Mavic Air lost control and hovered into a tree

[redmosquito1983]

Problem? Dropped signal and lost control 100' up 20' away from me and it drifted into a tree and came down hard

Was unit in a crash? Yes

What have you tried so far? Swearing, lots of cursing, called retailer they said call DJI, called local DJI branded store and they can repair

What device are you using ( iphone , ipad, Samsung , etc)? iPhone Xs

What firmware are you running ( aircraft, remote controller)? All current

What Go app version are you using? Current

Any modification? No

Did you change anything or install any apps? No

Do you have a video or pictures of the problem? I have a video of it tumbling down through the tree, not much to see except it hovering in and around the pine tree for about a minute until the rear props contact a branch and it goes tumbling down.


Hello everyone, sadly this is my first post here after my Mavic Air crashed. So today I took my Mavic Air with me to work, I work for the local electric utility in substations and was going to be at one today that has some neat lakes and houses around that I thought would be cool to fly over. I know the manual says substations are a no go area but I was technically outside in the driveway a good 20' away from anything energized and the 40kV stuff was even further away so I figured I was good. And I was, after acquiring a good GPS signal I went up to approx 100' moved over the substation mat for a little bit then began raising up and moving towards my intended target of a lake 1/2 mile away. Came back in sport mode to the general area and switched over to regular mode to bring it home. Started bringing it down doing some messing around thinking I'd be fine since heading out I had no issues, unfortunately once I got to 100' I lost all connections and control over the drone. It drifted towards a pine tree, hovered for about 1 min and then clipped a branch pinballing through the tree before finally taking a hard landing on a truck in the driveway. Truck was fine but the drone isn't, more on that at the end. Now, I assume it dropped signal because I was over a substation, but I don't understand why it wasn't an issue headed out but was coming back. One other time I dropped signal like this in my driveway doing a dronie it dropped signal and returned home and hovered just above my head, it did something similar this time but hit the tree. I think this time it tried to go home but had its home point off and went into the tree instead, with no controller connected it just sat there until it crashed.

But, can you guys tell from the flight log if something else happened or if something is wrong with the drone? This is the flight log I uploaded to phantom help, video from the drone memory card goes about 2 minutes longer.
DJI Flight Log Viewer - PhantomHelp.com

With all that being said, I assume since I was over a substation DJI will not warranty this for me? which is fine, the manual explicitly says not to fly near them I guess their definition of near is a lot different than mine, haha. The positive is after recalibrating the sensors and replacing the props it flys again, but the rear landing gear/bottom motor cover is broken as is the front. The front one acts as the pivot for the antenna, somehow the antenna didn't break off but the piece its mounted into is broken so it won't stay folder or unfolded. I know the rear will just pop out and in, the front looks like it screws and snaps in, but it looks like I have to buy an entire arm to repair it? is that so? and can I just replace the hinge part or am I looking at an entire arm replacement?

Thanks everyone, pretty bummed.

 

[BD0G]

Typically when taking off near large metal objects the compass is not able to properly determine which way is true Magnetic North , South, East , and West. It sets up the compass incorrectly. Then the compass compares its values with the GPS signal and they are not able to properly determine which way the Mavic is actually travelling as there are conflicting reports.

Then the internal controller tries and tries to correct these values until it decides to reboot. Connection is lost and the Mavic flies off to what it thinks is its Return to Home point which is totally incorrect. In your case so incorrect that it chose to fly into a pine tree.

This is a guesstimate from all the other "big metal object" take off point wacky crash scenarios that I have read over and over again on the site.

To determine the exact cause then @sar104 will need to look over the flight log you posted and elaborate.

 

[redmosquito1983]

Whats close to a big metal object though? 1 foot? 5 feet? 100 feet? and wouldn't the compass throw an error if I was to close? I honestly have no clue, I know if I'm within a foot or so of my vehicle or steel barn at home it tells me to recalibrate but this time it didnt.

I got the .DAT file off the drone, would that make figuring this out easier? I'm mostly hoping to determine if this was my error or an error with the drone itself for future avoidance.

 

[BD0G]

Yes. Any large metal object including Rebar within the substructure of concrete.
The .DAT file you posted will be helpful for the experts to dissect what happened. Please hold...

 

[sar104]

The cause of the signal loss isn't evident in the log. It could be that you simply had the antennas oriented vertically with the aircraft directly above you, but I suspect that there was another issue behind that. I doubt that it was related to the substation since the connection was fine up to that point.

What happened after the disconnect obviously isn't recorded, but according to the kml flight track you launched from under the tree, and climbed out at an angle to avoid it. When RTH was initiated on connection loss the aircraft was close to the home point (7 m north and 32 m above) and simply went to autoland, clipping a tree on the way down. That's one of the hazards of launching very close to trees.

 

[redmosquito1983]

Thanks sar104, would the .DAT file from the drone show what happened to the signal? Like I said there was almost 2 minutes after dropping signal that it floated in the tree, I'd really like to know if it was my fault or the drones fault. I used the DJI Assistant to pull the .DAT file but am having a hard time doing anything with it because I don't know what I'm doing. I did download DatCon but no joy there either, but I haven't spent much time on it.

I was several feet away from the trees when I launched and had clear skies above me. I was much closer to the fence but the trees are close so I did knowlingly take risks; unfortunately with no reward, haha.

Would this be something DJI would likely cover under warranty?

 

[sar104]

Thanks sar104, would the .DAT file from the drone show what happened to the signal? Like I said there was almost 2 minutes after dropping signal that it floated in the tree, I'd really like to know if it was my fault or the drones fault. I used the DJI Assistant to pull the .DAT file but am having a hard time doing anything with it because I don't know what I'm doing. I did download DatCon but no joy there either, but I haven't spent much time on it.

I was several feet away from the trees when I launched and had clear skies above me. I was much closer to the fence but the trees are close so I did knowlingly take risks; unfortunately with no reward, haha.

Would this be something DJI would likely cover under warranty?

Unfortunately the aircraft DAT file from the MA is not readable due to the encryption used. DJI will be able to read it, and you will probably need to persuade them that the direct cause of the crash was a loss of signal due to equipment issues, rather than the unsuitable launch site, if you want them to cover it under warranty. It's worth asking.

 

[Meta4]

Thanks sar104, would the .DAT file from the drone show what happened to the signal?

All any recorded data could tell you about the signal is that you had signal and then you didn't.
It might have been due to poor antenna geometry with the drone being high up above the controller or perhaps being blocked by tree cover.

I was several feet away from the trees when I launched and had clear skies above me. I was much closer to the fence but the trees are close so I did knowlingly take risks; unfortunately with no reward, haha.
Would this be something DJI would likely cover under warranty?

Flying close to trees and other obstacles is probably the biggest cause of crashes.
Your drone performed as it is programmed to and returned after losing signal.
It was unfortunate for you that the return path led it straight into danger.
Somehow I don't think DJI would see that as their fault.

 

[redmosquito1983]

Bummer, thanks though. I'll ask but I'm willing to bet they wont cover it unless I could prove without a doubt it was equipment error that caused it to drop signal. Which I can't. I'm sure they'll go right to me flying over a substation to deny the claim, but worth the shot.

I agree Meta4, but worth asking I guess.

 

[BD0G]

Always try to have DJI cover the incident. Open a Support Ticket via the website.

At worst I have read multiple times about DJI offering a compromise and discounting the cost of a new Mavic replacement. Personal articles insurance is also something to look into for your future drone journey. Statefarm offers this coverage in many states (not California) and it is approximately $60.00 per year.

 

[redmosquito1983]

I started a ticket last night and will send it out later today or Monday. My only concern is they’ll deny warranty because I was by the substation and once that happens it seems like either they fix it at whatever cost or I pay them $65 plus shipping to send it back.

Now I’m pretty handy, so I looked at the tear down video on YouTube. But there are so many small connections and pieces that I’m sure I’ll break it so it’s going in for repair. The local dji branded store is $150 and $30 per arm, looking over the drone this morning I’m going to need both front and maybe a rear arm. Dji charges $65 an hour and $15 per arm so I figure it’ll be close in cost.

Only difference will be the local store will be much quicker. Sending it in maybe DJI will figure out why I lost signal and repair that issue under warranty where the store likely won’t look into it

As for State Farm, I called my agent when I got it to insure it. But, it didn’t meet the minimum monthly cost so I was in the process of getting some jewelry appraised to bring the monthly cost up. It’s just taking a while and here I am.

 

[Turn11]

@Thunderdrones on this site repairs a LOT if not all of the AC that DJI manufactures. As a LOT of people on here can attest he is thorough, reasonable and pretty darn fast. He is in Duluth, GA. Here is a link to his repair information.
You may want to delay shipping until you have had a chance to chat with him, a day won't matter. Just a thought.

 

[redmosquito1983]

Update - So I got the data analysis from DJI and they say it was my fault. They claim that at 5:52 an external impact occurred causing the unit to fall from the sky and that I was throttle down and forward pitch. However the video shows at 5:52 the drone stops, turns and flys to the tree and hovers for a full 2:41 before crashing. The phone flight log shows the flight stop at 5:52.7 seconds at 105’ high 24’ from home throttle down and right. Nothing after that.

It seems like they didn’t view the video maybe?

What are my odds of DJI changing their decision after I appeal to them? I sent this info to the tech and am currently waiting on a reply, but they say I damaged the core board at $208, total of $412. Not expecting that cost and a little upset because the unit lost control with out me doing anything to make it drop.

 

[sar104]

Update - So I got the data analysis from DJI and they say it was my fault. They claim that at 5:52 an external impact occurred causing the unit to fall from the sky and that I was throttle down and forward pitch. However the video shows at 5:52 the drone stops, turns and flys to the tree and hovers for a full 2:41 before crashing. The phone flight log shows the flight stop at 5:52.7 seconds at 105’ high 24’ from home throttle down and right. Nothing after that.

It seems like they didn’t view the video maybe?

What are my odds of DJI changing their decision after I appeal to them? I sent this info to the tech and am currently waiting on a reply, but they say I damaged the core board at $208, total of $412. Not expecting that cost and a little upset because the unit lost control with out me doing anything to make it drop.

Get back to them and confirm whether they watched the video, which they quite possibly didn't. No harm asking.

 

[redmosquito1983]

Get back to them and confirm whether they watched the video, which they quite possibly didn't. No harm asking.

I emailed the tech about an hour ago and waiting on his reply. I’m inpatient so I called dji North America and talked to someone there, he’s escalating the case and disputed the amount based on what the video I uploaded shows. So I guess we shall see what they say. Fingers crossed they approve it under warranty. If they denied it I expected it to be denied because they’d claim I did something wrong to lose signal.

 

[redmosquito1983]

Well, got an email back tonight after they viewed the video. They said that since I took off near a substation, with trees near me, and quoted antenna dead spots in the RC, that any of those could have caused the dropped signal and signal loss isn't covered under warranty. I call BS because if any of those would cause signal loss it would have lost it on the way out not when bringing it down, and at the time of signal loss I had clear line of sight and was pointing the RC towards the drone.

I was 40 feet from anything energized the closest being energized at 4.8kV in a large steel box thats grounded, shielding any EMFs, not to mention the drone was between me and the switch gear. Myself and the drone were in a hole of trees and I had clear line of sight, and the RC antennas were directed towards the drone. If it was caused by "antenna dead angle" why didn't I get a warning as the signal got weak? It doesn't make sense to me.

Either way, I don't feel like I'm going to win this argument. They offered the possibility of getting a discount to repair it, I'll take it but not happily. I'd like them to drop either the labor or parts charges, but I expect maybe 10% off if any. Really disappointed, hopefully they send me a refurb drone so I can get it back asap.

Anyone have experience with them discounting repair work?