Lost signal and lost M2P

[dm166]

Hi everyone, this is the first one I write here unfortunately due to an accident. I've been despairing for days without finding a solution! I hope some of you are kind enough to give me some advice!
I am or rather I was a mavic 2 pro owner, I was flying and everything went perfectly, as I also verified from the logs, when at a certain point the mavic suddenly lost the signal without even giving me a weak signal warning! I was not worried when I lost the signal because I was confident in an RTH also because the drone was 180 meters above the highest obstacle. The problem is that the mavic has never done any RTH. I waited a long time and when I realized that the drone was no longer returning, without turning off the radio control, I moved to favorable positions to resume the signal but this has no longer happened. It is as if he died at some point without having more news! Do any of you have any idea what could have happened? I have been looking for mavic for days but without being able to find it! I have already contacted DJI support which, unfortunately, if I can't find the drone, they can't cover me under warranty. They only offered me a discount! thank you all in advance, I hope to solve the problem thanks to your help. I'm really desperate

 

[Fly Dawg]

I also verified from the logs, when at a certain point the mavic suddenly lost the signal without even giving me a weak signal warning! I was not worried when I lost the signal because I was confident in an RTH also because the drone was 180 meters above the highest obstacle.

Can you share the logs? Both the .txt and .dat. We may be able to a bit of detailed looking to see what happened, and possibly calculate a location.

 

[Camino Ken]

Sorry for your loss. Posting your logs as mentioned above is your best chance to figure out what happened and where it might be.

 

[dm166]

nel frattempo, grazie per la Risposta! scusa per la mia inesperienza. Non ho un pc qui con me in questo momento. Ho caricato i log su airdata e registrato a dji ma se ricordo correttamente sono solo .txt dove trovo .dat? posso condividere il link airdata nel frattempo? Puoi aiutare?

Translation from Italian;
in the meantime, thanks for the Answer! sorry for my inexperience. I don't have a pc here with me right now. I uploaded the logs on airdata and registered to dji but if I remember correctly they are only .txt where do I find .dat? can I share the airdata link in the meantime? You can help?

 

[Meta4]

Do any of you have any idea what could have happened?

The first step is always to look into the recorded flight data to see if it has some clues.

Go to DJI Flight Log Viewer | Phantom Help
Follow the instructions there to upload your flight record from your phone or tablet.
That will give you a detailed report on the flight data.
Come back and post a link to the report it gives you.

Or just post the .txt file here.

 

[Fly Dawg]

@dm166 Yes, you can share the Airdata. Make sure you make it fully sharable such that we can recover the original file.

 

[Fly Dawg]

@dm166....

Il primo passo è sempre quello di esaminare i dati di volo registrati per vedere se ha qualche indizio.

Vai a DJI Flight Log Viewer | Phantom Help
Segui le istruzioni lì per caricare il tuo record di volo dal tuo telefono o tablet.
Ciò ti fornirà un rapporto dettagliato sui dati di volo.
Torna e pubblica un link al rapporto che ti dà.

Oppure pubblica qui il file .txt.

Questo è da Post # 5

 

[dm166]

hello everyone thanks again for the help and sorry I'm late, but yesterday I didn't have a PC with me.
I am attaching the .txt files taken from the flightrecords folder. unfortunately the MCDatFlightRecords folder is empty, I don't understand why. I hope someone can enlighten me, it's all very strange that it can only be a malfunction of M2P. thanks again i can't wait to hear from you.

 

[Thomas B]

Just a quick reminder that the official language of the forum, per posted rules, is English.

Google Translate can be a great help. @dm166 original post was English.

dm166 Best of luck in getting your question answered.

 

[dm166]

hello Thomas excuse me, I had written in English but the translator translated automatically.
Thank you

 

[Meta4]

at a certain point the mavic suddenly lost the signal without even giving me a weak signal warning!

Your flight data looks like this: DJI Flight Log Viewer - PhantomHelp.com
The usual reasons for a drone failing to return are:

1. Being blown away or not being able to fight a strong headwind
2. Running out of battery
3. RTH path blocked by an obstacle

1. You were quite high and strong winds are often a problem at high altitudes.
But when I check the data, from 5:59.8 to 6:18.5, the drone was at 945 ft altitude with the sticks centred.
Speed remains at zero, indicating that the wind up there was not too strong for the drone to return against.

2. At the end of the flight data, the battery was at 67% at a distance of 1700 metres.
It should have easily been able to return.

3. The drone was too high for obstacles to be a concern.

Something I notice is that the Failsafe Action which is usually set to the default value (RTH) has been changed to Land.
If the drone lost signal, the drone would not have returned at all.
Instead it would have landed where signal was lost.

That leaves two possible causes for the loss of the drone:
1. Signal was lost and the drone autolanded a little to the NW of 37.78005 14.60728
2. There was a sudden loss of power and the drone crashed a little to the NW of 37.78005 14.60728

 

[dm166]

hello Meta4 thanks for the reply, very kind! I can't understand where we see that the failsafe action is set in land? I'm sure the failsafe is set to RTH. Also why would he find it further north-west if he made a land? sorry but I'm trying to understand as much as possible to find my mavic.

 

[Fly Dawg]

I can't understand where we see that the failsafe action is set in land? I'm sure the failsafe is set to RTH. Also why would he find it further north-west if he made a land?

See the graph below to answer these questions. As was stated this appears to be a wind issue. Especially so at such a high altitude. Generally the Failsafe action will change only when that instance occurs, however in this case it was set to "Landing" for the entire flight, which to me says that setting was manually changed prior to takeoff. RTH is default. The reason for finding the aircraft much farther away, again would be due to the wind. Assuming the aircraft auto landed, it would take a very long time for it to land and still being pushed by the wind in the process.

 

[dm166]

you are very kind, your every answer is of great help to me! the wind on the ground that day was almost zero certainly at that altitude it would have been different.I don't know what happened but I would never have set land instead of RTH maybe my mistake was not wanted! however, I went there several times to find the drone but without success! if he had made a landing it had to be there and I should have found it! also immediately after the accident when I realized that it was not rth I went there a few tens of meters on the road but I did not take any signal! I do not know what to think. what do you recommend me to do? in any way I will go back there to look. can I ask you which software you use to analyze the data? Thanks again to everyone

 

[Meta4]

hello Meta4 thanks for the reply, very kind! I can't understand where we see that the failsafe action is set in land? I'm sure the failsafe is set to RTH.

Open the Phantomhelp link that shows your flight data in post #11
And click on the link to Download Verbose CSV
That gives a very big spreadsheet showing everything recorded in the flight data.
In Column GB of the spreadsheet, (its heading is MC_PARAM.failSafeAction) you can see what action was set for loss of signal.
In this case it was Landing.

Also why would he find it further north-west if he made a land? sorry but I'm trying to understand as much as possible to find my mavic.

The data showed that the drone was able to hold position at its altitude.
So in an autolanding, it should have been able to land without blowing further away.
But the drone was flying at 10 metres/sec on a heading of 317°.
If the drone lost signal, it would have continued in that direction for a few seconds before autolanding.
If the drone lost power and crashed, its momentum would also have carried it further in that direction as it fell.

 

[dm166]

thanks again, today there is a storm here and I can't go to check, I hope it will stop as soon as possible. so if the failafe was set to earth I should find it there where it has lost the signal I have to look carefully. the drone was doing a POI at 10m / s i should only know after how many seconds it started with the landing to calculate how many meters ahead it went from the last known point. specified how many seconds it takes from the loss of signal at the start of landing? how do you do it in case you are doing a POI? I ask you these questions to calculate the landing point as precisely as possible. I have already been there but the protection is so thick that it seems impossible to find it, it is also inside an incision. thank you very much, you have been very helpful, I hope to find it and thus solve the problem.

 

[dm166]

today I went back there but without success. I have been searching for hours but with bad results. the vegetation is too dense and the only way to find it is to define an exact position in order to narrow the area. can anyone help me to predict the behavior of the mavic? how long did you keep flying with the POI function before landing? As a result of how far would he have strayed from the last known point? thanks to you I discovered many more details! I am very confident in you and I believe that thanks to you I will be able to find it.

 

[sar104]

This doesn't look like a wind problem. The wind field at flight altitude was a consistent 15 mph (7 m/s) out of the north - well within the capabilities of the Mavic 2. Additionally, there were no precursor indications of signal degradation prior to the disconnect, which would have occurred if there were an impending link issue. If the app had lost connection with the RC then the aircraft would have continued to fly until it the battery depleted to the smart battery go home level, and then returned to the home point, but your post suggests that the aircraft actually lost contact with the RC. If that was what happened then it was most likely an aircraft shutdown due to power failure - a battery disconnect.

It's worth noting that the disconnect occurred immediately after the RC input went from sticks centered to up throttle:



The disconnect followed so quickly that no climb was recorded. Battery disconnects often follow sudden stick inputs.

If that was the case then the aircraft position and velocity, together with the computed wind field, can be used to estimate a descent trajectory. That yields the following result:



Plotted on Google Earth, that looks like this:



The yellow pin is the predicted crash location.

 

[dm166]

Hi sar104 thanks for your answer. So you think it was a battery outage? Have you read the other posts? Others in the forum wrote that my failsafe setting was on landing. So he should have landed at the loss of the signal and not go back! The problem is that I went to the place but I cannot find the drone, I have beaten a large area but the vegetation is too dense and therefore I have not found anything! He was doing a POI so how long did it take before I stopped the POI and started landing? So we could calculate the landing point. However, the last input you see of the throttle was me immediately when I saw the interruption of the signal to try to raise the drone and resume the signal! thanks again you have been very kind.

 

[sar104]

Hi sar104 thanks for your answer. So you think it was a battery outage? Have you read the other posts? Others in the forum wrote that my failsafe setting was on landing. So he should have landed at the loss of the signal and not go back! The problem is that I went to the place but I cannot find the drone, I have beaten a large area but the vegetation is too dense and therefore I have not found anything! He was doing a POI so how long did it take before I stopped the POI and started landing? So we could calculate the landing point. However, the last input you see of the throttle was me immediately when I saw the interruption of the signal to try to raise the drone and resume the signal! thanks again you have been very kind.

The failsafe setting is irrelevant if the drone lost power - it only activates on signal loss, and there is no reason for signal loss at that point. The up throttle recorded at the end cannot have been after the disconnect, because it would not have been recorded.