Mini 2 Flyaway? DJI analysis seems inconclusive

[Jeffcho]

Flight Log Here

Experienced a flyaway / signal disconnect and wasn't able to retrieve it. I sent the analysis file to DJI but I'm not understanding their conclusion.

I made sure my signal and GPS sats were good before I sent it out for a straight back quickshot. That went well so I sent it back out manually with a slight pan to the left. Barely 400ft out, the signal suddenly dropped out and my video feed went grey.

There wasn't any wind and the visibility was sufficient. Can anyone here give more insight towards what happened?

Here's what DJI sent back as analysis:

1. The aircraft worked Tripod mode.
2. Flight Time T=05:06 , Relative Height H=4.2 m, Distance to Home Point D=117.2 m, the pulled back the pitch stick and moved the yaw stick to the left, the aircraft would crashed when it was flying backward and turned the yaw to the left.
3. Incident coordinate: 36.2070125, 29.645478

According to the analysis, the incident was caused by pilot's misoperation.

That doesn't fully make sense to me as I have done that maneuver many times in the past with no issues. How does moving the yaw to the left completely flip the drone over?

 

[slup]

The failsafe action was set on RTH at a height of 52m above take off location. At the signal loss the battery was at 27% & the Mini 2 was slightly higher than the HP at a distance of 117,5m & was flying with a speed of 5,7m/s backwards.

No obstacles was in between the last location for the Mini 2 & the HP (red arrow) ... & the distance to some possible obstacles behind the craft was still far according to the sat. picture (red dashed arrow).

The wind speeds was as you say very low, so that wasn't any issue in this flight. No rapid uncommanded craft movements are indicated in the log around the time for the signal loss so no impact can be detected before the log ends.

So ... in the end nothing at all indicates that your Mini 2 couldn't RTH safely.

All this indicates that the signal loss you saw instead was a total power loss, making the Mini 2 free fall.

DJI's analysis is nothing more than what I have seen... they have some speculation about a crash that can't be indicated in the log though. The true fact is that what happens after the last line in the log is unknown ... & nothing indicates that the craft maybe should fail the RTH.

 

[Meta4]

Flight Log Here

Experienced a flyaway / signal disconnect and wasn't able to retrieve it.

Your flight data has nothing to suggest that the drone flew away and the reason signal was lost, is almost certainly that the drone had a total power loss.

According to the analysis, the incident was caused by pilot's misoperation.

That doesn't fully make sense to me as I have done that maneuver many times in the past with no issues. How does moving the yaw to the left completely flip the drone over?

Usually DJI's data analysis is fairly good, but their explanation can be poor.
But in this case, whoever did the analysis has no idea what they are doing and their conclusion is very wrong.

You were fly flying backwards in Tripod Mode at 4.5 metres/sec and you pushed the left stick to the left to rotate the drone anti-clockwise.
After doing that for for 25.5 seconds the flight data stopped.

Even in Normal Mode, this would not crash the drone.
But in Tripod Mode, the rotation of the drone was very slow - it had only rotated 200° in 25 seconds.

I would get back to DJI and request a new analysis of the data.

Why wasn't it possible to retrieve the drone?
It was lost only 117 metres from the launch point and most likely fell straight down.
The wreckage should be quite close to 36.20701 29.64548.

 

[Jeffcho]

The failsafe action was set on RTH at a height of 52m above take off location. At the signal loss the battery was at 27% & the Mini 2 was slightly higher than the HP at a distance of 117,5m & was flying with a speed of 5,7m/s backwards.

No obstacles was in between the last location for the Mini 2 & the HP (red arrow) ... & the distance to some possible obstacles behind the craft was still far according to the sat. picture (red dashed arrow).

The wind speeds was as you say very low, so that wasn't any issue in this flight. No rapid uncommanded craft movements are indicated in the log around the time for the signal loss so no impact can be detected before the log ends.

So ... in the end nothing at all indicates that your Mini 2 couldn't RTH safely.

All this indicates that the signal loss you saw instead was a total power loss, making the Mini 2 free fall.

DJI's analysis is nothing more than what I have seen... they have some speculation about a crash that can't be indicated in the log though. The true fact is that what happens after the last line in the log is unknown ... & nothing indicates that the craft maybe should fail the RTH.

View attachment 155558

Thanks for the write up. I waited about 5 minutes thinking it would RTH but to no avail. I initially thought it might of struck something from behind but the tragectory was clear and your flight path render reaffirms that?

Has there been any other instances of seemingly random power losses on here?

 

[Jeffcho]

Your flight data has nothing to suggest that the drone flew away and the reason signal was lost, is almost certainly that the drone had a total power loss.

Usually DJI's data analysis is fairly good, but their explanation can be poor.
But in this case, whoever did the analysis has no idea what they are doing and their conclusion is very wrong.

You were fly flying backwards in Tripod Mode at 4.5 metres/sec and you pushed the left stick to the left to rotate the drone anti-clockwise.
After doing that for for 25.5 seconds the flight data stopped.

Even in Normal Mode, this would not crash the drone.
But in Tripod Mode, the rotation of the drone was very slow - it had only rotated 200° in 25 seconds.

I would get back to DJI and request a new analysis of the data.

Why wasn't it possible to retrieve the drone?
It was lost only 117 metres from the launch point and most likely fell straight down.
The wreckage should be quite close to 36.20701 29.64548.

Appreciate the response. I'll probe DJI support more and report back on what they say.

I tried searching for it for an hour but it dropped in an area of dense trees and bushes. The Mini 2 shaped and coloured rocks didn't help either. It was getting dangerous scrambling off the hiking trail so I stopped.

 

[slup]

...Has there been any other instances of seemingly random power losses on here?

Yep, several ... but mostly from Mavic 2's.

The distinctive signs of a total power loss is usually an abrupt video/signal loss out of harms way from possible obstacles & that the log shows absolutely nothing out of the normal... no large attitude changes (would indicate a crash into something if it was the case), no intermittent & growing number of shorter signal losses, a correct chosen failsafe action (RTH, not hover or land) enough battery levels for a RTH, no heavy head winds that risk draining the battery on the way to the HP & nothing in the way back to the HP with the chosen RTH height.

...I'll probe DJI support more and report back on what they say.

Besides their speculative idea about a crash as a cause for the abrupt video/signal loss, it's not much more to say, DJI usually avoid speculation when the cause isn't in the log. In most cases DJI want to see that the blame is theirs in the log in order to take responsibility... in incidents like this when the craft can't be retrieved (& the onboard log can't be investigated by them), the cause is unknown & they will most likely at most offer you some percentage off if you purchase a new drone.

 

[Capt KO]

Try DJI again but not as a flyaway, rather signal lost and not retrievable. You have gained some good additional information here. Good luck, I’ve had pretty good success with DJI customer service.

 

[Jeffcho]

Contacted DJI again with the data collected here and they reevaluated it, said the data is inconclusive and that they'll send me a new Mini 2 free of charge under warranty. Thanks for the input everyone.

 

[lalojamesliz]

Contacted DJI again with the data collected here and they reevaluated it, said the data is inconclusive and that they'll send me a new Mini 2 free of charge under warranty. Thanks for the input everyone.

This is exactly why I love forums with helpful people like this place!