Can someone read my flight records and tell me why my drone crashed?

[proplatmavic]

first dat file off controller. Dropbox - 2017-11-09_09-50-15_FLY029.DAT

 

[proplatmavic]

I dont have the drone, I sent it back to DJI and bought a new one so I can't get the dat file off the drone unless it was stored on the card.

 

[Hollow Dog]

You got it.

Would you comment on how important it is to download these files off of a drone before it is sent back to DJI?
I assume it's pretty important and that you won't be able to get a copy of the files after they have possession of your equipment

 

[BudWalker]

first dat file off controller. Dropbox - 2017-11-09_09-50-15_FLY029.DAT

Is there another file with name 2017-11-09-XX-XX-XX_FLY030.DAT that's different from 2017-11-09_10-08-39_FLY030.DAT? 2017-11-09_09-50-15_FLY029.DATis from the previous flight.

 

[wxperson]

I know 90 feet is high, but i really wouldnt have expected all of the wings to snap like that from impact. To me, a graduate of my own university, id expect to see significant damage to a single side not everywhere. Which again to me makes me think there was some serious spin as that drone fell, not just a drop (which would result in a pretty well oriented fall as the main drag would come from the top of the drone, the props and wings).

So i would imagine such damage would happen if a motor failed and the drone was still powering the others.

I think it started falling from 280’

 

[sar104]

There's some strange stuff going on in this flight, with compass errors, motor current errors, speed errors and the motor obstructed error.

The yaw data look reasonable until around 280 seconds; the intial behavior is consistent with the rudder inputs, and then at around 190 seconds the FC takes over in GO HOME mode. At 258 seconds it switches to AUTO LANDING, and rotates the aircraft and descends. At 280 seconds, however, a series of unexplained yaw excursions begin, and continue until 332 seconds, when things really go bad.



In the initial descent phase, aside from the yaw excursions, the aircraft is not stable, with significant pitch and roll occurring:



Then, at 332 seconds, the aircraft pitches back and rolls right, and enters a 3 Hz spin, descending rapidly:



It doesn't look like the usual spin caused by a prop loss, instead spinning on a more consistent axis with the rear left oriented down. Its initial acceleration is close to free fall, decreasing as it speeds up:



It's difficult to determine exactly what is happening here without the detailed DAT file data, but the motor current errors around 100 seconds and the motor obstructed error at 334 seconds (coinciding with the start of the uncontrolled descent and counter-clockwise spin) suggest that one of the counter-clockwise motors may have seized (ESC failure?) - probably the rear left - imparting its angular momentum to the aircraft. None of which is obviously related to the compass and yaw problems.

 

[BudWalker]

There's some strange stuff going on in this flight, with compass errors, motor current errors, speed errors and the motor obstructed error.

The yaw data look reasonable until around 280 seconds; the intial behavior is consistent with the rudder inputs, and then at around 190 seconds the FC takes over in GO HOME mode. At 258 seconds it switches to AUTO LANDING, and rotates the aircraft and descends. At 280 seconds, however, a series of unexplained yaw excursions begin, and continue until 332 seconds, when things really go bad.

View attachment 24884

In the initial descent phase, aside from the yaw excursions, the aircraft is not stable, with significant pitch and roll occurring:

View attachment 24885

Then, at 332 seconds, the aircraft pitches back and rolls right, and enters a 3 Hz spin, descending rapidly:

View attachment 24886

It doesn't look like the usual spin caused by a prop loss, instead spinning on a more consistent axis with the rear left oriented down. Its initial acceleration is close to free fall, decreasing as it speeds up:

View attachment 24887

It's difficult to determine exactly what is happening here without the detailed DAT file data, but the motor current errors around 100 seconds and the motor obstructed error at 334 seconds (coinciding with the start of the uncontrolled descent and counter-clockwise spin) suggest that one of the counter-clockwise motors may have seized (ESC failure?) - probably the rear left - imparting its angular momentum to the aircraft. None of which is obviously related to the compass and yaw problems.

The characteristics of this incident look similar to this incident
Mavic crash after update

at least similar in that they both give me that hollow, wanting for a more compelling explanation feeling.

 

[msinger]

Would you comment on how important it is to download these files off of a drone before it is sent back to DJI?
I assume it's pretty important and that you won't be able to get a copy of the files after they have possession of your equipment

This thread is a perfect example of why it's important to retrieve the DAT flight logs before sending a Mavic in for repair. Unfortunately, many people don't know the DAT logs are stored on the Mavic.

 

[TotemLake]

Given the location, at 827 feet having a motor obstructed sounds like a bird strike to me. Eagle would be likely.

 

[wxperson]

I believe it was on the way down (free falling) before that message appeared.

 

[lisadoc]

This thread is a perfect example of why it's important to retrieve the DAT flight logs before sending a Mavic in for repair. Unfortunately, many people don't know the DAT logs are stored on the Mavic.

Out of curiosity, does anyone know if there is a method for retrieving the DAT files from a Mavic that won't power on? I'm sure DJI could do it but if you crash your drone and the battery is bad (and it's your only one) or the drone won't power on due to the crash, is there any recourse to retrieve the files? What if the USB port or the board is broken or loose and can't be connected to a computer, even if it powers up? I'm assuming that a fair number of crashes might result in such a condition.

 

[proplatmavic]

DJi said they would send me a fixed one for $221. They said it was my fault. I didn't even bother replying to the email, i just hit the paypal button and paid.

 

[sar104]

Out of curiosity, does anyone know if there is a method for retrieving the DAT files from a Mavic that won't power on? I'm sure DJI could do it but if you crash your drone and the battery is bad (and it's your only one) or the drone won't power on due to the crash, is there any recourse to retrieve the files? What if the USB port or the board is broken or loose and can't be connected to a computer, even if it powers up? I'm assuming that a fair number of crashes might result in such a condition.

They are on the internal SD card, so if you can extract that from the aircraft then I assume that it is readable. That's the only option I can think of if the Mavic will not power up.

 

[rs7trout]

DJi said they would send me a fixed one for $221. They said it was my fault. I didn't even bother replying to the email, i just hit the paypal button and paid.

I think it's pretty cool to know that DJI pretty much took care of it--even if it was your fault!! Good to know and thanks for shareing.

 

[Alky1229]

If it said “Motor Circuit Error” you shouldn’t have paid for it to be fixed or what not. That is a problem with the drone, mine said the same thing literally 2 weeks after I got it. Luckily it didn’t crash but it did stop flying. Sent it to DJI and they were gonna fix it, I fought we them about getting a new one seeing as how it was on 2 weeks old and bought from them. In the end they gave me a new one and it didn’t cost me anything because the “Motor Circuit Error” is not your fault

 

[Sailmakerx]

Yes all props were attached and broken except one

I would venture to guess either bird strike or the sticks were positioned towards the corners and you shut the motors off

 

[sar104]

I would venture to guess either bird strike or the sticks were positioned towards the corners and you shut the motors off

You should probably read the thread. It was definitely neither of those.

 

[scjerry]

DJi said they would send me a fixed one for $221. They said it was my fault. I didn't even bother replying to the email, i just hit the paypal button and paid.

Seems to be the going rate. For $204, they refused to send me a data analysis. I, too, hit the Paypal button knowing that it could be weeks before getting a replacement if I complained or delayed. The $221 may be a good price for repair. Too bad you had to pay it.

On the fact that DJI Assistant 2 can't access the FC's SD card w/o being powered up is a bummer, but I'm sure there is an engineering reason. Perhaps transferring the .dat files to the user SD card would satisfy the need. Assistant also won't allow access to its graphical analysis tool w/o a powered-up MP attached.

On the lack of awareness of users on trouble reporting procedures, maybe they've included instructions in their Go 4 on-line manual. DJI GO 4 Manual: The Pilot’s Handbook. However, I couldn't find a reference to the flight list, cloud upload or .dat file retrieval either there or in their Mavic Pro 1.8 manual. Maybe some else will have better luck.

I almost forgot, I purchased State Farm drone insurance for $50/year. Circumvents all of this.

 

[LarryM]

There's some strange stuff going on in this flight, with compass errors, motor current errors, speed errors and the motor obstructed error.

The yaw data look reasonable until around 280 seconds; the intial behavior is consistent with the rudder inputs, and then at around 190 seconds the FC takes over in GO HOME mode. At 258 seconds it switches to AUTO LANDING, and rotates the aircraft and descends. At 280 seconds, however, a series of unexplained yaw excursions begin, and continue until 332 seconds, when things really go bad.

View attachment 24884

In the initial descent phase, aside from the yaw excursions, the aircraft is not stable, with significant pitch and roll occurring:

View attachment 24885

Then, at 332 seconds, the aircraft pitches back and rolls right, and enters a 3 Hz spin, descending rapidly:

View attachment 24886

It doesn't look like the usual spin caused by a prop loss, instead spinning on a more consistent axis with the rear left oriented down. Its initial acceleration is close to free fall, decreasing as it speeds up:

View attachment 24887

It's difficult to determine exactly what is happening here without the detailed DAT file data, but the motor current errors around 100 seconds and the motor obstructed error at 334 seconds (coinciding with the start of the uncontrolled descent and counter-clockwise spin) suggest that one of the counter-clockwise motors may have seized (ESC failure?) - probably the rear left - imparting its angular momentum to the aircraft. None of which is obviously related to the compass and yaw problems.

 

[LarryM]

Sar104, what program are you using to create the graphs further up in this thread? (Doesn't quite look what I see with CsvView.) Thanks

Am I right that the Mavic DAT files are located in an internal memory in the MP, not in the removable SD card? I don't see DAT files when I look in the removed SD card (but I don't see the DAT files when I power up the MP without the SD card).