Lost controls of Mavic Air while mid air

[JoeyT]

Dear community,

I guess I can hit the queue of devastated Mavic air owners. 23-12-18 I treated myself on a Mavic Air combo pack for Christmas after saving up for a year.

Today was my second actual day of using it. We hit the beach to record some fun footage. I calibrated the drone per usual, made sure I selected 'return to home' and took off without any hassle. 3 minutes into the flight we were flying above water and just as I wanted to return the aircraft, my RC lost connection on a 341m distance. I've waited patiently, did not restart the RC or app. Battery of aircraft was fully charged when I took off (85% charge when i lost connection). During the flight I was connected to 15-20 satellites. Since we were on a cliff, the drone was actually flying -3.91m below my position. Nothing was standing in between me and my drone, I had clear sight on this sunny day. The connection was never restored.

Here's where it gets interesting. After I almost gave up on the drone. It showed up high right above me (note: this happened without any form of connection to the RC). The return to home mode kicked in. It lowered in altitude and then all of the sudden drifted off back above the water where it kept declining and eventually disappeared out of sight. The replay of the flight won't show the last event. It will just show me flying the drone until I got a message of high wind velocity, return to home asap and lost connection while it was above water. I pressed RTH straight after, but the connection got lost before I could do so. I've already opened a case with DJI right after it happened, but I figured this friendly community might show so insight too. My guess it that it got caught up in unexpected wind and had a hard time to return to home. Which still raises my question; why did it return right above my (return to home) location but drifted off?

I can't even begin to tell ou guys how devistated I am. I've been talking about buying a drone for ages and right into day 2 of flying I lost it to reason unknown. Peep the last photo of me
Being happy editing my first day flight into a little highlight reel. :-(

Ps. How do I provide you guys with a flight log?

 

[calmar81]

I am very sorry for you and hope, someone can help you here. :-(

 

[Jeytea]

sorry for your loss.
Why did you calibrate the compass? were you prompted to do that in the app or did you do it only as a precaution? ?

 

[Meta4]

Ps. How do I provide you guys with a flight log?

Go to: DJI Flight Log Viewer - Phantom Help
follow the instructions there and upload your're and upload your flight record from your phone or tablet.
That will give you a detailed report.
Copy the link for that report and come back and post a link to that report.

lost connection while it was above water. I pressed RTH straight after

One question that might be important:
How far from you was the drone when you pressed RTH?

 

[JoeyT]

Go to: DJI Flight Log Viewer - Phantom Help
follow the instructions there and upload your're and upload your flight record from your phone or tablet.
That will give you a detailed report.
Copy the link for that report and come back and post a link to that report.

One question that might be important:
How far from you was the drone when you pressed RTH?

--------
The drone was 341m away from me when the connection got lost and never returned. Just a second before that happened I got a warning of high wind and that I should RTH asap. Which I did, but the connection was already lost before I had the chance. After that it returned on it's own but it floated away and landed in the water or bushes you can't access).

 

[JoeyT]

sorry for your loss.
Why did you calibrate the compass? were you prompted to do that in the app or did you do it only as a precaution? ?

I did it because the app told me so upon flying. It couldn't take off without the calibration so I did exactly that and everything was fine. I always check any possible warning before any take off. I've had to do this a few times before when I started up the drone last time.

 

[Meta4]

The drone was 341m away from me when the connection got lost and never returned.

You mentioned pressing RTH. "I pressed RTH straight after, but the connection got lost "
How far away was the drone when you pressed RTH?

If you post your flight data, I will analyse it and tell you what I can see in it.

 

[JoeyT]

here is my flight log... hope this is the right document.

 

[Meta4]

here is my flight log... hope this is the right document.

Will you please answer the question I asked?

 

[JoeyT]

You mentioned pressing RTH. "I pressed RTH straight after, but the connection got lost "
How far away was the drone when you pressed RTH?

If you post your flight data, I will analyse it and tell you what I can see in it.

The drone was 341m away from me when I pressed it. As you can see in the log, the drone is facing towards my location. I was showing them the footage on screen and said, "I'll get the drone to return to us so we can head to the beach." At that very moment when the "high wind velocity" notification showed up, the connection got lost in the process. Leaving me no chance to press RTH on time. Where the log ends, is where i pressed RTH right after.

 

[JoeyT]

Will you please answer the question I asked?

Also, I pressed RTH multiple times after that. But without any result due to loss of connection. It returned to my location on its own when the battery got low, but for some reason, it floated away back to the water and then slowly lost altitude. It's RTH on it's own and floating away hasn't been recorded by the log.

 

[Meta4]

The drone was 341m away from me when I pressed it. As you can see in the log, the drone is facing towards my location. I was showing them the footage on screen and said, "I'll get the drone to return to us so we can head to the beach." At that very moment when the "high wind velocity" notification showed up, the connection got lost in the process. Leaving me no chance to press RTH on time. Where the log ends, is where i pressed RTH right after.

Thankyou .. the distance is good as it eliminates one possibility but pressing RTH multiple times might not be good as if there was a connection, pressing RTH while RTH is active will cancel RTH.
In a situation like that, the best strategy is to switch off the controller to be sure there is no signal and so initiate RTH.

Unfortunately there isn't much that can be seen in your flight data as all the important stuff happens after connection is lost.
I can't find any helpful clues.

 

[JoeyT]

Thankyou .. the distance is good as it eliminates one possibility but pressing RTH multiple times might not be good as if there was a connection, pressing RTH while RTH is active will cancel RTH.
In a situation like that, the best strategy is to switch off the controller to be sure there is no signal and so initiate RTH.

Unfortunately there isn't much that can be seen in your flight data as all the important stuff happens after connection is lost.
I can't find any helpful clues.

I was afraid of that yea. I really have no idea why my connection could've dropped just like that. I've had clear line of sight. conditions were perfect, apart from the moment it noticed high wind for which I wanted to return asap but it was already too late. Do you know what DJI does about this in a case like this?

 

[tcope]

Here is the uploaded file:

DJI Flight Log Viewer - PhantomHelp.com

 

[Meta4]

I was afraid of that yea. I really have no idea why my connection could've dropped just like that. I've had clear line of sight. conditions were perfect, apart from the moment it noticed high wind for which I wanted to return asap but it was already too late

Normally, losing connection would not be an issue because it would initiate RTH.
The reason RTH did not bring the drone back is a mystery.
If connection had been restored, that should have shown in the data, so it's unlikely that you cancelled by pressing RTH.
The obvious possible issue to look into is wind.
The wind warning you got is probably not important.
Looking at your joystick input and speeds, I think the wind was blowing toward shore?
I so, that also would eliminate another possible cause.

Do you know what DJI does about this in a case like this?

DJI will only be able to act if there is clear evidence of a DJI issue being the cause. No evidence and they won't do anything.

 

[Keule]

Might be a wind issue here:

 

[Meta4]

The obvious possible issue to look into is wind.

If you had the wind in your face while watching the drone, the wind is no problem.
But if the wind was on your back as the Airdata plot indicates, that's a smoking gun.
If the wind strength was more than RTH can deal with, that is likely to be the cause of the loss.

It's never a good idea to fly off downwind in a strong wind situation.
It means a battle against a headwind to come home and RTH lies slower than the drone does when you do the driving.

 

[JoeyT]

Might be a wind issue here:

View attachment 56867
View attachment 56868

Yeah that would indicate why it might had trouble flying back. However, it DID get back on it's own. And that still doesn't explain why my connection got lost in clear line of sight. Right?

 

[RayOZ]

RTH would mean that the drone would rise up to the RTH height, default 30m. It explains why it appeared right above you. As for taking awhile, well it had to go up and fight the wind to return. Wind was > 40kph below take off altitude, I would expect the wind would be stronger when it got 30m up. As for initial loss of connection, if you flew it below the cliff, and there's no direct line of sight from RC to AC, then that's the cause. Why it didn't reconnect after it rose up to RTH height, it hard to explain.
Without the drone, I don't think DJI would be able to help you. DJI care refresh would still the the drone. Without flight logs, DJI won't assume it's a malfunction. Maybe they feel Chrismassy, and give you the benefit of the doubt, but unlikely.
2nd day of owning your drone. Flying over water with high wind. Very brave move. Not something I would've attempted.

 

[JoeyT]

RTH would mean that the drone would rise up to the RTH height, default 30m. It explains why it appeared right above you. As for taking awhile, well it had to go up and fight the wind to return. Wind was > 40kph below take off altitude, I would expect the wind would be stronger when it got 30m up. As for initial loss of connection, if you flew it below the cliff, and there's no direct line of sight from RC to AC, then that's the cause. Why it didn't reconnect after it rose up to RTH height, it hard to explain.
Without the drone, I don't think DJI would be able to help you. DJI care refresh would still the the drone. Without flight logs, DJI won't assume it's a malfunction. Maybe they feel Chrismassy, and give you the benefit of the doubt, but unlikely.
2nd day of owning your drone. Flying over water with high wind. Very brave move. Not something I would've attempted.

Thank you for your comment!

I initially flew higher than my own position, but lowered to -3.9m when I got the 120m altitude warning. My own position was 112m. Wind conditions were perfect when I took off (no warnings), as the log shows, but it must've gotten more windy when I flew a little off the coast. However, I never lost sight of the drone which then indicates there should be a form of connection between AC and RC. Which still wouldn't have been the biggest issue since the drone did return on it's own to my exact location but did not manage to land and flew off again. Unfortunately that doesn't show up in the log. There wasn't much I could do after I got the high wind velocity warning since the connection dropped straight after.

Let's just hope for the best.