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Lost signal/drone
4818 37 2018-4-25
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djiuser_eyrzCuA1soHR
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Hello all,

I have an issue I’m hoping someone here may be able to advise on. There is a chance that the options I’ve been given are the only ones available but I do feel a bit let down by the support given.
I took my mavic air out to Lake Vrynwy a couple of weeks ago, it’s an absolutely beautiful place to see, especially from the air with a drone. I wanted to get some good shots of the dam, initially I did. I got the drone to pan from one side to the other, took a 200ft dronie and took some nice aeb shots. I wanted to get a close up shot of the dam and then get another reverse pan away shot of the whole dam. All was going great, I flew close enough for the sensors at the front to trigger, I know this is a risky move but I had faith in the drone as I have had a few months experience with drones. This is because I also have a Spark. The drone was situated below the take off level in front of me looking directly at the dam, it’s at this point the drone feed stopped to my phone. I can assure that there where no obstacles between the controller and the drone. I just assumed it was one of the random disconnects that occasionally happen and the signal would just come back, as it usually does. This want the case though, the signal just stopped! I watched the drone fly forward directly into the wall of the dam and crash into the waterfall. It’s safe to say that it is lost indefinitely. I have no idea as to how or why.

I have contacted support to raise an issue for this. I have synced my flight logs, attached the logs to emails and given a full description of my experience. There have been some quick replies initially and the logs have been looked into. The feedback I have got was that the logs show that I had full control of the drone right up until the end of the flight and as such there isn’t any warranty issue. I agree that the control was the during the entire log, it is however after the disconnection that the unusual behaviour happened. They have offered me a 30% discount on replacing the drone, battery, props and a memory card. This is an ok gesture from the supports side of things but I do feel like the responsibility has been avoided.

I responded to try and see if there where any logical aspects of the flight log they could take into account. The flight log clearly shows where the drone took off, the full flight I took and it’s final point before the signal stopped. The final point clearly shows that it was hovering below its take of altitude and the place where it was. These details show clearly that this isn’t the kind of place I would purposefully disconnect control of the drone myself and there is no logical reason why the I would want to end the flight in that place. However, this isn’t something that the support team are willing to take into account. I asked if there are any details on the logs to show reason as to how or why the control disconnected. The response I got was “As to your inquiries, we want to remind you that the remote connection of the aircraft can be interfered with by outside sources and invisible interference. Flying near any large amounts of concrete, steel, power lines, wifi technology, and other man-made sources can affect the behavior of the aircraft. The connection has been lost, which referred that the remote couldn't receive the signal of the aircraft, it was just like flashlight, under which situation you would not see the flashlight: 1) the light was blocked; 2) it was too far; 3) it ran out of power. So for your case, the aircraft wasn't far away and it had enough battery capacity, then the only reason could be that the connection between the aircraft and the remote was block by obstacles or invisible interference. This kind of interference affected the aircraft itself, but pilot might not detect it with eyes. That didn't mean any abnormalities or product malfunction.” The area didn’t have any phone signal, the nearest building that had any WiFi was around 400ft away and there was clear sight between the controller and the drone.

I’m posting this here for 2 reasons. First to see if there is any advice anybody could offer towards my situation and second to get my experience known by people, that way if others are in a similar situation they can also share the experience they had.




2018-4-25
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GDL
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Looks like my case. The log can’t show what happened after disconnected and hard to proof. Only you can find the plane and get the log inside to see what’s happening. I will check my MA with support to see what can they find.

https://forum.dji.com/thread-144319-1-1.html
2018-4-25
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Datadogie
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If you were as close to the dam as you say. Maybe the steel reinforcement in the concrete contributed to lost signal and possible compass settings.
2018-4-25
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djiuser_eyrzCuA1soHR
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Datadogie Posted at 2018-4-25 09:43
If you were as close to the dam as you say. Maybe the steel reinforcement in the concrete contributed to lost signal and possible compass settings.

You have a point there, just did some online checking for the build and it’s all stone built. Also, considering there where barely meters between the controller and the drone, would that have cut the signal out completely? Other thing is, the drone flew forward after disconnected, the sensors didn’t stop it and the RTH didn’t activate
2018-4-25
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Dacdiver
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If you lost signal should the drone have RTH?
2018-4-25
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Suren
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Sorry about the loss of your drone, we can only speculate what could have possible happened, if you have the flight log you could post it here so some of the experts can view it and maybe try to advise you on what transpired. I know that this might not help you right now but if you decide to get another drone you will know what happened and can avoid a similar issue. follow the instructions in the link below to get your log if you do not already have it and post the link here once uploaded.

http://www.phantomhelp.com/LogViewer/Upload/
2018-4-25
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hallmark007
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That’s all pretty tough, it can be tough in some situations like your one.

If you try looking at it from dji’s position, if they offer you a knew aircraft where there is no actual proof of what happened, then they are likely to have to do the same for everyone, if your AC just crashed and you had recovered it, then you would have proof as to what caused your crash, I suspect this is why your manual tells you not to fly over bodies of water.

There are also some holes in what you are saying and if you had your aircraft you would have had proof of what happened.
1/ you said aircraft flew straight a head and crashed. What should have happened is far removed from that.
Your aircraft on loosing signal should wait 3 seconds then climb to RTH height and fly home.
2/ you said that you flew to this location and OA worked and you hovered , it then took off straight , so presuming it was still in front of obstacle, it should not have moved, in order for it to have moved in a straight line there would have to have been a problem with automation or compass.

So in order to prove all of above you would certainly have had to produce log from drone itself, if you could have definitely proved that your craft malfunctioned like you said it did, I believe dji would have offered a warranty and new MavAir.

Unfortunately your phone log cut off when you lost signal, and craft was lost to the water. There would be nothing to stop dubious cases where others might make up similar stories, so my guess is they don’t want to leave themselves open, and this is a pity for those genuine cases where this happens.

I hope with your discount and the fact you still have RC that you can get a MavAir soon.
Good luck.
2018-4-25
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Marque Dragon
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Suren Posted at 2018-4-25 10:38
Sorry about the loss of your drone, we can only speculate what could have possible happened, if you have the flight log you could post it here so some of the experts can view it and maybe try to advise you on what transpired. I know that this might not help you right now but if you decide to get another drone you will know what happened and can avoid a similar issue. follow the instructions in the link below to get your log if you do not already have it and post the link here once uploaded.

http://www.phantomhelp.com/LogViewer/Upload/

That link is quite good, I’ll keep that. Interesting looking at it as the final part it shows the satellites dropped and the vps stated 16ft from ground. That seems strange for me as the drop is a lot further than that. If you know of any more info though, please tell. I appreciate any advise/help http://www.phantomhelp.com/LogViewer/1KC8XDLTWW6YW35KHSTC/
2018-4-25
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Suren
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Marque Dragon Posted at 2018-4-25 10:59
That link is quite good, I’ll keep that. Interesting looking at it as the final part it shows the satellites dropped and the vps stated 16ft from ground. That seems strange for me as the drop is a lot further than that. If you know of any more info though, please tell. I appreciate any advise/help http://www.phantomhelp.com/LogViewer/1KC8XDLTWW6YW35KHSTC/

Sorry I cannot help much with understanding these logs but as mentioned above an expert on this forum is bound to come around and assist.
2018-4-25
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Marque Dragon
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hallmark007 Posted at 2018-4-25 10:40
That’s all pretty tough, it can be tough in some situations like your one.

If you try looking at it from dji’s position, if they offer you a knew aircraft where there is no actual proof of what happened, then they are likely to have to do the same for everyone, if your AC just crashed and you had recovered it, then you would have proof as to what caused your crash, I suspect this is why your manual tells you not to fly over bodies of water.

Thanks, it is tough, it’s a lot to lose for me as I don’t exactly have a huge amount of spare money and it took me a few months to save. Initially I was saving for a pro but when the air released I decided to go with that as it looks nicer.

I do see it from a business aspect, the details I’ve given here are watered down to an extent but the main info is there. The drone fell a fair way and didn’t look like it would have made it in one piece. If I was able to send the drone for inspection, I certainly would have, alas this wasn’t an option as it’s underwater now. It was a risky move from my part but my faith in the drone was quite good at the time, I’ve used my spark a lot and felt confident in the mavic air more.
I would certainly like to get another mavic air, unfortunately the cost isn’t within my budget, even with 30% discount that had been offered.
2018-4-25
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Marque Dragon
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Suren Posted at 2018-4-25 11:10
Sorry I cannot help much with understanding these logs but as mentioned above an expert on this forum is bound to come around and assist.

Your help is much appreciated though. Thank you
2018-4-25
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Jack Beans
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Did you set your home point?  Did you put your phone on airplane mode?
2018-4-25
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Marque Dragon
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Jack Beans Posted at 2018-4-25 11:37
Did you set your home point?  Did you put your phone on airplane mode?

The home point was set, the phone wasn’t in airplane mode but all things where turned off, WiFi Bluetooth n such. Saying that though, might as well have put it in airplane mode as I didn’t have signal anyway.
2018-4-25
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hallmark007
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Marque Dragon Posted at 2018-4-25 10:59
That link is quite good, I’ll keep that. Interesting looking at it as the final part it shows the satellites dropped and the vps stated 16ft from ground. That seems strange for me as the drop is a lot further than that. If you know of any more info though, please tell. I appreciate any advise/help http://www.phantomhelp.com/LogViewer/1KC8XDLTWW6YW35KHSTC/

Looking at your log, it all makes a bit more sense.

1/ your altitude reading is from your homepoint is -16ft. VPS could not have been correct unless there was something sticking out from the drop and it got a reading from this.
2/ sudden gps loss from 16 sats to 6 sats at the end of your log, log calls it gentle gps real name weak gps

Weak gps probably caused by flying so close to bridge, and somehow blocking gps signal.

1/ your aircraft looks like it was loosing gps fast it dropped from 16 to 6, I would think this most likely dropped gps all together when you lost signal.
2/ if you lost gps or had extremely weak gps then this would account for your aircraft crashing into the bridge.
When gps is lost, you no longer have RTH , Your aircraft will go to Atti mode you will also not have obstacle avoidance , and your aircraft will move horizontally by itself as it has no gps lock.
So for me this would explain no action to RTH no OA and the sudden move forward to crash into bridge
2018-4-25
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Marque Dragon
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hallmark007 Posted at 2018-4-25 11:42
Looking at your log, it all makes a bit more sense.

1/ your altitude reading is from your homepoint is -16ft. VPS could not have been correct unless there was something sticking out from the drop and it got a reading from this.

It does help, like I said, I’m saving that link as I think it will come in useful.

I’m intrigued by he sudden drop, as that was the second time I flew closer to the dam/bridge, the first being just before I did the dronie shot. There wasn’t any structure sticking out, it was an incline though and possibly that’s what it picked up but couldn’t say for sure.

Thank you for the feedback.
2018-4-25
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GDL
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Fly drone below you need to be very careful as it doesn’t designed to receive signal from above. Close to large object also may block signal. Especially below bridge or in closed area.
2018-4-25
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Marque Dragon
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GDL Posted at 2018-4-25 19:12
Fly drone below you need to be very careful as it doesn’t designed to receive signal from above. Close to large object also may block signal. Especially below bridge or in closed area.

True, that circumstance though the flight was still quite high relatively. It wasn’t below the bridge, just in front of it so that would leave 5 angles of wide ope space, that’s if you include below the drone. I have done similar flights with my spark, this is why I felt confident that I would be fine. The more I look at the details the better informed I am about it.

It is possible that a combination of quite a few different things happened in order to make the situation but that is just speculation and there is just as much chance that the drone may have faulted.
2018-4-25
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GDL
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Problem is you can’t proof the drone is faulted without recovering it for checking.
2018-4-25
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Marque Dragon
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GDL Posted at 2018-4-25 21:47
Problem is you can’t proof the drone is faulted without recovering it for checking.

I know
2018-4-25
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Kevjones1959
Second Officer
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South Africa
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I still dont understand why the drone flew "forward" on it's own.
2018-4-25
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JJBspark
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hallmark007 Posted at 2018-4-25 11:42
Looking at your log, it all makes a bit more sense.

1/ your altitude reading is from your homepoint is -16ft. VPS could not have been correct unless there was something sticking out from the drop and it got a reading from this.

HIya,

I think that GentleGPS is shown on the mobile device when APAS is selected.
Why do i think that, did some testing and switching to APAS shows GentleGPS.

cheers
JJB
2018-4-26
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hallmark007
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JJBspark Posted at 2018-4-26 01:46
HIya,

I think that GentleGPS is shown on the mobile device when APAS is selected.

Thanks jjb was confused about that .
2018-4-26
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Marque Dragon
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Kevjones1959 Posted at 2018-4-25 23:37
I still dont understand why the drone flew "forward" on it's own.

I’m not 100% on that either but I think the explanation of the gps satellites signal dropping causes atti mode in which may have caused it to not keep its fixed position. I’m learning a lot more about these quirks by the day since this happened.
2018-4-26
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Marque Dragon
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Kevjones1959 Posted at 2018-4-25 23:37
I still dont understand why the drone flew "forward" on it's own.

I’m not too sure on this either. hallmark007 on post #14 suggested something that makes sense though. I’m not an expert, all I have is what I saw it do
2018-4-26
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Kevjones1959
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South Africa
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Right why did it lose GPS signal unless you flew under something.
2018-4-26
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Marque Dragon
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Kevjones1959 Posted at 2018-4-26 08:24
Right why did it lose GPS signal unless you flew under something.

That is a good question, doesn’t have an answer though as the logs ended when the signal dropped. I feel there was a fault but this is where the debate with the tech support team is at. Because the logs don’t have a definitive error logged they deny there would have been a fault.
2018-4-26
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Kevjones1959
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Marque Dragon Posted at 2018-4-26 08:39
That is a good question, doesn’t have an answer though as the logs ended when the signal dropped. I feel there was a fault but this is where the debate with the tech support team is at. Because the logs don’t have a definitive error logged they deny there would have been a fault.

I am sure if you search through the posts there are other examples of the GPS signal being lost for no apparent reason. Loss of GPS has nothing to do with steel or other forms of interference as I understand it.
2018-4-26
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DJI Susan
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Hey Marque, I managed to get the case number via the forum info. Please kindly find the data analysis result as below:

1. The aircraft was in GPS mode;
2. T=08:23, H=-4.6 m, D=25.6 m, the aircraft flew forward at 0.9 m/s after the pilot pushed the Elevator forward, then the app record ended;

Just from the flight records, I'm afraid that it is really hard to tell the exact status after the flight record ended, so the conclusion is inconclusive. Sorry about this. I understand your feeling, and will forward this to the Management for further follow-up. Appreciate your understanding and patience.

2018-4-26
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Marque Dragon
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DJI Susan Posted at 2018-4-26 20:33
Hey Marque, I managed to get the case number via the forum info. Please kindly find the data analysis result as below:

1. The aircraft was in GPS mode;

Thank you for the reply.

If it’s any help, I have replied to the emails thread with some additional logs from that day. The additional information shows a flight with my Spark. In this log it has the drone flying in the same area and is within feet of where the Mavic disconnected, however the connection to controller and gps is all great with no hitches.im thinking that this can show there is less likely to be any other external interference that contributed to the incident.
2018-4-26
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DJI Susan
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Marque Dragon Posted at 2018-4-26 21:38
Thank you for the reply.

If it’s any help, I have replied to the emails thread with some additional logs from that day. The additional information shows a flight with my Spark. In this log it has the drone flying in the same area and is within feet of where the Mavic disconnected, however the connection to controller and gps is all great with no hitches.im thinking that this can show there is less likely to be any other external interference that contributed to the incident.

The Mavic Air has been lost, so the flight log cannot be offered to confirm what happened after that. The malfunction you mentioned cannot be verified on another drone, please kindly note. Thanks for your understanding.
2018-4-28
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Marque Dragon
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DJI Susan Posted at 2018-4-28 03:33
The Mavic Air has been lost, so the flight log cannot be offered to confirm what happened after that. The malfunction you mentioned cannot be verified on another drone, please kindly note. Thanks for your understanding.

Of course it’s not going to prove there was a fault.

As you stated yourself, the evidence you had was inconclusive. In that case you have decided that it wasn’t a warranty issue and that the only help you would be willing to give is a 30% discount on a replacement. As I’ve stated before, I do appreciate the offer and don’t dispute that it shows a good gesture. I do however dispute that even though the evidence is inconclusive that you state it isn’t a fault that occurred. I asked for a reason that the disconnection occurred and the reply was “invisible interference” this additional log is from another DJI device that is likely to be susceptible to the same “invisible interference” and shows that this isn’t likely to be a factor.

I do understand that from a profitable company point of view that you have a very clear black and white guidance to follow and are most likely in a position to try and reduce the cost from your part and increase any income.

I would however like a genuine understanding from you about my issue with this. I am left in a position where I have lost a great deal of money that I worked for some time to save. Although to you these words are most likely to be like a tear drop in the ocean.
2018-4-28
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DJI Mindy
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Marque Dragon Posted at 2018-4-28 04:55
Of course it’s not going to prove there was a fault.

As you stated yourself, the evidence you had was inconclusive. In that case you have decided that it wasn’t a warranty issue and that the only help you would be willing to give is a 30% discount on a replacement. As I’ve stated before, I do appreciate the offer and don’t dispute that it shows a good gesture. I do however dispute that even though the evidence is inconclusive that you state it isn’t a fault that occurred. I asked for a reason that the disconnection occurred and the reply was “invisible interference” this additional log is from another DJI device that is likely to be susceptible to the same “invisible interference” and shows that this isn’t likely to be a factor.

Marque, Susan has escalated your case to the appropriate department to see if there is better resolution can be provided, we will have someone to contact you in working hours, please wait patiently, thank you.
2018-4-29
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Marque Dragon
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DJI Mindy Posted at 2018-4-29 02:48
Marque, Susan has escalated your case to the appropriate department to see if there is better resolution can be provided, we will have someone to contact you in working hours, please wait patiently, thank you.

The further help offered is exactly the same, just phrased slightly differently.
I essence, the person who is “helping” my case is only willing to take account the one log that shows no error but still eludes the fact that there was behaviour the drone took that isn’t what is supposed to happen. I keep getting the reply saying that as this log looks they cannot prove whether this is a fault or not.
Am I being unreasonable by asking them prove it wasn’t a fault? They can’t! Essentially the result/outcome is 50/50 the resolution/fix is 70/30 in favour of DJI!
2018-5-2
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Marque Dragon
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Additional, I have now been advised that I don’t have a right to answers based on the fact that there isn’t a warranty issue! Also I am trying to trick them into giving me warranty! I’m curious if the Supervisor support are teenagers and are incapable of answering a question!
2018-5-3
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DJI Mindy
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Marque Dragon Posted at 2018-5-3 09:59
Additional, I have now been advised that I don’t have a right to answers based on the fact that there isn’t a warranty issue! Also I am trying to trick them into giving me warranty! I’m curious if the Supervisor support are teenagers and are incapable of answering a question!

Marque, we also would like to figure out what caused the accident, but according to the remaining flight records, the result is inconclusive, in this situation, we could only provide the 30% off discount for another one, our supervisor team has made the final decision, hope you can understand.
2018-5-3
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Milos Vegano Stepita
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I lost my drone last week because of signal loss as well. I was flying around the peak of the mountain and when I was behind the connection got lost. I tried to fly up but the numbers on the controller stayed the same so the drone stayed at the same place. So I could not control the drone at all, the only option was to automatically land, which could have been on the steep cliff or even the sea or to press Return home button. I thought woth Return home the drone should avoid the obstacles and fly above the peak. After pressung Return home the signsl was still lost and then suddenly the transmission got back on. The last seconds I just saw the drone flying straight into the cliff, crashing into the rocks and falling who knows how much down. Why the hell were the obstacle sensors disabled when I couldn’t control the drone. I was absolutelly outraged, I bet many people will loose their drones this way.
2019-10-6
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Milos Vegano Stepita
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Dacdiver Posted at 2018-4-25 09:57
If you lost signal should the drone have RTH?

RTH didn’t sense obstacles in my case
2019-10-6
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DJI Mindy
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Milos Vegano Stepita Posted at 10-6 23:20
I lost my drone last week because of signal loss as well. I was flying around the peak of the mountain and when I was behind the connection got lost. I tried to fly up but the numbers on the controller stayed the same so the drone stayed at the same place. So I could not control the drone at all, the only option was to automatically land, which could have been on the steep cliff or even the sea or to press Return home button. I thought woth Return home the drone should avoid the obstacles and fly above the peak. After pressung Return home the signsl was still lost and then suddenly the transmission got back on. The last seconds I just saw the drone flying straight into the cliff, crashing into the rocks and falling who knows how much down. Why the hell were the obstacle sensors disabled when I couldn’t control the drone. I was absolutelly outraged, I bet many people will loose their drones this way.

Hi Milos Vegano Stepita, we are sorry for your loss, if the drone is still under warranty, please contact our support team www.dji.com/support to start a ticket for the data analysis, we will help figure out what happened and provide the proper resolution.
2019-10-7
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