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

[Meta4]

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.

From a great deal more flying experience than you have, I know that such a prompt is rarely seen.
If you have truly lost signal, there would be no point to it as the drone would never know you pressed anything.

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.

I certainly wouldn't go pushing the RTH button after RTh had initiated.
But that's because I know that pressing the RTH button while RTH is active will cancel RTH and leave the drone hovering waiting for you.
If I was uncertain what was happening, I'd switch off the controller.

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

But if signal was reconnecting as you were pressing the RTH button, you may have cancelled it.

I'd like to invite you all to read the title of this post and read my blog to fully appreciate my moaning.

I read it looking for details of the incident.
It was much too long and with too much moaning.
Few facts, with a lot of guessing for things that can't be known.

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.

You don't know what happened but you've guessed and assumed anyway.
Without supporting data, there's no way your assumptions can be proved.
At least some are certainly wrong.

From experience and what can be seen in the data, some possible causes of a lost drone can be eliminated.
Whatever happened to your drone, happened after the signal was lost so there is no data to explain the mystery.

Losing a drone isn't pleasant but every time we fly, we are choosing to take a risk.
There are things you can do to reduce the risk.
You could only fly within 100 metres
You can learn a lot more about the drone and how it is programmed.

You chose to fly well out of sight which means you wouldn't be able to see the drone and might not know where it went or what happened to it if things went badly.
One of the risks involved was the possibility of losing the drone

 

[Deleted member 94047]

Here are the relevant bits (according to me) from what your log shows:

1. Obstacle Avoidance was disabled - is there a chance the AC collided with something mid-flight? It would explain the sudden loss of connection and the subsequent failure of the AC to return home)

2. AC was configured to RTH in the event of a loss of connection between RC and AC

3. The RTH button on the remote was never pressed - if you did indeed press the RTH button, you did so incorrectly and therefore it didn't register in the logs - how exactly did you press the RTH butoon?

4. The AC never entered a GOHOME fly state during the entire duration of the flight

5. Battery was performing nominally till the end of the flight log, so there is no reason to suspect a sudden loss of power

6. Nav Health was nominal and I don't see any errors in navigation.


I am more inclined to believe the AC impacted or collided with something. But you know the environment you flew in better than anyone, do you think this is likely?

I am sure nothing like this ever happened to anyone.

As for this; well don't be so certain. A lot of mishaps happen, some go unexplained, but a lot is explained and we all learn from the explanations. You seem to have convinced yourself that you are at no fault even before you examined the facts - that attitude will not help you to learn from your mistakes and we all make mistakes

 

[m80116]

Since the complaint unless we consider the very detailed description of the event a moan, my background and so on is about three paragraphs long, I shall assume that 3 out of about 25 is too much moaning for you, after a heavy loss and possible impending personal injury liability. Can I just guess you're just intolerant to justified moaning ?

I don't assume things. I report facts. The drone drifted away, out of my control, I've had TOTAL loss of communication both up/down link.

 

[Meta4]

A small correction

3. The RTH button on the remote was never pressed - if you did indeed press the RTH button, you did so incorrectly and therefore it didn't register in the logs - how exactly did you press the RTH button?
4. The AC never entered a GOHOME fly state during the entire duration of the flight

3. If RTH button was pressed after signal was lost (which is most likely), it would not show in the flight data.
4. The drone may well have commenced RTH but we have no data to show this.

 

[Meta4]

Can I just guess you're just intolerant to justified moaning ?

I'm sure you can, you've guessed much already in this thread.
I'm not interested in moaning, particularly when it's based on assumptions and guesses.
I read your tale of woe, just wanting to find details to start work on the data.

I don't assume things. I report facts. The drone drifted away, out of my control I've had TOTAL loss of communication both up/down link.

Just for one example, you don't know that the drone drifted away at all.
You know you flew it out and the data stopped.
There is no evidence of what happened after that.
Your suggestion that it drifted away is just a guess and very likely, an incorrect one.
You've gone on to guess further that there are all kinds of faults with the Mavic despite having no proof and probably not enough experience to be sure of anyway..

 

[m80116]

1. Obstacle Avoidance was disabled - is there a chance the AC collided with something mid-flight? It would explain the sudden loss of connection and the subsequent failure of the AC to return home)

The only way to disable obstacle avoidance is to tape up the bottom sensors in the Mavic Mini. It wasn't disabled, I didn't tape anything.

2. AC was configured to RTH in the event of a loss of connection between RC and AC

That's what normally happens and it's not user configurable in the Mavic Mini

3. The RTH button on the remote was never pressed - if you did indeed press the RTH button, you did so incorrectly and therefore it didn't register in the logs - how exactly did you press the RTH butoon?

Of course during recorded flight there was no need to depress it. Once the connection was abruptly terminated and after some minutes after which I expected the aircraft to be in sight or already landed I started to depress it in the hope that somehow disregarded the complete loss of up/down link and it blasted the RTH signal for my drone (S/N tied) in every possible frequency channel at maximum power (far beyond the CE and FCC rules).

4. The AC never entered a GOHOME fly state during the entire duration of the flight

Agreed, it should have entered auto-RTH after several seconds from the link loss.

5. Battery was performing nominally till the end of the flight log, so there is no reason to suspect a sudden loss of power

Instead I believe it is an option, not necessarily for the battery which was correctly installed and clicked in, but for a defect in the power board manufacturing, be it a solder defect a faulty component or something else. The same could be said for the aerials.

6. Nav Health was nominal and I don't see any errors in navigation.

And the weather was good, perfectly clear, almost no wind and no geomagnetic inteference.

I am more inclined to believe the AC impacted or collided with something. But you know the environment you flew in better than anyone, do you think this is likely?

No. If you're interested I can PM you the video which shows the flight. Anyway I expected a jolt in the pictures before a total link loss if it impacted something (like a pigeon or a seagull for example).

 

[Deleted member 94047]

A small correction

3. If RTH button was pressed after signal was lost (which is most likely), it would not show in the flight data.
4. The drone may well have commenced RTH but we have no data to show this.

True, and I stand corrected. I was just going by what is in the log and the log does show the RTH button on the remote was not activated and the AC never entered a GOHOME fly state. Anything could have happened after the disconnect and there would be no way to know. But the key here I think lies in figuring out why the disconnect happened in the first place. Perhaps if the OP uploads the DAT file from their mobile device, we could have a little more data to go with.

 

[m80116]

Just for one example, you don't know that the drone drifted away at all.
There is no evidence of what happened after that.
Your suggestion that it drifted away is just a guess and very likely, an incorrect one.

Attributing guesswork to me for your own convenience doesn't make your cause any more valiant.

I haven't done a single speculation in my entire blog about the cause or faults. I didn't expect such a vein of spite for one of your age.

 

[m80116]

Perhaps if the OP uploads the DAT file from their mobile device, we could have a little more data to go with.

Here it is 19-12-26-04-33-04_FLY026.DAT

Also... I have message #45 under moderation approval, I am sorry not to be able to promptly respond to one analysis of the flight data.

 

[Meta4]

Attributing guesswork to me for your own convenience doesn't make your cause any more valiant.

I haven't done a single speculation in my entire blog about the cause or faults. I didn't expect such a vein of spite for one of your age.

Perhaps you don't understand the meanings of guess, proof, assume etc.
I'm a scientist and I won't speculate on things for which there is no evidence or proof in the flight data.
Unless you have evidence to show that your drone difted away, you can't reasonably say that it did.
To say it is an unsupported guess.

The drone could have had a complete power loss or collision with a bird, or it could have hovered when you cancelled RTH anad landed when the battery ran down etc.

Likewise with your assertions of serious faults with the drone.
Unless you can show what they are and show proof, there's no point advancing that theory.

 

[Dakarenduro]

Having quickly read this through this thread, from an outsider's perspective (ie. my perspective) the first thing I saw was the distance you traveled within an urban environment. 300+ meters on a wifi control link. And I assume a CE variant of the controller?

To me, heck yes you would experience signal loss and whatever followed simply because you chose to fly a mini over 300meters away. Then you claim a hardware failure vs. a pilot error in judgement.

I am sorry for your loss. Losing a drone sucks. Every time I fly I try to mitigate the risks as much as possible with my intended flight. I would not fly a Mavic Mini at that distance in that environment.

 

[Sticksandgrips]

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.

Again line of site. At 300 meters you can not physically see your drone.

 

[Deleted member 94047]

Here it is 19-12-26-04-33-04_FLY026.DAT

I can't see anything out of the ordinary there. But then again, my analysis skill is in its infancy so it is likely I missed a big clue staring me in the face. It is about time to call on @sar104 , @BudWalker , @Fly Dawg and put an end to this mystery.

 

[chriscuk]

So flying into the winds on a CE model on in a built up area at 300m distance. I'm sure issues would appear at some point.
Looking at the map it looks like you was flying it straight down a road so effectively you could SEE it but you've got to think of all of those houses you past. How many of those had WiFi. How many of those wifi signals would have been FAR FAR FAR closer to the drone than you.

Sucks you've lost it but it looks like this was human error rather than an error with the drone.
It also looks like the last place it was flying was over a large road junction. Maybe it got hit by a truck or something.

 

[dkuhne]

Sorry for your loss. Flying a mini in such a built up area, without line of sight, is surely asking for trouble though. Think how many other Wifi connections will have been in that area.

I smashed my First Mavic Air into wall, because I was flying in a built up area. Live and learn.

Despite it clearly being my fault, I sent DJI a sobstory letter along with the drone........and they replaced it for free! They may offer you some
me money off your next purchase if you sent them the flight logs.

 

[Deleted member 94047]

Wind direction was towards you.

I would have thought that would be an advantage. The last few seconds of the flight show the AC starting to travel back reaching a speed of 7.0mph before the log ends; the wind would have brought it closer to pilot and RC rather than blowing it further or away. It also makes RTH easier for the AC as it woudn't have been fighting the wind. But AC never entered RTH as far as we can see from the logs; and if did enter RTH after the log ends, it would have come towards the home point and either a connection would have been re-established or the pilot would have been able to spot it before it presumably got blown past the home point by the wind.

 

[dkuhne]

Pilot error
You flew into 22 mph (9.8m/s) winds.
Wind direction was towards you.
Check along the flight path slightly to the north.
Please use UAV forecast to tell you of upper level winds.
It shows 2.7 mph (1.7m/s) winds on the ground which can be deceiving.
See the following log of yours with a subscription account.
Weather, in flight winds and wind map

Flying into the wind wouldnt cause signal loss though would it?

 

[chriscuk]

Imagine that you're at one side of a really big field and a friend is on the other. If you shout they can hear you and you can hear them.
Now get a handful of people standing in various places in the field all shouting at the top of their lungs different things.
Repeat what you tried first and see if you can still hear or understand your friend.

Chances are the other people closer to either of you will drown out the sound from you or your friend.

It doesn't matter if you can see them if something else is far closer making far more "noise" than you they wont hear you.

 

[slup]

Imagine that you're at one side of a really big field and a friend is on the other. If you shout they can hear you and you can hear them.
Now get a handful of people standing in various places in the field all shouting at the top of their lungs different things.
Repeat what you tried first and see if you can still hear or understand your friend.

Chances are the other people closer to either of you will drown out the sound from you or your friend.

It doesn't matter if you can see them if something else is far closer making far more "noise" than you they wont hear you.

No signs of WiFi interference are shown in the logs in this case ... but in theory you are correct.

Pilot error
You flew into 22 mph (9.8m/s) winds...

Think the wind factor in this case are of minor importance ... the wind was overall in the flight mainly below the spec of 8m/s, it's only in 3 short occasions that the wind exceeds that & then during a very short time.

This is the highest calculated wind ... only continued for 5 seconds, but can explain the slight "bulge" in the flight path as seen.



I'm instead still puzzled by the flight log & the abrupt end... and that what's in the log doesn't show anything that isn't normal ... this together with the belief from the OP that he lost the connection (but that doesn't show anywhere in the log).

I early thought about the cable between the device & RC ...

If the cable between the RC & device came loose the RC would still be in control but the video stream should have stopped in the device as shown in below pic. In this case the RC LED is still green & no auto RTH will be initiated. (Yeah I know this is GO4 but do the Fly app show the similar behavior?)



If the device/RC connection doesn't get reestablished the log will show no connection loss as per below pic.


If the connection device/RC recover & the video stream continues the log will show that disconnect ...



If we take a look at a real disconnect between the AC & RC it will look like this ... in GO4 at least. The LED on the RC is red.



The 2 pics showing a disconnect AC/RC compered with one showing a disconnect between device/RC is somewhat similar for an untrained/unexperienced eye & may very well trick the operator to believe that he lost connection to the AC & can't operate it anymore & start to wait on the auto RTH.

And by being tricked by this & together with pushing RTH button multiple times (starting RTH & then cancelling RTH)... it either just hovered until auto land or drifted slightly as it wasn't commanded & hit something in that tight space were the log ended.

This is highly speculative ... but can't find reasons that make it unlikely.

 

[GerdS]

In theory also the same could have happend as happend to me few days ago. My MM was on its way home to me and when I hovered for a moment it suddenly begun loosing altitude without any control input. If I would just have looked onto my phone screen I might not have seen that in time. But as I am usually flying with goggles I was immediately aware of the problem and increased altitude by maximum throttle for returning safely. This happened only once while best weather conditions, calm wind and about 5°C, so no explanation yet.
Meanwhile I have also updated to 0400 firmware and not seen this problem occuring again.