Mavic Air fell out of the sky

dayslastserenade · Feb 13, 2018

Hey all, it was suggested that I post this here.

I was flying my new Mavic air out a ways and hit return to home to bring it back. Everything seemed normal, but 30 seconds into the return to home function, the drone seems to have flipped over. There was no wind alert or any warnings. The drone seems to have tried correcting from the free fall, but was only able to slow down a bit. The drone crashed onto a frozen lake, but I was able to locate it due to the gps. Luckily there was no damage.

I have flown it a few times since and it hasn't acted strange at all... but I'm nervous that it could happen again.

I'm not sure what might have gone wrong, so if any of you have any input, let me know!

Former Member · Feb 13, 2018

FF to 4m16s to see the crash.

Glad you got your drone back.

Aerial-Pixel · Feb 13, 2018

Yikes, glad the lake was frozen and had snow to cushion the blow. Have you analyzed the log yet? are you on the latest firmware?

dayslastserenade · Feb 13, 2018

Aerial-Pixel said:
Yikes, glad the lake was frozen and had snow to cushion the blow. Have you analyzed the log yet? are you on the latest firmware?

I’m on the latest firmware. When I look at the flight log, right before it goes down I see “Warning: Motor obstructed.” Not entirely sure what could have obstructed it though

Aerial-Pixel · Feb 13, 2018

OOooh, possible bird strike? Didn't see any sigh of it though in the footage.

dayslastserenade · Feb 13, 2018

Aerial-Pixel said:
OOooh, possible bird strike? Didn't see any sigh of it though in the footage.

Yeah I don’t see anything either, and there were no feathers down below when I found the drone haha. It was cold, maybe around 20 degrees, and it was a bit foggy, but I also didn’t notice any icing or anything like that either. I’m just a bit scared to fly it around currently

Jbourne210 · Feb 13, 2018

Possible blade icing? IF icing were to have occurred, the blades would have had to spin faster and faster to counter the lack of efficiency of the airfoil. Maybe the system interpreted that as an obstruction? Just my .02!

Glad you got her back though!!

EDIT - Tried posting this a bit ago, and my system locked. I see you already considered blade icing as a possible culprit. Regarding trusting her again, I'm assuming you did a VERY detailed post flight after the incident? A tiny little surface crack could be disastrous in the air...

Take offs are optional. Landings are mandatory...

dayslastserenade · Feb 13, 2018

Jbourne210 said:
Possible blade icing? IF icing were to have occurred, the blades would have had to spin faster and faster to counter the lack of efficiency of the airfoil. Maybe the system interpreted that as an obstruction? Just my .02!

Glad you got her back though!!

EDIT - Tried posting this a bit ago, and my system locked. I see you already considered blade icing as a possible culprit. Regarding trusting her again, I'm assuming you did a VERY detailed post flight after the incident? A tiny little surface crack could be disastrous in the air...

Take offs are optional. Landings are mandatory...

Correct, I checked it all out. I've flown it for another 20 minutes since and it's handled perfectly. I'm just nervous because it was handling perfectly right until it fell in the first place lol. It could have been icing, the air in the video does look a bit foggy, and at that temp ice certainly could happen. I feel like I should have noticed something if that were the case, but perhaps the gimbal was doing too good of a job?

Kilrah · Feb 13, 2018

Almost certainly prop icing. The fast moving foggy patches that could be seen at the end were a "nope out of there aka go down NOW" sign.
The flight controller and gimbal will fully compensate it so that it's invisible until it can't anymore, on/off situation.

msinger · Feb 13, 2018

dayslastserenade said:
perhaps the gimbal was doing too good of a job?

If you look at the data in your TXT flight log, you'll be able to see if the drone and/or gimbal was tilting. You can upload your flight log here.

dayslastserenade · Feb 13, 2018

Kilrah said:
Almost certainly prop icing. The fast moving foggy patches that could be seen at the end were a "nope out of there aka go down NOW" sign.
The flight controller and gimbal will fully compensate it so that it's invisible until it can't anymore, on/off situation.

Good info. Makes me feel better to know a reason for the fall, rather than having some uncertainty. Thanks!

dayslastserenade · Feb 13, 2018

msinger said:
If you look at the data in your TXT flight log, you'll be able to see if the drone and/or gimbal was tilting. You can upload your flight log here.

Looks like itunes is required to view the full log, so I'll do this when I get home, thanks a lot

DavidNDC · Feb 13, 2018

Kilrah said:
Almost certainly prop icing.

My thoughts as well. It wouldn't take much to disrupt the airfoil on those little plastic props and it looks like it went down soon after skirting that low ceiling.

But to be safe, I'd hover it for at least three batteries at a comfortable altitude before your next outing.

dayslastserenade · Feb 13, 2018

msinger said:
If you look at the data in your TXT flight log, you'll be able to see if the drone and/or gimbal was tilting. You can upload your flight log here.

I found the logs, but I'm not entirely sure what to make of them. I see the motor obstructed error, but the altitude never changes during it's fall.

DJI Flight Log Viewer - PhantomHelp.com

Hopefully that link works for you

msinger · Feb 13, 2018

If you convert your flight log data with this tool, you'll see one additional line at the very end of the flight log that shows the motors failed due to "ESC_StallNearGround". I'm not sure what that means. Maybe run it by DJI Support.

maven4336 · Feb 13, 2018

Wow tough cookie, ice I would say, my mavic would have been destroyed, watched a you tube other day some one was trying everything to demolish his air and that is a bullet proof drone, glad she back in your hands, good footage way to much sidewind and snow no dought was your issue

dayslastserenade · Feb 13, 2018

msinger said:
If you convert your flight log data with this tool, you'll see one additional line at the very end of the flight log that shows the motors failed due to "ESC_StallNearGround". I'm not sure what that means. Maybe run it by DJI Support.

Thanks for looking into it. That csv is hard to read, but I saw what you were talking about. I emailed DJI support to let them know, I'll report back here if they let me know anything further. Thanks again!

dayslastserenade · Feb 14, 2018

maven4336 said:
Wow tough cookie, ice I would say, my mavic would have been destroyed, watched a you tube other day some one was trying everything to demolish his air and that is a bullet proof drone, glad she back in your hands, good footage way to much sidewind and snow no dought was your issue

Icing makes the most sense to me. I did watch some other drone videos on youtube that showed icing, and they didn't just fall out of the air suddenly like mine did, so I'm still not 100% certain. There wasn't really any wind while I was out, at least not at my location. Over the lake might have been a different story though. I was really nervous when it went down over the lake. I knew it was frozen, and I wasn't sure just how frozen, though we've been sub freezing for weeks now mostly. I was quite nervous to go walk across the lake to retrieve it as well. Felt a bit better when I saw other people out there, as well as snowmobile tracks.

sar104 · Feb 14, 2018

dayslastserenade said:
Thanks for looking into it. That csv is hard to read, but I saw what you were talking about. I emailed DJI support to let them know, I'll report back here if they let me know anything further. Thanks again!

If you get the DAT file from either the aircraft of the mobile device it will have more detailed motor data.