How to retrieve flight log and video after FPV Total Loss?

[Awoolford]

Greetings. I am new to this forum after suffering a total loss at sea of my DJI FPV.

Looking for some advice and guidance on how to obtain the flight data and download the last 10 seconds from the DJI App or Goggles to try and figure out what happened.

It looked like a prop failure occurred while the drone was offshore and it simply tumbled into the sea where it is unrecoverable (RIP). Trying to determine if it was a bird strike or something else.

 

[BudWalker]

Greetings. I am new to this forum after suffering a total loss at sea of my DJI FPV.

Looking for some advice and guidance on how to obtain the flight data and download the last 10 seconds from the DJI App or Goggles to try and figure out what happened.

It looked like a prop failure occurred while the drone was offshore and it simply tumbled into the sea where it is unrecoverable (RIP). Trying to determine if it was a bird strike or something else.

Take a look at this explanation
.DAT available

It's focused primarily on retrieving the .DAT log but also explains how to retrieve the .txt log. The .DAT is preferable but won't exist if the Fly App is set to synchronize with DJI. The .txt isn't quite as informative as the .DAT.

If you attach the log(s) to a post I can take a look.

 

[Awoolford]

That's very helpful, thank you. I will retrieve what I can and post it here

 

[Awoolford]

I’ve attached a decoded CSV of the data, a screenshot from Airdata (the service I used to decode the data) showing the weather conditions, the corresponding raw .txt and .DAT files and the find UAV videos showing the loss.

In the video, you will see the drone in stable flight and then a sudden propellor failure on the right, from which neither the onboard avionics nor I could recover. We suffered a total hull loss as a result, where the drone fell uncontrollably from the air into the sea. The propellor seemed to have broken in such a way that it also disabled the motor, and the blades got jammed into the engine. Therefore both the propellor and the forward right engine failed almost simultaneously.

Any insight you could provide as to the cause of the accident would be much appreciated.

Files:
Video of loss, flight and weather data
(Updated to Google Drive)

AirData:
AirData information

 

[BudWalker]

I’ve attached a decoded CSV of the data, a screenshot from Airdata (the service I used to decode the data) showing the weather conditions, the corresponding raw .txt and .DAT files and the find UAV videos showing the loss.

In the video, you will see the drone in stable flight and then a sudden propellor failure on the right, from which neither the onboard avionics nor I could recover. We suffered a total hull loss as a result, where the drone fell uncontrollably from the air into the sea. The propellor seemed to have broken in such a way that it also disabled the motor, and the blades got jammed into the engine. Therefore both the propellor and the forward right engine failed almost simultaneously.

Any insight you could provide as to the cause of the accident would be much appreciated.

Files:
Video of loss, flight and weather data

AirData:
AirData information

I can only see the .txt via AirData. I'm not set up to do iCloud. Could you attach the .DAT to your next post. The file name of the .DAT will be
FLYxxx-033-YYYYMMDDHHMMSS.DAT

I'm pretty sure the left back motor was blocked causing the FPV to tumble rolling CCW and pitching up.

 

[Awoolford]

I've attached the .DAT file as requested, but the folder I linked on iCloud should hopefully open on any platform, including Windows. The folder includes the video as well as other data. I suspect the front right motor as the video shows the prop stationary in the later few frames. Trying to determine if it was a prop failure or something else.

 

[Awoolford]

Sorry, just noted the folder wasn't public. Just copying over to google drive. Will update the link shortly.

 

[Awoolford]

Google Drive link to the same files (including loss video)

 

[BudWalker]

The .DAT confirms the loss of propulsion was the right front. Here we can see the time integrated X and Y gyros.

The FPV is tumbling; pitching up end over end (blue plot) and rolling CW (green plot).

The right front motor data (red plots) shows increased commanded speed and current while the speed is decreased.


However, both the speed and current data are flat-lined which I suspect means some kind of sensor malfunction.

There are several entries in the log that look like
[L-FDI][CTRL]: fault on , impact_in_air
but, I suspect there really wasn't an impact. If it were a bird strike I would expect there would be just one indication of an impact. I'm supposing that the high accelerations may have fooled the FC into thinking there was an impact.


But, OTOH this is the first time I've seen a propulsion loss for the FPV so it's hard to know for sure that the impact messages were due to the high accelerations.

 

[Awoolford]

Dear Bud,

Many thanks for the time you have spent on this and your detailed analysis. The graphs are very interesting. I apologise for the slow reply as this week has been quite busy, but having now reviewed your data, it does look a lot like a prop failure. There was no sign of birds in the video, although there were several seagulls in the area riding the gusts close to shore so I cannot completely exclude that possibility.

The video shows the tip of a stationary prop in several frames, stalled in a vertical plane of rotation. This would seem to imply a structural failure of either the prop or the motor mount and your analysis seems consistent with this.

Many thanks again for helping me out here. We have also been in touch with the prop manufacturers and they are doing their own analysis which will be useful.

 

[BudWalker]

Dear Bud,

Many thanks for the time you have spent on this and your detailed analysis. The graphs are very interesting. I apologise for the slow reply as this week has been quite busy, but having now reviewed your data, it does look a lot like a prop failure. There was no sign of birds in the video, although there were several seagulls in the area riding the gusts close to shore so I cannot completely exclude that possibility.

The video shows the tip of a stationary prop in several frames, stalled in a vertical plane of rotation. This would seem to imply a structural failure of either the prop or the motor mount and your analysis seems consistent with this.

Many thanks again for helping me out here. We have also been in touch with the prop manufacturers and they are doing their own analysis which will be useful.

Actually, I think it was not a prop failure. Rather, a motor obstruction, or motor failure, or failure in the ESC driving the motor. Losing a prop would cause a decrease in current and increase in speed. The opposite happened here.

 

[Awoolford]

I understand what you mean. When I say prop failure, I was thinking along the lines of a broken blade blocking the motor somehow. But yes, anything is possible.

 

[SWTSU]

If you don’t have DJI care, I just saw this one on EBay for $100 right now with a day left to bid. It would be a hell of a deal, if DJI will not replace it. Let me know if you want to bid on it, so I don’t. Haha

**GREAT** DJI FPV DRONE - FD1W4K -- ONLY | eBay

A great drone to have and use! What's Included?. If it's pictured it's included. These will cost more.

www.ebay.com

 

[Awoolford]

If you don’t have DJI care, I just saw this one on EBay for $100 right now with a day left to bid. It would be a hell of a deal, if DJI will not replace it. Let me know if you want to bid on it, so I don’t. Haha

**GREAT** DJI FPV DRONE - FD1W4K -- ONLY | eBay

A great drone to have and use! What's Included?. If it's pictured it's included. These will cost more.

www.ebay.com

Thanks for the heads up. I have already bought a replacement so feel free to bid away at your heart's content!