Help with crashed P4 Standard - Drone flips and crashes during takeoff.

[Mikevipe]

Hello there,

Happy new years everyone!

Well, now for the good stuff. I was flying my P4 yesterday when the unthinkable happened. I had just flown a 17 minute flight which all was normal. After landing, I swapped the battery for the next flight. When I touched the take off and hover button on the screen the drone immediately took off at full speed, flipped and did a 360 at full speed, smashing right into the ground completely destroying it. Thankfully it crashed right between the cars and no outside damage was caused other than my ego haha.

I went into the DJI Go app and tried to upload the flight log but it showed 0 information for all data and after the Upload was completed it seems DJI or the app completely removed it. My only hope now is to retrieve it from the aircraft. The battery wont fit into the housing anymore so powering it up will require me to disassemble it to get to the battery connector. I saw in the datfile post that the dat files on certain drones are encrypted, can the one on the P4 Standard be read by us?

Video: Watch crash2 | Streamable
Different angle: Watch drone2-crash | Streamable

I am at a loss as to what happened. It is hard to see in the video but as soon as it took off it immediately started drifting back towards me about a foot and then shot into the sky. It was in P mode and attempts to do anything on the controller were unresponsive.

With this drone being 6 years old now its well out of warranty and I doubt DJI will do anything, is it worth the time and effort to attempt to retrieve the dat file? Has anyone seen anything like this before?

Any help is appreciated.

Thank you

 

[GFields]

Did you have a good GPS lock before you took off?

 

[Mikevipe]

Yes, I always wait for the GPS at the top to change from red to white and I had the Audible The home point has been set, please check it on the map.

 

[RodPad]

I watched the video.

If you really wants some facts.
You should really go this direction.

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

Rod ..

 

[Mikevipe]

I watched the video.

If you really wants some facts.
You should really go this direction.

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

Rod ..

Thank you Rod,

That was the first thing I tried but the log was 0s 0m and when I tried to upload to DJI in the Go app the log just disappeared. That is why I am hoping it can be retrieved from the aircraft:

I went into the DJI Go app and tried to upload the flight log but it showed 0 information for all data and after the Upload was completed it seems DJI or the app completely removed it. My only hope now is to retrieve it from the aircraft. The battery wont fit into the housing anymore so powering it up will require me to disassemble it to get to the battery connector. I saw in the datfile post that the dat files on certain drones are encrypted, can the one on the P4 Standard be read by us?

I don't know if there is a delay for the log on the remote streaming from the aircraft but it was empty.

 

[Mikevipe]

Do you have a PC with DJI assistant 2 installed , or only in app , couple more links ,might help find something, saw while looking for where to find if no data
Yip watched crash many times and it was a strange one ,
Maybe @msinger or @Meta4 can fly by for a look and guide you on what to do . Links below probably useless but never know

DatCon Introduction

DJI Fly and DJI GO 4 Flight Record & Flight Controller Data Export Guide

If your aircraft suffers from an accident and Flight Record, simplified flight controller data or aircraft flight logs need to be exported, please refer to this article for help. #Product Usage

support.dji.com

Thank you Ian.

I followed the guide, I took the drone apart to get the battery connected and exported the dat files. The file is 375MB and I opened it in the DJI Viewer but its empty there's no data and the flight does not exist at all on the Ipad controller somehow its corrupted.

Here is a screenshot of the viewer with the dat loaded: dji hosted at ImgBB

Video of a different angle:

Watch drone2-crash | Streamable

Watch "drone2-crash" on Streamable.

streamable.com

I will try to get my neighbors camera to see if it catches the entire thing.

 

[John leach]

Hello there,

Happy new years everyone!

Well, now for the good stuff. I was flying my P4 yesterday when the unthinkable happened. I had just flown a 17 minute flight which all was normal. After landing, I swapped the battery for the next flight. When I touched the take off and hover button on the screen the drone immediately took off at full speed, flipped and did a 360 at full speed, smashing right into the ground completely destroying it. Thankfully it crashed right between the cars and no outside damage was caused other than my ego haha.

I went into the DJI Go app and tried to upload the flight log but it showed 0 information for all data and after the Upload was completed it seems DJI or the app completely removed it. My only hope now is to retrieve it from the aircraft. The battery wont fit into the housing anymore so powering it up will require me to disassemble it to get to the battery connector. I saw in the datfile post that the dat files on certain drones are encrypted, can the one on the P4 Standard be read by us?

Video: Watch crash2 | Streamable
Different angle: Watch drone2-crash | Streamable

I am at a loss as to what happened. It is hard to see in the video but as soon as it took off it immediately started drifting back towards me about a foot and then shot into the sky. It was in P mode and attempts to do anything on the controller were unresponsive.

With this drone being 6 years old now its well out of warranty and I doubt DJI will do anything, is it worth the time and effort to attempt to retrieve the dat file? Has anyone seen anything like this before?

Any help is appreciated.

Thank you

 

[John leach]

You mentioned that the P4 as several years old and possibly the following my help as I had a similar experience with my P3. The below is my assessment, and it may be right or wrong.
After time, the plastic under stress begins to fail and hair line cracks may appear (as the aero industry) which you may or may not notice. These cracks appear in the arms supporting the motors at the motor ends of the arms. The cracks initially make no difference to the performance of the craft, but slowly in time they will progress and the arm will loose its stiffness. The arms are under a lot of torque during movements, as in take off and any other high or low maneuvers. In your case, if we assume it was the slight degeneration of the plastic in one of the arms, and the stiffness began to fail on one side of the arm, at take off, the pull of the motor will make the motor start to move the arm with the motor causing uneven thrust, and craft out of balance. That then causes one or more of the other motors to accelerate more, to counteract the failing arms behavior, there then follows, high rpm of the motors to try to correct the out of balance thrust line by all of the motors. The failing arm motor cannot balance the other motors and the craft will flip and fall down.
I had an some what similar experience, that, after gentle manual take off, the craft launched off in a funny angle tryin to do loops, I managed to save the craft (by luck and quick reaction) by reducing throttle to about half, presumably causing the defective arm to move back from the twisted position to a more normal position, and craft steadied itself and I was able to land. After landing, I could see one arm was a bit flexible, with some migration cracks coming away from the motor. Since then I have strengthened the plastic in the area around the motors with carbon fibers and epoxy, (with a sanding of the plastic to give good adhesion) and had no problems since.
If you could check your craft to see if you had and plastic cracking from the motor on any arms, it could possible endorse my view on plastic cracking.

 

[ArnoldLeVine]

I suspect that the new battery was not completely locked in and disconnected.

 

[captainmilehigh]

When you shutdown the drone to swap batteries, did you do a complete shutdown and restart with the app and the RC also?

....or did you just swap out the drone battery, restart it, and press auto takeoff on the app?

*anytime I've had issues like that is when I did NOT do a complete shutdown, then a complete restart (R/C,App,Drone) after a quick drone battery change*

 

[CR125Honda]

Not sure if this helps but looks to me like 4 red lights. If the battery detached, I'd assume there wouldn't be any lights ??
Googled 4 red lights on a phantom 4. There's a bit of conversation on the subject.

 

[Mikevipe]

When you shutdown the drone to swap batteries, did you do a complete shutdown and restart with the app and the RC also?

....or did you just swap out the drone battery, restart it, and press auto takeoff on the app?

*anytime I've had issues like that is when I did NOT do a complete shutdown, then a complete restart (R/C,App,Drone) after a quick drone battery change*

I swapped the battery booted up and waited for the app to connect and give the the home point has been set audio cue. I have done this hundreds of times prior without issue.

The battery did not detach until it hit the ground you can see it in slow motion ejecting when it hits.

If you look in the video I stepped back immediately after touching the take off and hover button as the propellors were spinning much faster than I have ever heard at takeoff, like it instantly went to 100% motor speed as it attempted to take off. I tried to throttle down but it just started coming towards me and then shot off into the air and crashed. My first cue something was wrong was just how much louder it was and everything else happened so quick there was no time to do anything.

 

[Mikevipe]

Not sure if this helps but looks to me like 4 red lights. If the battery detached, I'd assume there wouldn't be any lights ??
Googled 4 red lights on a phantom 4. There's a bit of conversation on the subject.

View attachment 126265 View attachment 126266

That is an amazing catch on the lights! It would make sense as to why the controller throttle down didn't work after activating the hover take off. But puzzling as it told me the home point has been set, check it on the map.

 

[Mikevipe]

Found another thread with retrieval info . Might give a idea
Off fir a gallon of coffee after reading

Thread 'Flight log retrieval and analysis guide'

Jan 31, 2020

I posted this guide on the MavicPilots forum after the introduction of the Mavic Mini led to a significant increase in pilots asking for help diagnosing events and understanding log files. It may also be of some interest over here since most of it applies equally to other DJI equipment. While there is plenty of help and advice available on these forums, and detailed guidance and options on several other websites, I thought that perhaps a single summary of the subject might be useful. If it does prove useful then I'll try to keep it updated, either in this post or followup posts, and...

• sar104
• Replies: 8
• Forum: Phantom Crash & Flyaway Assistance

• 

Thank you, the problem is the remote and app logged nothing, I assume this would be because the communication theory you caught with the 4 lights. The aircraft logs turns out to contain no .dat files. I was able to extract it and its all encrypted or blank logs. When launching the DJI app a second time it appears the aircraft is making hundreds of entries in the flight index. I thought there should be one file per flight? Is this an indication of a malfunctioning flight controller? It has literally overwritten all 780 flight logs within the same time 19:26:00 when the aircraft was powered on again.

It is unfortunate but at this point the only thing I have is the videos. I just hate to repair the body and have it go off on its own again without knowing exactly what happened.

 

[captainmilehigh]

If you do get the bird flyable again, do a few bench test power-ups with the props OFF the drone. ......just in case it may want to wander away on its own again.

Hey, @Meta4..or @quaddamage ....what are your views on this issue above?........especially post #18 .

 

[quaddamage]

The aircraft logs turns out to contain no .dat files.

The screenshot you've pasted suggest there are .DAT files, sized 16kb to 200kb.

I was able to extract it and its all encrypted or blank logs.

The sizes are non-zero. Looks like there is some information, maybe it is just encrypted. I never had a P4 so I've no idea how to decrypt it. But the content of the logs is the same on all platforms - it includes packets with position of the aircraft (what most log readers display) but also text messages from the FC, describing what its doing. Maybe you just need a reader which converts the output to text rather than to flight path.

it appears the aircraft is making hundreds of entries in the flight index. I thought there should be one file per flight?

The logs are created by Flight Controller. So there is one entry per Flight Controller boot. If the log list is flooded, that means the FC is rebooting constantly. What is interesting in the list is that every file has different size - so the reboot happens at different moments for each try. That suggests cold (or ripped) joint somewhere which loses connection randomly due to vibrations of the drone (probably a fan is causing vibrations, but even a rising temperature of chips as they boot could be enough).

I just hate to repair the body and have it go off on its own again without knowing exactly what happened.

If the drone is still constantly rebooting, then you probably won't be able to turn the motors on again. But since you was able to show the list of logs, does that mean the rebooting stopped? The PC Assistant connects directly to the FC, so if it was rebooting, you would lose connection constantly. And any transfer of a log file would be terminated by the next reboot, giving you only a truncated/empty file, even if on the internal SD-card they have data.

 

[Meta4]

I was flying my P4 yesterday when the unthinkable happened. I had just flown a 17 minute flight which all was normal. After landing, I swapped the battery for the next flight. When I touched the take off and hover button on the screen the drone immediately took off at full speed, flipped and did a 360 at full speed, smashing right into the ground completely destroying it. Thankfully it crashed right between the cars and no outside damage was caused other than my ego haha.

Your description sounds like a classic yaw error incident, caused by starting up on a spot where magnetic interference gave the IMU false heading data..
If you can post the recorded flight data, that will likely confirm this.

To post your flight data there are a couple of options ...

1. Go to DJI Flight Log Viewer | Phantom Help
Follow the instructions there to upload your flight record from your phone or tablet.
That will give you a detailed report on the flight data.
Come back and post a link to the report it provides and someone might be able to analyse it and give you an understanding of the cause of the incident.
or
2. Just post the .txt file here
or
3. If you use Airdata, you can view the flight data on Airdata and post a link for the Airdata report

If you are using one of the controllers with an integrated screen, the txt files are to be found here:
Android\data\dji.go.v5\files\FlightRecord

 

[CR125Honda]

Could it have been as simple as a prop or prop hub failure?

If it were mine, I'd call DJI first send the drone and controller in for repair (if thats still an option). I sent one in many moons ago. They sent a replacement Obsidian V1 that looked brand new (and probably was), costs were very reasonable.
I've read some DJI drone are being held at customs, check to see if that might be an issue before doing this also.

 

[Mikevipe]

The screenshot you've pasted suggest there are .DAT files, sized 16kb to 200kb.


The sizes are non-zero. Looks like there is some information, maybe it is just encrypted. I never had a P4 so I've no idea how to decrypt it. But the content of the logs is the same on all platforms - it includes packets with position of the aircraft (what most log readers display) but also text messages from the FC, describing what its doing. Maybe you just need a reader which converts the output to text rather than to flight path.


The logs are created by Flight Controller. So there is one entry per Flight Controller boot. If the log list is flooded, that means the FC is rebooting constantly. What is interesting in the list is that every file has different size - so the reboot happens at different moments for each try. That suggests cold (or ripped) joint somewhere which loses connection randomly due to vibrations of the drone (probably a fan is causing vibrations, but even a rising temperature of chips as they boot could be enough).


If the drone is still constantly rebooting, then you probably won't be able to turn the motors on again. But since you was able to show the list of logs, does that mean the rebooting stopped? The PC Assistant connects directly to the FC, so if it was rebooting, you would lose connection constantly. And any transfer of a log file would be terminated by the next reboot, giving you only a truncated/empty file, even if on the internal SD-card they have data.

Thank you quad, I am currently trying to rebuild the aircraft, would you know which of the internal boards need to be replaced?

I believe the logs are being created non stop when the drone is powered on, I then plug it into the PC, the DJI program takes about 3-4 minutes to finally connect to the drone where it then prompts that it will put the drone into a specific mode to pull the logs, I am guessing when it is placed into this mode is when it stops creating new logs.

Meta4: The remote had only an empty file for the flight time/date of the crash. I used the DatCon to extract the logs from the drone and there are no additional .dat files inside. Only other encrypted files. When loaded into the log viewer in the DJI app they are all empty with no data.

I am guessing with the 4 red lights there must have been some sort of hardware failure. I am not sure about the magnetic interference but I guess its possible something in the area changed. In the past in other areas I have seen the interference warning, but at my home I have never seen it and have launched from that spot hundreds of times prior.

Unfortunately with the controller log being empty and the aircraft overwriting everything over and over I am left only with the video.

 

[Lakotah]

I have a 4 Pro for sale if your interested. Its in perfect condition

Thread 'FS: Phantom 4 Pro with Accessories'

Dec 14, 2024

DJI Phantom 4 Pro - Excellent condition
No damage.
SKB Hard case
Drone
Controller
3 sets of Rotors ( 2 regular set, 1 quiet set)
Charger
3 batteries
Gimbal support
4 Polar Pro lens filters
2 sets of antenna amplifiers

$1200 obo Reasonable offers only
Would like local pick up but if you want it shipped, you pay shipping and insurance.

Thanks….

• Lakotah
• Replies: 0
• Forum: Classifieds