Crash Analysis ATTI Drift - Response Time

[Alex Mavic 88]

Hello guys,

Few weeks ago, I unfortunately crashed my Mavic Pro in th middle of the beautiful Taroko Gorges in Taiwan.

The mission was launched a bit fast and was therefore a bit risky but space and visibility where OK, wind also OK.
I used the ActiveTrack mode. Around 1.20min on the video, the Mavic went out of ActiveTrack and passed to ATTI, then started drifting.

I started to act on the remote to go forward but the drone did not respond. 8 seconds later I crashed the valley.

I am trying to understand what happen in details and I would like your opinion.

You can have access to the flight record with my comments attached.

I might be missing something, I would like to understand whether it's a complete human error, a "fly away".
What is the usual "response time" in ATTI mode ?

All the information has already been provided to DJI Support.

You can see the video here:

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I did the exercice myself to synchronize the time on the video and the time of the log thats why I think It might not be totally a human error.

Thank you guys.

 

[Mavicpilot1988]

Looks like human error to me

 

[Robbyg]

I have not looked at the log but preventing a crash while flying at a distance when you unexpectedly go into Atti mode with only about 5 seconds before impacting something is not easy. I don't see any apparent attempt at control, maybe you did not push the stick hard enough to overcome the momentum or you pushed the roll in the wrong way forgetting it was facing you. It does not matter! Yes it's pilot error but given the situation the result would have been the same for most of us.

Rob

 

[Alex Mavic 88]

I know it tooks time to look at the logs so to make it quicker I am putting the video of the fligh and controller action online now. The mission was clearly to risky. But I really wonder what could be the response time of Mavic.
Ok video 2 is ready you can find it here:

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Rob at first I was exactly thinking that, I was thinking the mavic was facing me and that I pushed it even more in the drifting direction. But when i look the orientation it seems no in fact.

 

[ed1nh0]

Regardless whether it was pilot error or not, I would not use the Active Track so far from the target. Notice you're a gray spot on a gray background. It's very easy to lose you of sight!
Regrettably the worst happened. You took the risk but like others well said, it could happen to any of us.

 

[TrayBoz]

That was some cool, I mean awful, crash footage. It looks like the mavic almost regained control just before it hit the ground. I was afraid you were accidentally going to run into a car while you were riding and looking at the mavic. Now THAT would have been some awesome, I mean gruesome, footage.

How hard was it to retrieve the mavic and how much damage was done to it?

 

[Robbyg]

I can see Alex really wants to know what he was up against.
I looked at the video again and you can see the craft move forward at the 1:27 mark, but it was already in the web of branches and just moved further into them.

Here in GREEN you can see the Elevator inputs coming in just as all hell breaks lose on the drones X, Y and Z axis movements (hitting and crashing).



So Alex you can see from the time you hit the stick you had zero time to correct the situation. Maybe if you had been faster on getting to the sticks, but that's the rub of ATTI mode, when it happens your brain takes a few seconds to process the data and react.

Rob

 

[Alex Mavic 88]

First guys I would like to say that of course if I try to understand that's because I feel ashamed about what happen. It will remains a very costly error.

Thank you Rob taking the time to analyze. The graphs is a good idea I tried to do it as well. Because I am not fully convinced about the last part. Actually before I was thinking the response time of the RC was too long. But when I look closer, I think the gain/sensitivity might have played.

Indeed you can see when I request elevator up, the Y axis immediately ramp up as well.

What do you think ?

Reading the "up and down" after impact I do not think it's related to Elevator requests. If it is in this case the response time is very very low, but I don't think so.

Since the ATTI starts, it took me 4 sec to react, too long yes. 3 sec after my reaction impact occurs, so yes it was kinda short.

Analyzing crash is interesting tough.

 

[Alex Mavic 88]

Regardless whether it was pilot error or not, I would not use the Active Track so far from the target. Notice you're a gray spot on a gray background. It's very easy to lose you of sight!
Regrettably the worst happened. You took the risk but like others well said, it could happen to any of us.

Ed you are right I did not think about that actually. This is a good point

 

[Alex Mavic 88]

That was some cool, I mean awful, crash footage. It looks like the mavic almost regained control just before it hit the ground. I was afraid you were accidentally going to run into a car while you were riding and looking at the mavic. Now THAT would have been some awesome, I mean gruesome, footage.

How hard was it to retrieve the mavic and how much damage was done to it?

Tray, I could not retrieve the Mavic. That was the worst feeling, *** frustrating. I could see the Mavic in the gorge blinking white, 42m down.
My friend wanted to go down the gorge actually thinking the height was like 15m. After a while I resigned I did not want any of us die just to get the bird down there.
Costly mistake (I bought the DJI Care - but you have to send back the drone to get a new one ! so I'm screwed )

 

[ed1nh0]

Alex, I feel sorry for you. I really am.
I put myself in your shoes and wonder how could I bring my drone back... maybe using an Inspire from someone else with a hook and flight for a risky rescue mission?
I don't know that place so I wonder infinite possible and inpossible ways to do that... Hope you find a way to get it back.
Regards

 

[TrayBoz]

VERY sorry for your loss. But you're right, not worth someone getting hurt for a wrecked $750 drone.

 

[HFMan]

I agree that the Mavic still should have reacted quicker than it did - there was 3-4 seconds there where you were pushing forward, and it seemed as if it was not really inclined to respond appropriately.

 

[Alex Mavic 88]

Hello guys, thanks for your compassion lol. Dji answered me I found their answer really unfair.
"From the flight record we can see that there is no movement on the controller".
Well. They must be kidding but anyway I have no choice but too accept their "expertise".
...