Analyze my mystery crash log

[lenn]

Being an anonymous lurker for some time, I was hoping to get some help from the community.

I experienced a mysterious and serious crash while flying today. The MP was only 350ft away, 150ft up but obscured by a tree when it crashed. Furthermore the video feed cut out (whole screen turned grey). The video recovered doesn't show an impact either. The height and location of the crash made a collision very unlikely. I know, another potential "fell out of the sky cases", but was hoping someone with more experience reading logs can help me understand what happened (signal loss? interference? collision?).

This is the crash log from the drone (it still powers up) and run through DatCon:
DJI_ASSISTANT_EXPORT_FILE_2018-09-14_16-19-41.FLY002.xlsx

This is the video I recovered from the on-board SD on the MP:

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I'm an amateur but experienced pilot - flying a 3DR solo very frequently for the last 3 years with two minor crashes in my first year under my belt, and none in the last 2 years despite much more flying. This one has me scratching my head, and was hoping the community could help

EDIT: Included other files I've uploaded along the way:

Log from my phone: DJI Flight Log Viewer - PhantomHelp.com
Original DAT log from the MP: DJI_ASSISTANT_EXPORT_FILE_2018-09-14_16-19-41.DAT

 

[lenn]

To add, the battery was fully charged (95% at the time of crash), I had strong satellite health and was flying in GPS mode. I found the carcass approximately 10 feet from the last flight position in the middle of the road (suggesting it didn't collide with the building). My limited experience with the log shows "regular" motor RPM, voltage and amperage.

"just dropped out of the sky".....

 

[ac0j]

Maybe the battery popped off in flight?, Maybe a propeller came off in flight? Hard to tell if you didnt see it fall. because likely that stuff could have came off when it hit.

 

[Simmo]

@sar104

 

[Meta4]

but was hoping someone with more experience reading logs can help me understand what happened (signal loss? interference? collision?).

I'll have a look if you supply the flight data in a more user-friendly form.
Go to DJI Flight Log Viewer - Phantom Help
Follow the instructions there to upload your flight record from your phone or tablet.
Come back and post a link to the report it gives you

 

[lenn]

I'll have a look if you supply the flight data in a more user-friendly form.
Go to DJI Flight Log Viewer - Phantom Help
Follow the instructions there to upload your flight record from your phone or tablet.
Come back and post a link to the report it gives you

Thanks for the guidance Meta4! Found the logs and uploaded them... although I think the decoded blackbox logs may be more detailed. Learning something new with these flight logs though!

DJI Flight Log Viewer - PhantomHelp.com

 

[lenn]

Maybe the battery popped off in flight?, Maybe a propeller came off in flight? Hard to tell if you didnt see it fall. because likely that stuff could have came off when it hit.

I would've expected the logs to show a huge change in motor speed along with a fair amount of pitch and yaw if it were the props. The battery would be an interesting culprit. It was ejected on impact. Would DJI consider an unseated battery a "hardware issue" under warranty? I've had this thing for 7 days....

 

[Meta4]

Thanks for the guidance Meta4! Found the logs and uploaded them... although I think the decoded blackbox logs may be more detailed.

It has a lot more information that you see at first glance and has the added advantage of showing the flight and surrounds and makes it easy to start working out what happened.
Unfortunately your flight data doesn't show the crash or anything that might have contributed to it.
It just stops with the drone in stable flight.
The pitch, yaw and roll indicators haven't changed in the seconds before the data stops.
You have lost signal and whatever happened after that hasn't been captured.
That could be because signal was blocked and flight continued or it could because of a sudden complete loss of power.
Some details that might help ... where was the drone recovered?
Do you know what it collided with?

 

[ac0j]

Sounds exactly like the Battery disconnected in flight. Either it wasnt fully locked in, or it overheated and swelled popping it off. The drone data will show more than the device data, and wont stop when the remote disconnected. If you can get that data.

 

[lenn]

It has a lot more information that you see at first glance and has the added advantage of showing the flight and surrounds and makes it easy to start working out what happened.
Unfortunately your flight data doesn't show the crash or anything that might have contributed to it.
It just stops with the drone in stable flight.
The pitch, yaw and roll indicators haven't changed in the seconds before the data stops.
You have lost signal and whatever happened after that hasn't been captured.
That could be because signal was blocked and flight continued or it could because of a sudden complete loss of power.
Some details that might help ... where was the drone recovered?
Do you know what it collided with?

Thanks Meta4. The drone was recovered approximately 10feet from the last GPS location in the middle of the street. No buildings or trees were tall enough in the immediate area to collide with at 150ft or at the 100ft RTH height.

I'm beginning to think this was a loss of power. While the log from my phone reported a "signal block", the log recovered directly from the MP black box using DJIAssistant (which is not dependent on the RF signal) also shows 150ft steady with sudden truncated data. Any other hypothesis? I don't have DJI care - so I'm trying to gauge if this looks like a standard warranty claim.

 

[lenn]

Sounds exactly like the Battery disconnected in flight. Either it wasnt fully locked in, or it overheated and swelled popping it off. The drone data will show more than the device data, and wont stop when the remote disconnected. If you can get that data.

Thanks for the input ac0j! I pulled the drone data, ran it through the DatCon decoder (Apparently the device data is somewhat encrypted) and posted it as the spreadsheet in my original post. It seems to indicate a sudden loss of power too. The drone and battery is only a week old (otherwise manufacture date in late 2017). I wouldn't expect battery swelling.

I was under the impression that MP batteries were "picky" about being fully seated. Where the MP would refuse to take off with a partially seated battery....

 

[Meta4]

Thanks Meta4. The drone was recovered approximately 10feet from the last GPS location in the middle of the street. No buildings or trees were tall enough in the immediate area to collide with at 150ft or at the 100ft RTH height.

I'm beginning to think this was a loss of power. While the log from my phone reported a "signal block", the log recovered directly from the MP black box using DJIAssistant (which is not dependent on the RF signal) also shows 150ft steady with sudden truncated data. Any other hypothesis? I don't have DJI care - so I'm trying to gauge if this looks like a standard warranty claim.

OK .. wasn't clear what it might have hit but that makes it look like the power just stopped.

It might have been battery related or perhaps something in the drone's circuitry.
The SIgnal Block message just means the controller has lost signal and that's what happens when the drone shuts off (or flies behind and obstacle).

I'd synch your flight records, go to DJI's online help and start a chat with their people to get things moving on a warranty claim.

 

[lenn]

OK .. wasn't clear what it might have hit but that makes it look like the power just stopped.

It might have been battery related or perhaps something in the drone's circuitry.
The SIgnal Block message just means the controller has lost signal and that's what happens when the drone shuts off (or flies behind and obstacle).

I'd synch your flight records, go to DJI's online help and start a chat with their people to get things moving on a warranty claim.

Thanks for the suggestion Meta4. I synched the records and opened up a warranty claim this afternoon. I boxed up the body and damaged battery (despite the site telling not to - the phone rep. suggested to do so). I couldn't recover the gimbal that ripped off, but it looks like they will be able to boot and read the blackbox - like I was able to.

I'll update us once I hear back. Thanks for the time and energy with the logs so far. Open to receive input from anyone else here

 

[Robert Mitchell]

Following.

 

[GavieboyDji]

Sounds exactly like the Battery disconnected in flight. Either it wasnt fully locked in, or it overheated and swelled popping it off. The drone data will show more than the device data, and wont stop when the remote disconnected. If you can get that data.

Exactly what happened to my Mavic pro 1 battery swelling and was that puffed up it disconnected itself and dropped like a stone right in front of me straight on to concrete 50 feet in front of me.

It's either that what happened here or a [emoji211] bird. In his crash video you see a bird fly straight over his drone in front of the building he was filming.
I've looked up at my drone and seen crows swooping down at my Mavic and spark all the time you never see them on the fpv it's only when you actually look up at your drone you catch them. I had it happen to my Spark yesterday luckily I seen it coming and quickly moved the spark backwards.

 

[GavieboyDji]

Thanks for the input ac0j! I pulled the drone data, ran it through the DatCon decoder (Apparently the device data is somewhat encrypted) and posted it as the spreadsheet in my original post. It seems to indicate a sudden loss of power too. The drone and battery is only a week old (otherwise manufacture date in late 2017). I wouldn't expect battery swelling.

I was under the impression that MP batteries were "picky" about being fully seated. Where the MP would refuse to take off with a partially seated battery....

Could of been a bad battery. But like you say it would show up in the data same with a prop that would show too.

Can someone with a drone blocker technology make a drone drop power. I've always wanted to know that?

Sorry for the highjack it's always worried me when I'm flying at events if someone could do that to a drone.

 

[lenn]

Could of been a bad battery. But like you say it would show up in the data same with a prop that would show too.

Can someone with a drone blocker technology make a drone drop power. I've always wanted to know that?

Sorry for the highjack it's always worried me when I'm flying at events if someone could do that to a drone.

No worries, thanks for the input. A bird strike would be interesting. However, I'd imagine we would see the on-board log show a ton of yaw/pitch etc. along with a quick drop in altitude. Battery issue seems more and more likely. Also - my battery is brand new, maybe only 5 charge cycles and manufactured a year ago at most.

I'm thinking a defect is more and more likely, I'd be quite annoyed to receive a bill at this point. I took a screenshot of the "disconnected" FPV which may have a screen 2 seconds after the video. I was flying well above the extensions/patio of the building. No way I would've hit it, or be able to recover the drone in the street if I did.

I assume shipping, processing and damage assessment will take 7-10 business days at this point. It is so hard to be patient.

 

[sar104]

Being an anonymous lurker for some time, I was hoping to get some help from the community.

I experienced a mysterious and serious crash while flying today. The MP was only 350ft away, 150ft up but obscured by a tree when it crashed. Furthermore the video feed cut out (whole screen turned grey). The video recovered doesn't show an impact either. The height and location of the crash made a collision very unlikely. I know, another potential "fell out of the sky cases", but was hoping someone with more experience reading logs can help me understand what happened (signal loss? interference? collision?).

This is the crash log from the drone (it still powers up) and run through DatCon:
DJI_ASSISTANT_EXPORT_FILE_2018-09-14_16-19-41.FLY002.xlsx

This is the video I recovered from the on-board SD on the MP:

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

I'm an amateur but experienced pilot - flying a 3DR solo very frequently for the last 3 years with two minor crashes in my first year under my belt, and none in the last 2 years despite much more flying. This one has me scratching my head, and was hoping the community could help

Those data don't show anything significant, but they have not been converted at the full data rate. You will need to post the original DAT log file rather than a filtered conversion.

 

[lenn]

Those data don't show anything significant, but they have not been converted at the full data rate. You will need to post the original DAT log file rather than a filtered conversion.

Thanks for the input sar104. Not sure what kind of privacy I'm giving up, but I've attached the original DAT log. Let me know your thoughts:
DJI_ASSISTANT_EXPORT_FILE_2018-09-14_16-19-41.DAT

 

[sar104]

Thanks for the input sar104. Not sure what kind of privacy I'm giving up, but I've attached the original DAT log. Let me know your thoughts:
DJI_ASSISTANT_EXPORT_FILE_2018-09-14_16-19-41.DAT

OK - that shows no indication at all of any power supply problem. The motor voltage is flat right up until the log stops. In cases where a battery disconnect occurs then the voltage record sags over 70 ms or so until it falls below the threshold for FC operation.

That strongly suggests that the cause was FC processor failure or, in other words, the FC froze/crashed and that simply shut down the aircraft.