link to it in this thread. The correct file will have a date and time that correspond to when the flight occurred and will be hundreds of megabytes in size. If you aren't sure which is the correct one then you can just upload all the DAT files on the aircraft and I'll figure out which is the right one.

yay glad you found it...sounds like the drone had a right party ! haha

Classic of case of he who looks finds, well done.

No photos and vid of the adventure??

Glad you recovered it.

djiuser_L993ni8 Posted at 2017-12-6 10:49
So what do you guys think? That the drone was down to 10 % and incorrectly reading 17 % and started to descend there, or ... that it kept flying, the wind dropped, it used up the last 6-7 % making headway back towards home point and then hit 10 % about the same point as the point of last contact at 17 %?

Or that it thought to itself naaah I'm going to Ibiza, I'll be back?

Really happy you got your drone back :-)

As to what the drone was really doing, you can retrieve the flightlogs from the internal SD card using the DJI Assistant 2 software.

A lot of information here is very important and DJI should be doing more to help clients who for whatever reason crash and burn so to speak.

I believe that the info already is quite intense and a owner needs to get out a bit and search.

Look and you will find because it is there.  Somewhere.

Also in France, if you need help etc, France has this wonderful website called leboncoin.  leboncoin.fr it is free to use, ask for help etc etc... loads of Mavs being sold on there???

Kevin36 Posted at 2017-12-6 22:42
Awesome, glad yo found it and glad it is in one piece. Now what am I going to do first thing in the mornings, I can longer refresh this page in anticipation of the next update

Cheers, I know exactly how you feel :0 although my sense in the mornings was more of feck what to try now ...

fans695e1329 Posted at 2017-12-7 05:44
Really happy you got your drone back :-)

As to what the drone was really doing, you can retrieve the flightlogs from the internal SD card using the DJI Assistant 2 software.

yep, I'm going to figure out how to do that and post - check my latest post because the final location was nowhere near what the battery level and flight stats would have suggested according to the other flight log I uploaded.

So I'm going to put up the detailed flight logs as requested by Drone Captain and other posters. Once i get my masters in information sciences that looked complicated

Today I found a way to view the file that was corrupted yesterday, the video of the final descent.

The video shows something totally different than what the final data record I uploaded here suggests  http://www.phantomhelp.com/LogViewer/RWYSNP6DM7SHMER474FW/#

The video shows the drone slowing down and then dropping to land itself. It lands almost directly underneath the last point logged in the flight record above.

The flight record puts the drone moving at 9.3 miles per hour at 137 feet with 17 % battery at last contact. At that point the 17 % battery reading has not changed for 35 seconds, before which it was 19 %, and before that it was 22 % - in other words, the battery sensors at least were not reading and sending accurate information.  Up until the 22 % reading the battery reading was changing approx every 14-15 seconds, dropping by each percent.

Will post when I get the other flights downloaded and posted on dropbox.

I mean I'll post when I get the detailed flight record for this flight on dropbox ....

Hi did you find it in this area?

Aw man I hope you get a happy resolution.  I've had that sinking feeling before when one of my drones decided to take off on permanent vacation.  This is getting really good...what a great community to get in behind this to try and help you out...all the best....and maybe some more wine

RogueDNA Posted at 2017-12-7 10:45
Aw man I hope you get a happy resolution.  I've had that sinking feeling before when one of my drones decided to take off on permanent vacation.  This is getting really good...what a great community to get in behind this to try and help you out...all the best....and maybe some more wine

He found it.

djiuser_L993ni8 Posted at 2017-12-7 10:27
I mean I'll post when I get the detailed flight record for this flight on dropbox  ....

Can you also confirm that Critical Battery Warning was set to 10% not something else.
If it was set to 10% the battery reading seam to bee no to precise.

Very glad that you find your drone!

Was reading this post and I am happy that you could find it!

Welsh Mavic Posted at 2017-12-7 10:53
He found it.

Brilliant thanks WM