Fell from sky

[sar104]

The only thing I can add to this is that the sample rate of the .txt is just too low to really tell the difference between CW and CCW. Here is an incident where a propulsion issue occurred and the P3S was rotating CCW.
View attachment 92251

This plot was generated from 30 Hz data. The same data sampled at 10 Hz (the .txt file sample rate) produces this plot
View attachment 92252

I can't really tell if this is CW or CCW.

Agreed, but in this case the direction of initial rotation is clearly captured at the 10 Hz sample rate. It then transitions into full 360° rolls, with more minor excursions on the pitch and yaw. It's not quite like the usual spin following motor loss. It's almost as if it lost two motors.

 

[Clockman]

I just rebuilt a P4 with more damage because the camera yaw arm was also broken off. The owner said the same thing, that it dropped from the sky from about a 100 feet. When I disassembled it, I discovered a ribbon cable that connects the flight controller to the left ESC board was pulled out of it's socket. This would have shut off the 2 left motors instantly. I couldn't be sure whether this occurred during the crash though and I didn't look at the flight data. It's been flying well after several flights now.

 

[Jerry H]

The flight data shows none of the usual indicators of something you might have done wrong .
The battery in particular was fully charged at launch time and still healthy at the end.
At 1:31.2 the trouble started. You just eased off on the sticks after going fast and up in Sport mode and it was all downhill from there.
The error messages suggest a genuine hardware malfunction and the case looks like one to take up with DJI.
Upload the flight record to DJI - click on the cloud icon on the flight record page in the app.
Then go to their online help at: DJI Support - Phantom 4
Click Online Support at the bottom of the page and start a chat to get things started.

Is it possible to get this much info from the phantom 3 standard? If so I haven' figured out how.

 

[BudWalker]

..... It's almost as if it lost two motors.
.......

and

I just rebuilt a P4 with more damage because the camera yaw arm was also broken off. The owner said the same thing, that it dropped from the sky from about a 100 feet. When I disassembled it, I discovered a ribbon cable that connects the flight controller to the left ESC board was pulled out of it's socket. This would have shut off the 2 left motors instantly. I couldn't be sure whether this occurred during the crash though and I didn't look at the flight data. It's been flying well after several flights now.

and the invoice indicates the right ESC was replaced

View attachment 92228

Maybe the ESC wasn't plugged in properly?

 

[sar104]

Is it possible to get this much info from the phantom 3 standard? If so I haven' figured out how.

Mostly, yes, with a few differences in the exact logged parameters. The methods are described in the links below.

DJI Flight Log Viewer

Airdata UAV - Flight Data Analysis for Drones

How to retrieve a .DAT

 

[BudWalker]

Is it possible to get this much info from the phantom 3 standard? If so I haven' figured out how.

This site has references to just about everything that can be used to extract and view data from the P3S

DJI Phantom Accessories & Tips - Phantom Help

 

[sar104]

and

and the invoice indicates the right ESC was replaced


Maybe the ESC wasn't plugged in properly?

That sounds very plausible, but I cannot think of any definitive way to confirm it from the txt log data.

 

[sar104]

However, there was at least 0.6 seconds of right roll, past 90°, before any indication of a pitch change, which is hard to account for without simultaneous loss of lift from both right motors. And the CW yaw would be explained by continued left side propulsion.

 

[BudWalker]

However, there was at least 0.6 seconds of right roll, past 90°, before any indication of a pitch change, which is hard to account for without simultaneous loss of lift from both right motors. And the CW yaw would be explained by continued left side propulsion.

View attachment 92270

And there you have it. We don't need no stinking .DAT

 

[Clockman]

Separate the shell and have a look at the ribbon cable. If it's disconnected, most likely that's what happened.

 

[sar104]

And there you have it. We don't need no stinking .DAT

I guess the data are somewhat compelling, at least in the sense that having stared at them again for some time I cannot come up with an alternative hypothesis. But I want that DAT file. I need to see it....

 

[Clockman]

View attachment 92218

This is repairable. See my Youtube channel "Dalton Drone Zone." You can see the video of the rebuild. Same condition as yours.

 

[jeffgiff]

Sorry guys, Im not having much luck retrieving the Dat file. as the drone cannot be powered up and I was using a S7edge as my display at the time, I can't use I tunes to transfer files. Or at least I can't figure out how to.

 

[sar104]

Sorry guys, Im not having much luck retrieving the Dat file. as the drone cannot be powered up and I was using a S7edge as my display at the time, I can't use I tunes to transfer files. Or at least I can't figure out how to.

If you can't power up the P4 then it won't be possible to retrieve the DAT file. However, as you probably saw from the discussion above, it's most likely the right ESC that disconnected or failed.

 

[jeffgiff]

ok thank you very much for your help. I guess Ill ask my repair shop for a discount on a new drone if the replaced esc failed or wasn't connected properly. not sure if I should be opening it up or let them do it?

 

[Dredd]

All props attached. Is there a way of uploading the dat files for you folks to look at? This drone has an interesting history and a rather lengthy story regarding dji warranty/support. Including the swap of a good battery for one that has the dreaded one bar blink. I sent the bird back to dji after two months of purchasing new, when it began to have esc errors. After djis keen support staff assessed it they determined that these errors were the result of a non flght impact. They said this was obvious due to the cracked upper and lower case and landing gear. This of course baffled me as I had sent the a perfect drone. Not a scratch on it with only 9hrs of flight. So i thought it must have been damaged in shipping and would deal with it when i got it back. So I had dji send it back without repairing it. Paid the postage. On return, would you believe it was exactly as I had sent it! Perfect, not a scratch on it with the exception of one of my brandnew batteries being swapped out for an old one that didn't work! I have all of this correspondence in emails. I have never been so pissed at a company.

I then took the drone to my local dji dealer who replaced an esc. This flight was the second since that repair.

 

[Dredd]

Oops sorry. What I meant to say was I had something under similar circumstances happen to me.

Your local DJI support are limited. Follow meta4’s advice. Send the data outlined to DJI themselves or to your local flagship store. It seems you may have a genuine case for them to review.

Use “flyaway” as your headline (my guy in HK advised this) which I did. DJI reviewed my data and replaced my drone (P4P), props & chip at no cost to myself. They would only tell me they deduced a system malfunction.

Good luck mate
Steve

 

[jeffgiff]

Thanks Dred, as noted previously I have had very poor service from DJI. To start, I would be happy if they just replaced the battery they stole from me.

 

[Clockman]

ok thank you very much for your help. I guess Ill ask my repair shop for a discount on a new drone if the replaced esc failed or wasn't connected properly. not sure if I should be opening it up or let them do it?

Let me know if you would like to sell it. [email protected]

 

[jeffgiff]

Let me know if you would like to sell it. [email protected]

Ill let you know.
Thanks
Jeff