Lost my Mini 2

[GadgetGuy]

The most likely reason he lost communication with the drone is that it suffered a power loss and fell from the sky.
We don't know if that was what actually happened (would need to see data to confirm), but if it was, the incident could just as easily have happened 20 feet away.
There is no evidence to suggest that not being able to see the drone had anything to do with its loss.

Not having visual on the drone might add extra complications for the flyer, but it is rarely the cause of a lost drone incident.

It isn't entirely clear that he even lost communication with the drone. Might have still had communication, but just didn't realize it when the app crashed. Unless the battery was already in a critical power state, there should have been plenty of time to reboot the app, regain FPV view, and fly the drone back, regardless of BVLOS. Inexperience is the real cause. Refresh with Fly Away coverage is specifically designed for pilot errors like this. Only the log file can vindicate him, if DJI is truly at fault!

 

[GadgetGuy]

I didn’t get the opportunity to cancel RTH and fly manually as the screen went blank

This says it all! The app crashed. You likely still had full control with the RC, but just didn't know it.

 

[Chris Rees]

This says it all! The app crashed. You likely still had full control with the RC, but just didn't know it.

Looking back yes you absolutely right, if only I'd had the where with all to hit the RTH button on the rc. It won't happen again that's for sure! lesson learned

 

[Skwirl]

This says it all! The app crashed. You likely still had full control with the RC, but just didn't know it.

Which is exactly my point I was trying to make. If he could have seen the drone, he could have manually flew it back.
Thank you.

No apology necessary meta. Wouldnt want to dink your armor, lol.

 

[Chris Rees]

I have managed to find the flight record, if anyone can shed any light to confirm it was pilot error, I would very grateful. Thank you.

 

[Meta4]

Looking back yes you absolutely right, if only I'd had the where with all to hit the RTH button on the rc. It won't happen again that's for sure! lesson learned

If your drone has entered RTH and you posh the RTH button, you'll cancel RTH and leave the drone hovering until you give it some joystick input.
If you aren't sure whether the drone is/is not in RTH, the best option is to turn off the controller.

 

[Meta4]

I have managed to find the flight record, if anyone can shed any light to confirm it was pilot error, I would very grateful. Thank you.

The flight data shows a one-way flight over the sea.
The data ends with the drone in place 427 feet out, 186 ft up and climbing, climbing at 3 ft/sec.
There was plenty of battery, low wind and no glitches in the flight data.
The Failsafe Action was set to RTH.

The data just ends at 4:32.9 leaving us to guess what happened after that, but nothing to confirm what actually happened.
Sudden loss of power is one possibility.

 

[slup]

... it lost connection. Anticipating the fail safe return to home to kick in I didn’t panic. But, no, waited and waited and waited and nothing she just hovered there until (I assume) the battery depleted and she fell into the sea.

Well ... as in all these cases when the connection is lost (... weather it's RC-AC or RC-Phone) the log stops recording & all that happens after that is unknown.

Look like this was the last flight of several on the same power on ... you ascended & then flew sideways straight line out over the ocean ... there on 186ft height, with a distance of 432ft from your correctly recorded HP & with sufficient GPS reception the log ends.



It's mainly 3 things that ends a mobile device TXT log ...

-The motors stop... this a TXT records between motor start to stop

But it seems as you could see the AC hovering & then much later falling (landing) into the ocean ... so a sudden motor stop due to some unknown reason can be ruled out.

-The connection between the RC & AC is lost

If it had been a RC to AC disconnect your failsafe action would have kicked in ... it was set to "Go Home" & you was farther away from the HP than 20m (closer than 20m & it just lands on the spot), you had a properly recorded HP & a good GPS reception ... So think we can rule out that you had a disconnect between the RC & the AC.

-The connection between the RC & the phone (app) is lost ... either due to usb cable problems or a app crash

So a RC & phone disconnect then ... in this case you're still in control, even though your apps live view is gone, the AC will obey all RC commands as usual. So if you don't command anything the AC will just stay there & hover until the battery percentage reaches the lowbattery RTH threshold ... which in your case, being so close to the HP was at 14% battery... so with the average battery consumption that would have taken approx 16,5 minutes.

Here below is all the important telemetry data from the log, have placed the chart marker just in the end (right side at 273sec)... values for the different graphs from that moment is in the legend under the chart ...

(Click on the chart to make it larger)


So ... the only possible reason here is a disconnect between the RC & the phone as that wouldn't trigger the failsafe action. The AC would have been standing there and hover for quite a while as it there in the log end had 75% battery & the lowbattery RTH threshold was defined to 14% ... but then, why didn't the AC returned to home when the battery reached 14% ?

This is what's stated in the user manual about low battery RTH:


If you read the orange marked area ... I wonder if you constantly pushed the RTH button manually? If you did that you start & stop the manual RTH ... & when the lowbattery RTH activates, you cancel it by pushing the RTH button.

If you by mistake deactivated the lowbattery RTH the only thing that remains is the lowbattery autoland which was defined as 7% battery & would have started approx. 18,5 minutes after that you lost the live view.

Did you see the AC the whole time ... did you try to activate RTH manually, did you see it fall, or was it actually landing?

 

[Meta4]

But it seems as you could see the AC hovering & then much later falling (landing) into the ocean ... so a sudden motor stop due to some unknown reason can be ruled out.

I didn't get the impression that he saw it hovering from the incident description

 

[slup]

I didn't get the impression that he saw it hovering from the incident description

Well ... if writing as per below, it could indicate that he saw it hover, needs clarification from the OP, perhaps he only assumed that also.

...she just hovered there until (I assume) the battery depleted and she fell into the sea

 

[Deleted member 103366]

Then I didnt understand the directions on that site. The main issue for me is, I don't have the correct cable to connect my phone to my pc. So I clicked the link on PH which brought up program that has a subscription for it.

The PhantomHelp site of the link allows you to upload and process txt logs, one at a time, via the "Upload Your Flight Log" section on that page.
After it processes the log you can download the resulting csv and examine it at your leisure. Some folks then process that csv with other programmes that generate graphs etc. e.g CsvView.
The 'drawback' to the PhantomHelp page is that, because it's a freebie and possibly 'privately funded' and for fair usage, you are only allowed to upload 10 logs per 48 hours or something like that.
The bought 'version' you found the link to is for software that can be run on your computer.

Note, if you wish to examine logs from pre Fly app drones, CsvView and DatCon can be used without going to the PhantomHelp website. CsvView can also process the logs from the Mavic Mini but that may be restricted to 'earlier' versions of the Fly app and or firmware. I say "may be restricted" because I alway get it muddled up in my head whether or not it can process the logs from later versions and, if it can not, where the demarcation occurs.
If you wish to process txt logs from pre Fly app drones en-masse you can use TXTlogToCSVtool via a suitable command line one liner, see [TOOL][WIN] Offline TXT FlightRecord to CSV Converter
The MM version also processes my Mavic Mini txt's.

 

[Deleted member 103366]

If you are ever stuck, just switching off the controller will always initiate RTH (unless youve changed the Loss of Signal Action ... which almost no-one ever does)

A very good point.

 

[Michael Ainsworth]

I know this doesn’t help at all in these situations, but this is why I still prefer the original RC that I use with my MP.
If there is a phone or app disconnect you still have telemetry on the controller which allows you to bring the AC back.
I really don’t like the “upgraded “ controller I use with Air2S.

 

[EricJT]

In two and a half years, l have had only one video disconnect between my SC and M2P. When that happened, I had VLOS and was fully aware of the M2P's heading, so I was able to fly it back to me, albeit after pausing and thinking through the next step(s).

I never rely on the SC to navigate from and to my home point, given what I have invested in this hobby.

 

[HOG2K]

@Chris Rees i am not trying to be critical but the first thing i would have done given your situation would have been to press and hold the RTH button on the RC and if it had started bleeping then i would know that it was at least connected to the RC and trying to get home ,then i would have tried to reboot the screen device while this was happening and then once the drone was overhead and descending then just cancel RTH and land manually

Having not purchased my Air 2s yet nor any drone for that matter but I will all in due time. I do appreciate learning from all those who offer up their experiences toward problems that users post. I'm taking in all this information hoping that if I ever have a problem that I may be able to retain what someone did and get myself out of the sticky situation.

Thank you