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Help! Lost Mavic Air signal during Litchi Waypoint Mission, not seen again since! :(

DaJuice

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Hello brilliant people.

Today I tried to use the Litchi App for the second time on my life. Guess what? after about a minute signal was lost and drone never returned home.
I live on a small mountain and the waypoints are marked where terrain is ascending - see images 1+3 below. Also, I defined the finish action as 'reverse' so I assume it would simply follow the very same mission only in reverse. So I followed the entire mission path and found nothing on the ground. What I also found however is some tall trees that I was dumb enough not to look out for when planning the mission on my Android Tablet.

Any thoughts on where the drone is likely to be along this mission path? all the documents pertaining to this mission are on my Google Drive folder:
Litchi Mission - Lost - Google Drive

Further, 'Find my drone' supposedly only shows the last point the drone was prior to losing connection. That in itself is not much help but, what I am curious about is why the drone icon seems to be facing back towards the home point (see image 2), when if it was actually on the way on the way to waypoint 2 or returning from the mission, in either case, it would have been facing towards POI1.
so this leads me to believe that if the direction of the icon does indeed indicate the flight direction, that perhaps it was on RTH for some reason.
However this too seems unlikely since the flight log shows it took only about 1.5 minutes for the drone to lose connection. So I believe that's a pretty short time to go on RTH and chances are its really where the connection was lost.
So the question remains- why does the drone face to the homepoint on the "lost signal" location.Is it possible that the direction of the icon just doesn't mean anything?

I lost here guys. please help!!!

Thanks!Screenshot_20181108-174712_Litchi - Mission waypoints.jpgScreenshot_20181108-221917_Litchi - Last seen location - notice it's heading back.jpgScreenshot_20181108-222926_Litchi - close up on last way points.jpg
 

SpinItUp

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Itchy flight logs are useless to me? (I can't see much info)
If you were on top you would have had a chance of keeping a signal but being lower from launch surrounded by residential buildings and flying extremely low is asking for the signal to cut out.
The TRH RTH isn't going to take into account the elevation change from the home point I believe (set @?)
 
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sar104

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Even without your mission plan I think the problem is fairly apparent. Your last waypoint (6) was set 33 m above the takeoff point at 677 m MSL, i.e. 710 m. But the ground elevation at waypoint 6, according to GE, is 712 m. Your mission flew it into the ground. I would check around waypoint 6.

Mission profile with elevation:

screenshot248.jpg
 

RayOZ

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Were you looking at the screen at all while it was flying the waypoint mission? I am guessing if you did, perhaps might realise you need to fly higher. You can't just hit Go and then take your eyes of the drone or screen, and your fingers off the RC. Always be ready to hit Stop or Pause while it's flying its mission.
 

SpinItUp

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Further, 'Find my drone' supposedly only shows the last point the drone was prior to losing connection. That in itself is not much help but, what I am curious about is why the drone icon seems to be facing back towards the home point (see image 2), when if it was actually on the way on the way to waypoint 2 or returning from the mission, in either case, it would have been facing towards POI1.
so this leads me to believe that if the direction of the icon does indeed indicate the flight direction, that perhaps it was on RTH for some reason.


no Thanks!
Screenshot_20181108-221917_Litchi - Last seen location - notice it's heading back.jpg

It seems to be pointing North
here
On changing direction it may have been greeted by an obstacle. As you were so low I guess it just gave up because it was surrounded by elevation of the land or residential obstacles.
Maybe there or in the basement of the swimming pool joint?
Take your pick:confused:Itchycoo.jpg
 
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gullisig

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Hello brilliant people.

Today I tried to use the Litchi App for the second time on my life. Guess what? after about a minute signal was lost and drone never returned home.
I live on a small mountain and the waypoints are marked where terrain is ascending - see images 1+3 below. Also, I defined the finish action as 'reverse' so I assume it would simply follow the very same mission only in reverse. So I followed the entire mission path and found nothing on the ground. What I also found however is some tall trees that I was dumb enough not to look out for when planning the mission on my Android Tablet.

Any thoughts on where the drone is likely to be along this mission path? all the documents pertaining to this mission are on my Google Drive folder:
Litchi Mission - Lost - Google Drive

Further, 'Find my drone' supposedly only shows the last point the drone was prior to losing connection. That in itself is not much help but, what I am curious about is why the drone icon seems to be facing back towards the home point (see image 2), when if it was actually on the way on the way to waypoint 2 or returning from the mission, in either case, it would have been facing towards POI1.
so this leads me to believe that if the direction of the icon does indeed indicate the flight direction, that perhaps it was on RTH for some reason.
However this too seems unlikely since the flight log shows it took only about 1.5 minutes for the drone to lose connection. So I believe that's a pretty short time to go on RTH and chances are its really where the connection was lost.
So the question remains- why does the drone face to the homepoint on the "lost signal" location.Is it possible that the direction of the icon just doesn't mean anything?

I lost here guys. please help!!!

Thanks!View attachment 52754View attachment 52755View attachment 52756
You can also share your flight plan with Litchi Hub. Then we can see all settings on each waypoint.
 

sar104

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View attachment 52774

It seems to be pointing North
here
On changing direction it may have been greeted by an obstacle. As you were so low I guess it just gave up because it was surrounded by elevation of the land or residential obstacles.
Maybe there or in the basement of the swimming pool joint?
Take your pick:confused:View attachment 52776
At that location it was 36 m AGL. It's unlikely to have hit anything. The last recorded (Find my drone) point is a red herring - that's just where it lost the connection.

The profile was 30 m AGL at WP2, 12 AGL at WP3, 14 m AGL at WP4, 21 m AGL at WP5, and ground level at WP6. So while it's certainly possible that it hit trees or structures from WP2 onwards, it definitely didn't make it past WP6.
 
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DaJuice

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You can also share your flight plan with Litchi Hub. Then we can see all settings on each waypoint.
Thanks, gullisig! Great idea, here's the link:
Mission Hub - Litchi
Even without your mission plan I think the problem is fairly apparent. Your last waypoint (6) was set 33 m above the takeoff point at 677 m MSL, i.e. 710 m. But the ground elevation at waypoint 6, according to GE, is 712 m. Your mission flew it into the ground. I would check around waypoint 6.

Mission profile with elevation:

View attachment 52759
Thanks for looking into my mission, sar104. I'm going to head out to where the ground elevates right now and search for it
 

JoelP

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Sorry you lost your drone. If you find it, and are willing to fly Litchi again, you should fly a Virtual Litchi mission before you fly in Litchi. It isn’t perfect, but it would have made it obvious that your mission was going to fly into the ground or other fixed obstacles.
 
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Cdcolt

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I hope you find your drone. If you do, don’t be afraid to use Litchi Mission Hub again. Your problem seems to be that your waypoints used “Above Home Point” instead of “Above Ground”. I’ve used Mission Hub quite a few times and found that there are a couple things that help.

1. Know the terrain and height of objects there (where you are sending your drone).
2. Make sure you set the elevation to Above Ground taking into account any towers or buildings you may be flying near.
3. If you set “Finish Action” to Reverse and used Above Ground for your altitude you should be good, BUT, you may want to just plot a few return points again taking into consideration elevation changes.
 

DaJuice

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Even without your mission plan I think the problem is fairly apparent. Your last waypoint (6) was set 33 m above the takeoff point at 677 m MSL, i.e. 710 m. But the ground elevation at waypoint 6, according to GE, is 712 m. Your mission flew it into the ground. I would check around waypoint 6.

Mission profile with elevation:

View attachment 52759
Dear fellows,
I thought I might update. The drone was found by someone and they found me and I eventually got it back. All the estimates of where I thought it may be were off, including the ones offered in this thread. It crashed into a tree at the end of the mission.
My question to you guys is this: since i uploaded the mission to litchi hub and shared it for everyone to see, why was the 'above ground' setting so misleading? in other words, having all the data straight forward, why did everyone believe it had crashed in a different place.
Here's the link to the video of the mission. it's clear to see how it crashed:

second question is, do the anti collision sensors work at all during a waypoint mission? or are the disabled like when using the special flight modes in dji go4?
trying to figure out why it crashed into a fairly big and visible tree.
 

sar104

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Dear fellows,
I thought I might update. The drone was found by someone and they found me and I eventually got it back. All the estimates of where I thought it may be were off, including the ones offered in this thread. It crashed into a tree at the end of the mission.
My question to you guys is this: since i uploaded the mission to litchi hub and shared it for everyone to see, why was the 'above ground' setting so misleading? in other words, having all the data straight forward, why did everyone believe it had crashed in a different place.
Here's the link to the video of the mission. it's clear to see how it crashed:

second question is, do the anti collision sensors work at all during a waypoint mission? or are the disabled like when using the special flight modes in dji go4?
trying to figure out why it crashed into a fairly big and visible tree.
From the video it is quite clear that it crashed exactly where I pointed out it would crash in post #3 – as it descended towards waypoint 6, which was set much too low.
 

SpinItUp

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So it ended failed at/near WP 5 (or as 104 points out ready to descend onto WP 6)
The question is how did you miscalculate the elevation by so much?
 

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