Lost Mavic after loss of connection

[Oli34]

After checking that the aircraft was safe to fly, I took off from a carpark that over looked Polzeath (Cornwall UK). The signal was excellent when I started to take photos and videos of the sunset when suddenly the remote said connection lost. I then immediately pressed return to home but the drone didn’t respond. I ran to the cliff edge as it was Lowtide I went onto the beach to search for the drone at its last known location . I searched everywhere for an hour, and had the controller on at all time. I asked people on the beach if I had seen the drone but no one had. I had taken all precautions and always kept the drone in line of sight as instructed by the app.

I’ve sent data to DJI. I’m hoping for a claim on the warranty as I was very close to the drone given it’s meant to have a huge range.

What do you guys think about this case?

 

[Meta4]

After checking that the aircraft was safe to fly, I took off from a carpark that over looked Polzeath (Cornwall UK). The signal was excellent when I started to take photos and videos of the sunset when suddenly the remote said connection lost. I then immediately pressed return to home but the drone didn’t respond. I ran to the cliff edge as it was Lowtide I went onto the beach to search for the drone at its last known location . I searched everywhere for an hour, and had the controller on at all time. I asked people on the beach if I had seen the drone but no one had. I had taken all precautions and always kept the drone in line of sight as instructed by the app.

I’ve sent data to DJI. I’m hoping for a claim on the warranty as I was very close to the drone given it’s meant to have a huge range.

What do you guys think about this case?

I'm thinking that there isn't enough information for anyone to be able to come up with reasonable suggestions.
As always, recorded flight data is what's needed to have a chance of working out the issue., although that can be difficult when signal is lost.
But it still might have some clues.
To see what the data says, g
Go to DJI Flight Log Viewer - Phantom Help
Follow the instructions there to upload your flight record from your phone or tablet.
Come back and post a link to the report it gives you.

And if you had your drone in sight, can you say what happened to the drone when you lost connection?

I wouldn't count on DJI coming to the party.
They would need to have proof of a DJI problem, not just a lost drone.

 

[Oli34]

Thank you.
Although I sent the data via the app DJI wat me to go to iTunes and use drop box which I’m doing.

I was looking at the drone but then the controller bleeped saying loss of connection. I looked down at the controller to see what was going on. After looking bask at the drone it had vanished...

 

[Meta4]

Thank you.
Although I sent the data via the app DJI wat me to go to iTunes and use drop box which I’m doing.

I was looking at the drone but then the controller bleeped saying loss of connection. I looked down at the controller to see what was going on. After looking bask at the drone it had vanished...

DJI aren't very good at communication.
If you want some ideas on the possible cause of the incident, you'd need to post a link to the flight data here.

How far away was the drone?
Should you have been able to see it if it was there?
Was it over the sea at the time?

There are two possibilities.
Either:
1. You lost connection and for some reason the drone did not return to home as it is programmed to. or
2. The drone suffered a sudden power loss and fell out of the sky and the loss of connection was due to this.

 

[Oli34]

697ft away. The drone was at a height that I could see. The was a building between the street and I but I ensured that there was no obstacles between the controller and the drone.

It had 97% battery at time of the loss of signal and the drone did not return to home...

There must have been a malfunction. All software was up to date.

 

[Oli34]

697ft away. The drone was at a height that I could see. The was a building between the street and I but I ensured that there was no obstacles between the controller and the drone.

It had 97% battery at time of the loss of signal and the drone did not return to home...

There must have been a malfunction. All software was up to date.

It was over the edge of the sea as it was low tide as shown in satellite pic

 

[4wd]

With a lost connection, pressing RTH wouldn't do anything, but it should return to the last marked home point after a few seconds anyway.
The log will show if homepoint was set correctly.
Perhaps a seagull hit it, flying away randomly is vanishingly rare, but it's very hard to see again if you look away for a moment.
Again the log might show sudden upset and/or falling

 

[Oli34]

Thank you for your advice. One final question. Is the log different in iTunes than on the app because I’ve synced the app to DJI. They want me to go through itunes

 

[Simmo]

You can follow the instructions given to you above, to show up the TXT file.
Seemingly DJI are asking for the .DAT file, which is large, and needs to go to dropbox or similar.
Post both the links back here and people can give you their opinion as well as DJI's..

 

[Oli34]

Dropbox - DJIFlightRecord_2018-10-18_[17-49-10].txt

Dropbox - DJIFlightRecord_2018-10-17_[18-56-27].txt

 

[sar104]

Dropbox - DJIFlightRecord_2018-10-18_[17-49-10].txt

Dropbox - DJIFlightRecord_2018-10-17_[18-56-27].txt

The log file doesn't show any problems, up to the point where it just stops. There were no indications of signal interruption. The winds at 85 m were ~ 15 mph out of the north east - well within the aircrafts capabilities. The signal loss was very sudden and I haven't seen any reports of that happening due to the iOS GO app, so it was likely either a battery disconnect or an FC shutdown that appears to be an uncommon but established problem with the Mavic 2. In that case it should have fallen out of the sky and be between 10 and 20 meters southwest of the last recorded location:



50.578409° N, 4.919373° W.

 

[Oli34]

Thank you. DJI have a lot to answer for and it sounds like a possible warranty case!

 

[sar104]

Thank you. DJI have a lot to answer for and it sounds like a possible warranty case!

Possibly. But without the aircraft they may not be able to determine cause definitively. It will be interesting to see how they respond.

 

[deleted member 877]

From reading various threads regarding such topics as "flying over water" and "lost drones" it is evident that a certain amount of risk will always be present when flying our drones. Though very comprehensive and sophisticated, the DJi hardware/software/firmware components are no different to the rest of the tech industry in that they will never be 100% reliable.

The best we can do is to regularly calibrate the compass and sensors and, as previously mentioned, take a careful inventory of the geographical environment and weather conditions prior to launch. Also, ensure that the "Return to Home on Lost Signal" setting is always activated.

If for whatever reasons erratic flight behaviour has previously occurred when flying over water, it's probably a good idea to deactivate the downward facing sensors at least to determine if this resolves the issue.

 

[rfc]

If for whatever reasons erratic flight behaviour has previously occurred when flying over water, it's probably a good idea to deactivate the downward facing sensors at least to determine if this resolves the issue.

That's all well and good, but this thread, and several other recent Mavic 2 threads seem to point to some unknown problem causing a sudden battery disconnect or FC shutdown. Downward sensors at the altitude this M2 was at, play virtually no roll whatsoever.

As an M2P owner though, until it becomes clearer what's causing these similar occurrences, it sure makes me nervous to needlessly fly over water, for the simple reason that you can't easily get DJI to replace the A/C after such an incident without the A/C.

 

[Meta4]

From reading various threads regarding such topics as "flying over water" and "lost drones" it is evident that a certain amount of risk will always be present when flying our drones. Though very comprehensive and sophisticated, the DJi hardware/software/firmware components are no different to the rest of the tech industry in that they will never be 100% reliable.

The sudden power loss incidents are noteworthy but are quite rare, only affecting a tiny percentage of the drones out there.
Mavics lost due to operator disorientation or mistake such as flying into trees, wires, buildings etc, flying behind obstacles, flying downwind in a strong wind and not able to get back, launching from reinforced concrete etc is probably 20 times more.

The best we can do is to regularly calibrate the compass and sensors and, as previously mentioned, take a careful inventory of the geographical environment and weather conditions prior to launch. Also, ensure that the "Return to Home on Lost Signal" setting is always activated.

Return to Home is the default action for loss of signal and will never change unless you change it.
The compass and sensors do not need regular calibration.
If your drone hovers in place without slowly spiraling and flies straight, leave it alone.

 

[deleted member 877]

The sudden power loss incidents are noteworthy but are quite rare, only affecting a tiny percentage of the drones out there.
Mavics lost due to operator disorientation or mistake such as flying into trees, wires, buildings etc, flying behind obstacles, flying downwind in a strong wind and not able to get back, launching from reinforced concrete etc is probably 20 times more.

Return to Home is the default action for loss of signal and will never change unless you change it.
The compass and sensors do not need regular calibration.
If your drone hovers in place without slowly spiraling and flies straight, leave it alone.

It certainly does not hurt to regularly calibrate the compass and sensors regardless of whether or not the drone hovers nicely in place and you really shouldn't have 100% confidence in what is indicated on screen in regard to compass/sensor status. It's all about being able to rule out potential contributing factors when things go wrong.

I am aware that RTH is the default action for loss of signal but it's also possible to inadvertently change that and other settings, so it's always worth checking as part of the pre-flight routine. Before launching the hang glider I always check everything regardless of whether or not it's something that can be adjusted - it's my life that I am protecting, the same as for any other pilot who visually checks the aircraft's control surfaces prior to take-off.

OK so, unless a UAV pilot is breaking the rules, there is little or no risk to human life but that doesn't mean that thorough pre-flight checks should not be performed before every flying session. But if you don't really care about losing or damaging your drone then just turn on and go. It's only money, right?

 

[Meta4]

It certainly does not hurt to regularly calibrate the compass and sensors regardless of whether or not the drone hovers nicely in place and you really shouldn't have 100% confidence in what is indicated on screen in regard to compass/sensor status. It's all about being able to rule out potential contributing factors when things go wrong.

It doesn't help either.
The compass doesn't lose calibration.
People that advocate frequent recalibration of the compass do it because they don't understand what calibrating the compass actually does.
If your compass has a problem, you will know it.

 

[deleted member 877]

It doesn't help either.
The compass doesn't lose calibration.
People that advocate frequent recalibration of the compass do it because they don't understand what calibrating the compass actually does.
If your compass has a problem, you will know it.

Why would you assume that I don't understand what calibrating the compass actually does? Do the research - you'll find more than one experienced UAV pilot who agrees with my suggestion.

 

[DanMan32]

Not only that but you can take an otherwise excellent factory calibration and make it less accurate. Take IMU. You can put it on a perfectly level surface to start, but some of the required positions don't have the AC sit solid in only one possible angle, nor does the app wait for you to tell it you have finished moving it to its subsequent position. Hopefully it doesn't have a tight tolerance.
For vision sensor calibration, you're not supposed to move it from side to side but we're not machines so wander is inevitable and may contribute to undetected calibration error.
Compass might be calibrated against an undetected magnetic / metallic interference, thus throwing the compass off without knowing it.

Can the logs confirm fail-safe was set to RTH and not hover or *gasp* LAND? It's unlikely but still possible.

It's not uncommon to get less than a mile range due to radio interference in the environment but 600ft shouldn't lose signal, unless a large object such as a thick tree or building was in line between the RC and AC.