Why I do believe there's a HUGE problem with the Mavic Mini - Flew AWAY the 2nd day

[m80116]

I can't deny having linked to this discussion in a couple of threads, but I've done so because I've felt they were related to faulty calibration, and because I haven't found my drone hovering where I expected to be or return I can also link my case to that (among other problems).

Anyway...you can forward to me any specific issue in PM and I'll try to address it, removing the link where it is not allowed.

Just to clear up the facts even more... (already posted this onto some other threads).

My Mavic Mini suffered 3 failures combined.

1. It clearly unlinked from my remote both up/down link wise 330 mt from me, in line of sight. How do I know it wasn't just loss downlink: whatever the reason it should have flown back to home because the auto-RTH was initiated (RTH altitude correctly preset, home point correctly updated). 5 GHz clear (1 SSID broadcast), 2.4 GHz quite busy but not on every channel.

2. It failed to initiate or complete the auto-RTH after link loss. Very mild wind, mild temp, battery 76% at link loss, remote control above 60%. RTH pressed after some minutes from the auto-RTH and the drone was not showing up. A button press in an unlinked remote can't do anything... I was just nervous.

3. Failed to auto-land and hover stationary near the last point it was still connected. I was there way before the battery could have been depleted, the drone was never found. It means 100% it drifted away.

You can read all the details of my unfortunate experience in my blog post as mentioned in the first entry

 

[slup]

My take on this ...

1.Depending on that I can't find any other loss of signal then very minor from the log.
2.Together with OP's claim (or thought) that the connection were lost due to that the live stream disappeared?
3.And hitting the RTH button multiple times.

Can the phone have been disconnected from the RC due to bad connected cable ... tricking the OP that the connection were lost & by then pushing RTH multiple times starting/cancelling the RTH so the AC just stayed hovering until auto land? That would also explain that the log from the phone just stopped at 33m altitude & 322m distance

 

[slup]

1. It clearly unlinked from my remote both up/down link ...

Can't see anything regarding that in the log ... 100% signal score all the way to the last line in the log.

 

[m80116]

The phone was still linked with the remote, I remember accessing settings to verify.

I shall point out that I am not claiming a lost connection because of loss of video downlink. The manual clearly indicates that auto-RTH would take place for loss of downlink. That hasn't happened unfortunately.

Depressing the RTH button after some minutes (I'd say about 2) after the initial auto-RTH should have been initiated (from just 300 mt away, 30mt of height with a RTH height of 50) seemed to be the next (il)logical thing to do... because despite my wishful thinking the drone was out of remote control and nowhere in sight.

Anyway... thanks @slup for taking a bit of your time to dig deeper into my flight data. What's not usual in my case is the abrupt loss of connection combined with the auto-RTH fail and positioning hold which obviously the flight log data can't demonstrate.

 

[Meta4]

What's not usual in my case is the abrupt loss of connection combined with the auto-RTH fail and positioning hold which obviously the flight log data can't demonstrate.

Without flight data to confirm, we cannot be sure that RTH and/or position holding failed.
We just don't know what happened.

Trying to go further than we have data is just guessing.
One possibility already mentioned is that RTH did commence but you cancelled it.
Again we don't have data to show that this happened but it is a real possibility.

 

[slup]

The phone was still linked with the remote, I remember accessing settings to verify.
...

Don't see any problem to access the settings in the app even though the cable got lose to the RC ... & again, nothing in the logs can prove that the connection RC/AC were lost, all that's left is just speculations unfortunately.

 

[m80116]

The transmission folder channels list is unpopulated when the remote is disconnected.

Well... to be fair I struggle to see a log that ends mid-air without landing or signal loss. I am led to believe some hardware fault or firmware crash intervened.

 

[Fly Dawg]

Well... to be fair I struggle to see a log that ends mid-air without landing or signal loss. I am led to believe some hardware fault or firmware crash intervened.

One thing you are missing here. The Video and Telemetry Downlinks are Seperate from the RC Control.
The log ended because you lost Video Feed, which also transmits the Telemetry Data. You can still have
control of the aircraft, without your knowledge, if you are flying BVLOS. Which obviously was the case here.
As mentioned before, you can not even see the mini at 300 meters. From the data we have, I think it can
be said that ( From this Data ) it was a signal loss issue and nothing more. You did recieve signal warnings.

 

[DanMan32]

How can the RC beep indicating RTH if signal was lost first? It can't know AC is in RTH if it can't hear from the AC. That's why I asked about the LEDs on the RC, to determine if signal was really lost.

I have experienced one way signal loss with my P3, but not with my M2. Not enough experience with Mini at signal loss to understand it's nuances.
In the case of the P3, since it was still hearing from me without me knowing (lost video and telemetry), it just hovered for 4 minutes until battery got low where it RTH'd due to low battery. I know I had only uplink since I read the DAT files on the RC and AC. RC said signal loss, AC said "what now boss?".
I don't think the Mavics, at least my M2, is prone to one way signal loss long term. Unfortunately we can't read the AC DAT files on M2/Air/Mini to get AC perspective on these kind of issues.

 

[new2mavic]

The manual clearly indicates that auto-RTH would take place for loss of downlink. That hasn't happened unfortunately.

This is copied from the manual :

If only the downlink video is lost but the downlink telemetry data can still be received, the DJI GO will just ask if you want to initiate RTH. It will not go home by itself. As you have not mentioned seeing such prompt, I have reason to believe that the telemetry data was lost as well. It is uncertain if the uplink control signals could still reach the drone though.

From the log, the drone was behaving normally all the way to the end of the log. Beyond that, it's all guessing. I can imagine several possibilities :

1) If the uplink was still working and you did not apply any input , the drone would just hover there. As you have pressed the RTH button several times and it did not show up at the home point. It has probably stopped on the way back due to RTH being cancelled and finally autoland. If this has indeed happened, you should be able to find it along it's way home.

2) If the uplink was lost as well, it should have returned home by itself no matter how many times you have pressed the RTH button. As it didn't, this possibility can be ruled out.

3) The drone suddenly entered an abnormal state. Anything could have happened.

4) It flew into a wormhole and went to other time / space ?

 

[Fly Dawg]

The manual clearly indicates that auto-RTH would take place for loss of downlink. That hasn't happened unfortunately.

No it will not. Please read the above post#30....

 

[Sticksandgrips]

I mean the video you posted showed many times you had connection issues. At that point and time you honestly should have rethought about flying and bringing the drone back towards you. Multiple times it said check antennas. Log files or not. This seems more and more like user error. You obviously had interference happening and proceeded with the flight.

 

[Sticksandgrips]

And these guys are trying to help you figure it out and you go back to the same thing every time. At what point do you realize these guys know what they are doing and have knowledge. Does it suck yes. But nothing is perfect in this world.

 

[m80116]

One thing you are missing here. [...]

I am not missing anything I am sorry, you're not pay attention to what I've written.

When the downlink is lost there is a prompt to initiate RTH, a prompt I never received and the RC was beeping because of total link loss. And no... I did not receive any signal warning, on the contrary the signal was full strength and good quality until signal loss, because I was flying it close to me (which 300 m certainly is).

 

[m80116]

No it will not. Please read the above post#30....

I believe the prompt goes on and it initiates auto-RTH automatically when no key is pressed to cancel it. I've already tested this feature.

 

[m80116]

This is copied from the manual :
View attachment 89482
If only the downlink video is lost but the downlink telemetry data can still be received, the DJI GO will just ask if you want to initiate RTH. It will not go home by itself. As you have not mentioned seeing such prompt, I have reason to believe that the telemetry data was lost as well. It is uncertain if the uplink control signals could still reach the drone though.

From the log, the drone was behaving normally all the way to the end of the log. Beyond that, it's all guessing. I can imagine several possibilities :

1) If the uplink was still working and you did not apply any input , the drone would just hover there. As you have pressed the RTH button several times and it did not show up at the home point. It has probably stopped on the way back due to RTH being cancelled and finally autoland. If this has indeed happened, you should be able to find it along it's way home.

I notice many of you still arguing with the fact that I depressed the RTH button more than once. What would you do when you expected the drone to regain signal in 10 seconds should the worst happen and you already waited 2 or 3 minutes at home point, so plenty of time for the drone to show up above your head and land.

The remote was TOTALLY disconnected, no prompt was ever shown, and an auto-RTH was initiated after a certain amount of seconds.

 

[m80116]

I mean the video you posted showed many times you had connection issues. At that point and time you honestly should have rethought about flying and bringing the drone back towards you. Multiple times it said check antennas. Log files or not. This seems more and more like user error. You obviously had interference happening and proceeded with the flight.

Yes... I had BIG BIG problems... I just received two warnings of -Adjusting antenna- mid path, lasted about 1 second and I did not even had time to read because they disappeared. The path as shown in the data analysis plot is completely GREEN with full signal strength. I am sure nothing like this ever happened to anyone.

Are you familiar with flying a Mavic Mini or not ? Should one come back for something like this you can completely give up droning.

 

[m80116]

By the way I'll write once again... I am not crying over myself.

I am not really seeking for an explanation since there can't be one... I appreciate cues and prompts but I don't need easily dispensed judgement, not because I can't stand it but because trying to explain a technical fault ignoring even the basic facts is just a plain loss of time.

I mean the usual exaggeration : -you were flying into a BLIZZARD-, there was no wind, the plot clearly shows the drone didn't have to fight any and historical weather data is freely available.

Or something like: -you're doing it wrong mate. you were out of signal- I think if one reads and sees the data can figure that out for himself, despite the entire episode being very well described in my blog.

I'ld like to invite you all to read the title of this post and read my blog to fully appreciate my moaning. I am afraid until we all raise awareness about the dangers and quite high level of unreliability of these flying machines we're gonna stay where we stand... at the pole, at a complete loss and dismay after our beloved drones crashed or flew away by themselves. I've read too many cases and frankly I don't believe they should even allow to market a product that can have this fallacy of control.

 

[GerdS]

From the map it looks to me as if you have been out of line of sight, what will explain the connection loss on that distance. One solution would have been increasing altitude on the first connection warning.
And there is a high chance that the Mini has crashed into a building or landed on a roof.

 

[m80116]

From the map it looks to me as if you have been out of line of sight

GerdS, I am sorry to use your case to prove my point but... what map are you looking into? My flight path is a complete straight line, line of sight with my observation point.
Also I DID INCREASE the altitude from 26 to 33 meters just past mid time into the flight. So...you didn't see my data plot or read my blog.

At 26 meters the real aircraft to ground hight is even more because the initial slope in the road leading to the city center, anyway I also have a video (anyone interested can ask me access to) that clearly shows 26m is already above every building passed by.