Mavic Mini lost connection, did not RTH and is now (I think) in the sea...

[tomwilkinson91]

Hi all,

Any advice/knowledge greatly appreciated. Here's the log from today's flight (DJI Flight Log Viewer - PhantomHelp.com). Everything was going fine until the connection was lost. There was a notification saying that if connection wasn't found within 11seconds then it would RTH. However, this never happened. Can anyone provide any insight? Thanks in advance! Tom

 

[Starz]

Does seem a bit odd.
Hang loose, the expert will arrive.

 

[2Mavics4AManiac]

No real idea, but if I had to guess it looks like maybe a lost or broken connection with battery or snapped/lost a prop ? goes greater than 45 degrees pitched at the end with hard turn at speed and loses all air speed at that point. Abrupt end to telemetry seems to indicate power failure


edit to add

water depth seems to be only about 65 feet near where transmission ends, and topographically the bottom is very level. Depending on harbor traffic, and water clarity you may be able to fish it out with some help from a diver


easy dive within recreational limits

 

[Meta4]

No real idea, but if I had to guess it looks like maybe a lost or broken connection with battery or snapped/lost a prop ? goes greater than 45 degrees pitched at the end with hard turn at speed and loses all air speed at that point.

I'm not sure what flight data you're looking at but it's not the OP's flight.
There's no speed, no hard turn and no pitching.
His drone was hovering for 16 seconds until the data just stops.

 

[BadWolf1]

Everything looks pretty normal.

• You had been 1000m + from the home point, and the end of the log you are less than half that
• 15 seconds before the end you let go of the elevator the drone comes to a hover, using a little pitch and roll to hold against the wind, and you turn it while hovering. Nothing untoward there. You seem to continue the hover for a few seconds with data coming back suggesting everything is normal .
• The battery ticks down from 44% to 43% during that time, so low battery is not an issue. Failsafe is set to return to home throughout.
• Height is stable throughout. No sudden changes in pitch or roll. Nothing which says "Drone falling out of the sky", quite the reverse - the data at the end is saying "drone making slight adjustments to hold position" And then it stops.

A sudden stop somewhere which doesn't seem to be on the edge of signal range suggests some kind of power off - the battery came out or similar. If you have the dat file there may be more in that , but the only thing odd in the log is that it ends.

 

[tomwilkinson91]

Hi all, wow thanks for looking into this, appreciate it a lot. I've attached the other versions of the flight logs if that provides any more insight? What do you think the likelihood of DGI replacing the Mavic Mini would be? It's not something I can retrieve, so hoping warranty might cover it? I don't think I've done anything wrong here but if the logs can't even explain it then not sure what DGIs stance will be? As you say, winds weren't strong and it wasn't at its limits so I'm still baffled... Thanks in advance!

 

[BadWolf1]

I've had a quick look at the DAT, and it seems to be the same story ... complete normality with a sudden stop. Maybe one of the real experts will find something

A motor failure , prop failure, arm breaking, bird-strike/other impact, uncommanded descent, battery failure, would all show loss of stability and/or loss of height in the final moments of a log this one ends with 15 seconds or so of the drone hovering and sending back "holding position" with data about what it is doing to achieve that. It wasn't moving to go out of signal range, so it seems to have stopped sending. (Or the controller stopped receiving and the RTH system had a failure of its own - which is an improbable coincidence.)

You can only ask DJI. There may be an answer I can't find , otherwise it's "what is the policy on unexplained mid air shut-downs"

 

[tomwilkinson91]

Thank you so much for taking the time to look at the file and reply, again I appreciate it. It's a mystery. It'll be interesting to see DJI's stance on it. Cheers, Tom

 

[TerryToast]

Hi Tom, we spoke in person about 15 mins after you lost your drone. I’m glad you made it into the forums.

For everyone else, I can confirm the weather was perfect. No wind, no rain, etc. I was flying a Mavic Air 2 about 500 metres away from Tom, with no issues.

 

[itsneedtokno]

Any news from DJI?

 

[tomwilkinson91]

Hi Tom, we spoke in person about 15 mins after you lost your drone. I’m glad you made it into the forums.

For everyone else, I can confirm the weather was perfect. No wind, no rain, etc. I was flying a Mavic Air 2 about 500 metres away from Tom, with no issues.

Hello!! Thanks for finding me here! At least someone managed to make the most of those amazing conditions...!

They've opened a case and am still awaiting a response. Will let you know what they say.

 

[tomwilkinson91]

Any news from DJI?

Yes! They have confirmed that it is a warranty case based on their data analysis, and will be sending a new drone soon. Happy days - thanks for your input everyone!

 

[TerryToast]

Yes! They have confirmed that it is a warranty case based on their data analysis, and will be sending a new drone soon. Happy days - thanks for your input everyone!

Tom, when your new drone shows up, give me a shout if you’d like a quick drone lesson in Manly. Say in Keirle Park, rather than 500 metres out in Sydney Harbour, while you learn the ropes.

 

[tomwilkinson91]

Hi all, me again!

So a similar thing ALMOST happened today - flying around the same spot (yes, I know, silly me), and it lost connection out of the blue again. Luckily this time it did RTH and the drone is fine. It has though, made me wonder if there’s something wrong with my RC? I’ve got the flight logs here, which I’ve also sent to DJI to see if they can shed any light… Makes me so nervous to fly it! Anyone got any ideas whether this is a common issue or maybe something wrong with my new drone/RC?

 

[TerryToast]

Don’t sweat it. I lose connection all the time in Manly, even with the more advanced Mavic Air 2 (which has Occusync 2.0). It’s a congested area with lots of wifi and other interference, so your range will be limited to 500 metres or so with the Mavic Mini.

If you set your RTH to 80 metres, you should be fine. So long as you don’t fly in high wind, as the Mini is light and may blow away, rather than RTH.

 

[Rattydude77]

I would try a new spot with the drone and make sure the home point is set could be something in the area. My wife and I fly in the Adirondacks and one spot I got a magnetic Interference on the smart controller but nothing was around no metal no cell service so I landed the bird safely never flew that spot again and never got that message again point of the story is theres could always be something that Interference any little sign of that bring the bird down but sometimes we dont get the warning.Glad you got a new drone.

 

[Meta4]

point of the story is theres could always be something that Interference any little sign of that bring the bird down

Despite all the posts suggesting similar things, interference won't fly your drone away or make it crash to the ground.
At worst (and rarely), it could swamp your control signal which would initiate RTH.
That's it.

 

[tomwilkinson91]

Thanks everyone. It's interesting that the first time I lost connection (and the drone never RTH) and this most recent time, the drone was almost exactly in the same location. The difference through, was where I was flying it from (much closer to the drone second time round). Perhaps it is just a busy spot in terms of interferences.

What I'm understanding is that this type of interference/loss of connection is (relatively) common. I'm just glad that it returned to home as it should and hope it will do the same in the future. Can't describe that feeling of relief to hear it suddenly hovering overhead!!

Won't be flying in that spot again, and glad to have eventually got the shot that I was after:

 

[Meta4]

It's interesting that the first time I lost connection (and the drone never RTH) and this most recent time, the drone was almost exactly in the same location.
The difference through, was where I was flying it from (much closer to the drone second time round). Perhaps it is just a busy spot in terms of interferences.

Wat I'm understanding is that this type of interference/loss of connection is (relatively) common.

There is some confusion here.
In your first incident, losing connection did not cause the loss of the drone.
Losing connection was a symptom of the drone losing power.
When the power goes off, the drone falls and the connection is gone.

Interference is common and normal in urban areas.
It rarely causes any real trouble and at worst, it might swamp your control signal, which initiates RTH.
But there's no indication that you lost signal this time because of interference.

I can't see any reason that the location would be a problem and I'd happily fly my drones there again and again (if there are no airspace restrictions).

 

[tomwilkinson91]

There is some confusion here.
In your first incident, losing connection did not cause the loss of the drone.
Losing connection was a symptom of the drone losing power.
When the power goes off, the drone falls and the connection is gone.

Interference is common and normal in urban areas.
It rarely causes any real trouble and at worst, it might swamp your control signal, which initiates RTH.
But there's no indication that you lost signal this time because of interference.

I can't see any reason that the location would be a problem and I'd happily fly my drones there again and again (if there are no airspace restrictions).

Thanks @Meta4, in your opinion what do you think caused the loss of connection this time? Is it something I should be concerned about hardware-wise (RC maybe?), or something that I just need to accept might happen every now and again?