Drone disconnects and flyaway

[ascho7]

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 1085m (3560 feet) from your last recorded location.
So if you had an east wind, search 3500 feet east away from your last point.

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.

Thanks, one question, how do I switch to sport mode? I tried hitting the switch and it said I can't change it mid flight. Also, thank you very much for being so helpful in teaching me how to find the extrapolated landing.

 

[linuxglobal]

Thanks, one question, how do I switch to sport mode? I tried hitting the switch and it said I can't change it mid flight. Also, thank you very much for being so helpful in teaching me how to find the extrapolated landing.

I dont have the remote near me now, but I believe the app has a setting to enable multiple flight modes, It has a few warnings associated with it before it allows it to take place.

Once the multiple flight modes are enabled you will be able to engage sport mode on the side of the controller while in flight (sensors will be disabled in sport mode).

See link below on how to enable SPORT Mode.

Can't engage Sport Mode

Hopefully you can find the bird, I have fixed a few of these bad boys so always out here to lend advice and a helping hand to get it up and going again.

 

[ascho7]

Thank you so much it really does mean a lot I’m hoping I find it too because I saved a whole year for it

 

[sar104]

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 1085m (3560 feet) from your last recorded location.
So if you had an east wind, search 3500 feet east away from your last point.

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.

1085 m looks like an overestimate to me, although you did not state the descent rate that you assumed for the calculation. At the end of the flight it was actually descending steadily at 3 m/s, and so it would descend 150 m in 50 seconds. In a 10 mph wind (4.5 m/s) it would drift 225 m (740 ft).

 

[ascho7]

1085 m looks like an overestimate to me, although you did not state the descent rate that you assumed for the calculation. At the end of the flight it was actually descending steadily at 3 m/s, and so it would descend 150 m in 50 seconds. In a 10 mph wind (4.5 m/s) it would drift 225 m (740 ft).

Sar, do you believe it would stay along that same line that it was going on?

 

[linuxglobal]

1085 m looks like an overestimate to me, although you did not state the descent rate that you assumed for the calculation. At the end of the flight it was actually descending steadily at 3 m/s, and so it would descend 150 m in 50 seconds. In a 10 mph wind (4.5 m/s) it would drift 225 m (740 ft).

Assumed 2m/s descend due to lateral drift slowing down descend rate, gives it 76 seconds to land. That equates to roughly 342 m lateral travel (1122 feet).
If its 3m descend, then yes it would be at your estimate, either way its a bit of a foot travel to find it.

 

[Qoncussion]

ascho7 ~ so sorry for your loss. I really hope the information here helps you find it! I know this comment is slightly off to the side of this conversation, but worth a mention for anyone else learning about how to safely ditch a Mavic when all other options have been exhausted. Especially in the mountains, when you realize that you need to land wherever you currently are ~ it is a really good idea to set the Mavic to either hover or land when it loses signal. As you descend into the treeline, even with the perfect landing spot selected through the video feed, and especially at the distance you were from your home point in a high wind environment, if you lose your transmission signal, you don't want the craft initiating a RTH.

Just my $0.02 ~ I really hope you find your craft!

 

[ascho7]

ascho7 ~ so sorry for your loss. I really hope the information here helps you find it! I know this comment is slightly off to the side of this conversation, but worth a mention for anyone else learning about how to safely ditch a Mavic when all other options have been exhausted. Especially in the mountains, when you realize that you need to land wherever you currently are ~ it is a really good idea to set the Mavic to either hover or land when it loses signal. As you descend into the treeline, even with the perfect landing spot selected through the video feed, and especially at the distance you were from your home point in a high wind environment, if you lose your transmission signal, you don't want the craft initiating a RTH.

Just my $0.02 ~ I really hope you find your craft!

Thank you, but the only problem was it was landing... you probably know more than I do but that was the problem. The battery was low enough to land automatically however with the loss of connection I didn't have the final landing point and or crashing point.

 

[sar104]

Assumed 2m/s descend due to lateral drift slowing down descend rate, gives it 76 seconds to land. That equates to roughly 342 m lateral travel (1122 feet).
If its 3m descend, then yes it would be at your estimate, either way its a bit of a foot travel to find it.

Agreed - so maybe you mixed up feet and meters - you wrote "1085 m (3560 feet)".

 

[sar104]

Sar, do you believe it would stay along that same line that it was going on?

I think a reasonable assumption is that the wind direction was roughly constant, but I would expect that the wind speed will decrease with decreasing altitude (as indicated by AirData). So direction of travel during descent should stay the same, but speed will decrease. That's why assuming constant lateral speed should give a conservatively high estimate of how far it may have gone.

Note that you can also approximate the result pretty well in Google Earth by plotting the flight path, then while sighting down the descent path place a marker on the ground. If you the change to a vertical view you can see the extra distance travelled. That method also takes into account terrain variation down range of the last recorded point. The two images below illustrate the method. In this case the intersect with the ground is 165 m beyond the last recorded point.

 

[ascho7]

I think a reasonable assumption is that the wind direction was roughly constant, but I would expect that the wind speed will decrease with decreasing altitude (as indicated by AirData). So direction of travel during descent should stay the same, but speed will decrease. That's why assuming constant lateral speed should give a conservatively high estimate of how far it may have gone.

Note that you can also approximate the result pretty well in Google Earth by plotting the flight path, then while sighting down the descent path place a marker on the ground. If you the change to a vertical view you can see the extra distance travelled. That method also takes into account terrain variation down range of the last recorded point. The two images below illustrate the method. In this case the intersect with the ground is 165 m beyond the last recorded point.

View attachment 25248

View attachment 25249

Wow, thanks for the detailed approach to my question. I am waiting to hear back from DJI about it as it is a little bit of a haul to go back to the site. Thank you so so much though for helping me with this.

 

[rolling56]

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.

hmmm line of sight means you are looking at it physically. Not looking in the direction of where you think it is.

 

[ascho7]

hmmm line of sight means you are looking at it physically. Not looking in the direction of where you think it is.

Ohhhh whoops sorry about that what I mean was there was a line with no interferences to where the drone was

 

[ascho7]

Given said all of this, do you think DJI will atleast give 30% Discount, maybe even something more? The only problem is that I spent a year trying to earn enough money for this and I'm not sure how long it will take to earn enough money for a new one. If any of you have any ideas, let me know. I still want to search for it but even with that good of an estimation I don't know if I will be able to find it, as it is an estimation.

 

[sar104]

Given said all of this, do you think DJI will atleast give 30% Discount, maybe even something more? The only problem is that I spent a year trying to earn enough money for this and I'm not sure how long it will take to earn enough money for a new one. If any of you have any ideas, let me know. I still want to search for it but even with that good of an estimation I don't know if I will be able to find it, as it is an estimation.

It's certainly worth asking but I think it is unlikely because there is no evidence of any problem with the aircraft. In other cases where they have offered discounts there has often been some kind of error (mostly compass errors triggering ATTI mode) that may not have caused the crash but contributed to the pilot failing to bring it back. In this case there were no sensor or power issues at all, and no signal problems until the final descent phase 2 miles away.

I would definitely go back and look for the aircraft if you can, because the estimated area is relatively small. I'd walk the line from the last recorded point to the estimated point that I posted earlier. That's only a couple of hundred meters. Then check 50 m either side of that line if necessary.

 

[ascho7]

It's certainly worth asking but I think it is unlikely because there is no evidence of any problem with the aircraft. In other cases where they have offered discounts there has often been some kind of error (mostly compass errors triggering ATTI mode) that may not have caused the crash but contributed to the pilot failing to bring it back. In this case there were no sensor or power issues at all, and no signal problems until the final descent phase 2 miles away.

I would definitely go back and look for the aircraft if you can, because the estimated area is relatively small. I'd walk the line from the last recorded point to the estimated point that I posted earlier. That's only a couple of hundred meters. Then check 50 m either side of that line if necessary.

Taking your advice, I’m going to look Thursday as it is the first day i will have the chance to go look. Do you have any other things that I can do to try and help in finding the drone? Otherwise thank you so much for your help.

 

[sar104]

Taking your advice, I’m going to look Thursday as it is the first day i will have the chance to go look. Do you have any other things that I can do to try and help in finding the drone? Otherwise thank you so much for your help.

I'd hike up from the dirt road following the fligth path, and onwards under the extension of it. It looks like mixed conifer (ponderosa, blue spruce etc.) so you will probably have to hope that it made it to the ground. Rather harder to spot than a Phantom, unfortunately.

 

[FearlessRobb]

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?

That's someone stated before you were in ATT mode I believe I'm not a hundred percent sure on this but I don't think return the homework's in that mode but if it does you said that it went from 10 to 30 miles per hour wind max speed on return home I believe the Drone goes to only 20 to 25 miles an hour so the wind could have been pushing it further and further away from you to the point where your drone disconnected and I couldn't return home because the winds were so powerful that's just my thought though

 

[FearlessRobb]

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.

The Drone says up to four miles but that's in like perfect condition if you run the battery as low as it can possibly go and there is no return home for that if you go 4 miles if your two miles out the lower you go the last reception you get one tree in between you and the Drone can cause a milamore difference in signal

 

[sar104]

That's someone stated before you were in ATT mode I believe I'm not a hundred percent sure on this but I don't think return the homework's in that mode but if it does you said that it went from 10 to 30 miles per hour wind max speed on return home I believe the Drone goes to only 20 to 25 miles an hour so the wind could have been pushing it further and further away from you to the point where your drone disconnected and I couldn't return home because the winds were so powerful that's just my thought though

It wasn't in ATTI mode.