Drone disconnects and flyaway

ascho7 · Nov 20, 2017

Today I flew my drone on a fairly windy day. I am quite comfortable flying it so I was confident. About halfway through flight, I believe I hit something (most likely a bird) as my drone spun a bunch and did flips. When it recovered it was only letting me fly one way. I tried to land but as my drone had gotten to 20% and 19 satellites my drone just decided to disconnect. I looked where the last coordinates were with the find my drone but I couldn’t find anything. I believe that this wasn’t my fault and I’m not sure what to do. I spent a whole summer saving up for this to lose it. Maybe dji will be able to replace the drone because I don’t feel it was my problem. If anyone had any comments on this let me know, thanks!

linuxglobal · Nov 20, 2017

Do you have the flight log for this event?? video footage of how it carried out.

You should see the flight lot under "my flights" on the dji go 4 app. That will provide at least some info as to what happened as a playback.
Magnetic interference can often cause some serious issues but I am not sure exactly how this will be handled.

ascho7 · Nov 20, 2017

linuxglobal said:
Do you have the flight log for this event?? video footage of how it carried out.

You should see the flight lot under "my flights" on the dji go 4 app. That will provide at least some info as to what happened as a playback.
Magnetic interference can often cause some serious issues but I am not sure exactly how this will be handled.

Yes, I can give the flight log. With the flight log, the last recorded detail was set “landing” at -439ft but that really doesn’t tell me anything. No video as it only sent me one but it didn’t give me any information. The only reason why magnetic interference wouldn’t make sense is I had a full 19 satellites then it just dropped off. I don’t understand because I was still in distance, I couldn’t see it but I could see where it landed because I was on a mountain and I could look out down to where it was supposed to land and crash.

ascho7 · Nov 20, 2017

Airdata UAV - Flight Data Analysis for Drones

linuxglobal · Nov 20, 2017

Looking at the Log it looks like you ran the battery to the limit, way too low and surpassed the RTH estimate.

The unit auto landed due to a lack of battery power, it lands at 15% or less. I feel the landscape may have damaged the drone as it tried to land and crashed out of sight or into trees.

Based on the log location, did you check the GPS location of the crash site for the drone ? it also appears you were flying in ATTI mode which is sensor-less and will not use GPS lock for any movements (Drifts with the wind). Im not a pro so others can chime in on your log but the end is confusing for sure. Looks like video was started, do you have those video and picture files on the app ? would be under your media. Perhaps flying in reverse or drifting near the end.

From the looks of the log there was no loss of signal until it reached the critically low battery.
Did you decline the RTH during the flight ?

ascho7 · Nov 20, 2017

linuxglobal said:
Looking at the Log it looks like you ran the battery to the limit, way too low and surpassed the RTH estimate.

The unit auto landed due to a lack of battery power, it lands at 15% or less. I feel the landscape may have damaged the drone as it tried to land and crashed out of sight or into trees.

Based on the log location, did you check the GPS location of the crash site for the drone ? it also appears you were flying in ATTI mode which is sensor-less and will not use GPS lock for any movements (Drifts with the wind). Im not a pro so others can chime in on your log but the end is confusing for sure. Looks like video was started, do you have those video and picture files on the app ? would be under your media. Perhaps flying in reverse or drifting near the end.

From the looks of the log there was no loss of signal until it reached the critically low battery.
Did you decline the RTH during the flight ?

Yes, about halfway through the flight you could see it was trying to return to home but it just wouldn't. the wind was strong but not so strong I couldn't fly back. I had started to try and land the drone as it was my best hope, I knew it wouldn't return to home. I knew after it had "hit" whatever it had it hit or why it wouldn't fly back to home I had panicked and had tried to descend. I had the drone under control until I was about 3721.9 feet away, when my mavic had freaked out. I tried RTH at 9 minutes in, 3,000 feet away from the freakout but it just wouldn't go that direction. I had started to try to land with 30% but it just wouldn't really work with me. I was calm as I knew I could just land it or crash it but still have the location. What really makes me a little mad is the fact it lost connection with full line of sight, in the mountains so no mag interference or anything like that. I just want to know why it had disconnected from my controller, when I was only really 2 miles away. Yes that is far but when the mavic says up to 4 miles it worries me about the safety I have flying. I do think the flying too far away was my fault but I don't believe it was my fault when it disconnected as it gave 0 warnings to me about it. One question, does the mavic still record data if it has GPS connection even if it's disconnected to the controller? thanks.

sar104 · Nov 20, 2017

According to the AirData analysis there were sustained winds from the west over 20 mph, and as high as 40 mph once you had the aircraft over 500 ft, blowing it away from you. And there were 16 high wind warnings during the flight that you apparently ignored. That was entirely pilot error.

ascho7 · Nov 20, 2017

sar104 said:
According to the AirData analysis there were sustained winds from the west over 20 mph, and as high as 40 mph once you had the aircraft over 500 ft, blowing it away from you. And there were 16 high wind warnings during the flight that you apparently ignored. That was entirely pilot error.

View attachment 25240

Yes, and I completely understand that. However, why did it disconnect from my controller? I understand the flyaway was my fault but what about the recovery? why did the mavic disconnect from my remote?

ascho7 · Nov 20, 2017

ascho7 said:
Yes, and I completely understand that. However, why did it disconnect from my controller? I understand the flyaway was my fault but what about the recovery? why did the mavic disconnect from my remote?

And as you can tell that as soon as it started to fly away I tried to return home because winds had gone from 10mph to 30 or so very quickly. I completely understand that it’s my fault but I mainly want to know why I had lost connection with the drone. It was a stupid day to fly it but I was feeling confident before my drone was just kind of taken by the wind. However, If the drone had landed where I had wanted it to, right by that road where the last signal was, I would’ve been able to recover it. Would the dat files give me any different last know signal information based off the fact the drone still had full gps?

sar104 · Nov 20, 2017

ascho7 said:
Yes, and I completely understand that. However, why did it disconnect from my controller? I understand the flyaway was my fault but what about the recovery? why did the mavic disconnect from my remote?

It lost connection because it was descending due to critically low battery, 2 miles away from you in hilly, forested terrain.

ascho7 · Nov 20, 2017

sar104 said:
It lost connection because it was descending due to critically low battery, 2 miles away from you in hilly, forested terrain.

View attachment 25241

View attachment 25242

However, I do believe I still had line of sight with it because I was at such a higher altitude and that’s what I don’t understand.

Hollow Dog · Nov 20, 2017

A 15m 00s -315.6 ft 9,753 ft Data Loss Downlink data connection lost for 1.4 seconds

Disconnect at -315.6 ft.
Just a guess, mavic was far below hilltops, in a valley area, landing from low battery.

I'm a local native, Boulder Co area is well known for high winds.

sar104 · Nov 20, 2017

ascho7 said:
And as you can tell that as soon as it started to fly away I tried to return home because winds had gone from 10mph to 30 or so very quickly. I completely understand that it’s my fault but I mainly want to know why I had lost connection with the drone. It was a stupid day to fly it but I was feeling confident before my drone was just kind of taken by the wind. However, If the drone had landed where I had wanted it to, right by that road where the last signal was, I would’ve been able to recover it. Would the dat files give me any different last know signal information based off the fact the drone still had full gps?

The DAT file on your mobile device won't have more position data than the txt log. The last known position is the one that you already have (39.9328, -105.3571), at around 500 ft AGL, moving east at around 10 mph and descending at around 2 m/s.

ascho7 · Nov 20, 2017

sar104 said:
The DAT file on your mobile device won't have more position data than the txt log. The last known position is the one that you already have (39.9328, -105.3571), at around 500 ft AGL, moving east at around 10 mph and descending at around 2 m/s.

So is there not another way to try and find where t actually landed? Even by having dji look at the files?

ascho7 · Nov 20, 2017

ascho7 said:
So is there not another way to try and find where t actually landed? Even by having dji look at the files?

Or in better words, is there any chance in hell I find my drone?

sar104 · Nov 20, 2017

ascho7 said:
So is there not another way to try and find where t actually landed? Even by having dji look at the files?

No - without the files from the aircraft, all you (or anyone else) can do is try to extrapolate from the last known location, based on terrain and wind speed, but, since we don't know the exact wind field as a function of position and altitude, that's a lot of guesswork. Since it was autolanding and the wind speed was dropping with decreasing altitude (as expected), I would look downwind (east) between the last recorded point mentioned above and a direct extrapolation of its final recorded descent path (which should be an overestimate of distance travelled) at 39.93242, -105.35456.

sar104 · Nov 20, 2017

ac0j · Nov 20, 2017

Sar gave you what you need, do the math and see if you can find the drone with the corrected landing area.

linuxglobal · Nov 20, 2017

ascho7 said:
Or in better words, is there any chance in **** I find my drone?

You will need to check the elevation when the signal was lost and calculate the projected travel. The drone list signal probably still in the air and got drifted as it landed.

You have to figure out your altitude at take off, that's the 0 point in elevation used as reference. Then extrapolate to when signal was lost.

Assuming you were about 500 feet above ground when signal was lost (152 meters), with a 10mph wind, you are looking at a drift of roughly 1085 feet from your last recorded location (typo corrected).

In the future, it would be best to land as soon as possible on a safe area where you do not lose signal and preserve battery life. Or Put the bird into SPORT mode to combat the wind flying against the wind at full speed while descending to keep it close to you. Not trying to be captain obvious, at this point you probably want to rescue it so you have some searching to do.

First step would be to figure out roughly what altitude it was at when it started to descend.

ascho7 · Nov 20, 2017

sar104 said:
No - without the files from the aircraft, all you (or anyone else) can do is try to extrapolate from the last known location, based on terrain and wind speed, but, since we don't know the exact wind field as a function of position and altitude, that's a lot of guesswork. Since it was autolanding and the wind speed was dropping with decreasing altitude (as expected), I would look downwind (east) between the last recorded point mentioned above and a direct extrapolation of its final recorded descent path (which should be an overestimate of distance travelled) at 39.93242, -105.35456.

Thank you very much for your help. It really does mean a lot to have such a good support team.