Hi!

Today I have crashed my DJI FPV for the first time. One of the rear arms is broken, but it seems that can be fixed by replacing it. The thing that drives me crazy, is the cause of the crash?

It happened this afternoon in the RC airfield I fly. I was trying to chase and record, a fixed wing aircract with my drone. I was hovering close to the ground, waiting for the aircraft to take off. The drone was on manual mode. The wind was blowing strong, shaking the drone, the horizon looked tilted on the goggles. I was trying to click the record button to no avail, and all of the sudden the drone fell to the ground.

Afterwards, I though that perhaps the drone entered failsafe mode unadvertently? However at home I checked and failsafe mode was off. Then I thought that perhaps when trying to click the record button I clicked something else? There was a while since I last flew. I did not wanted to click the record button on the goggles, to avoid getting my hand off the control, to be able to fight the wind. Perhaps I clicked the panic button? But if so, the drone would have entered into hover mode. It is strange that the drone broke an arm but the props are all fine?

I have watched the last 30 seconds of flight, before the crash on the goggles. I start to hover low, to have the fixed wing pilot in sight. When I switch to manual, the drone starts to shake because of the wind. Then all of the sudden the drone climbs fast, and the video stops. There is some video footage, when the drone is on the ground. But it is strange, that the fall is not recorded. It seems as if the drone entered faisafe mode, seems like the engines stopped? That is perhaps why, the props are intact?

I would be very thankful, if someone could analize the flight log;

https://drive.google.com/file/d/ ... 0u/view?usp=sharing

Thanks in advance for your help! I hope that we all can learn from my crash.

Cheers,

Oriol

That .DAT was created using DJI Assistant 2. Unfortunately the extracted .DATs (FLY044.DAT) will be encrypted.

An unencrypted .DAT can be obtained from the Fly App using the method described here

https://fpvdronepilots.com/threads/dat-available.4225/#post-35016

Be sure to disable synching to DJI before transferring the .DAT to the Fly App.

If the Fly App was connected to the goggles during this flight then the first step where the .DAT is transferred to the Fly App can be bypassed.

Please note that this is the only way to get an unencrypted .DAT. Using DJI Assistant 2 will only yield an encrypted .DAT.

Hi there. Thank you for reaching out and we're sorry for the incident that happened on the unit. I'm afraid that you may consider sending the unit in for a proper diagnosis. You can contact our support team to start up a ticket at https://www.dji.com/support . Also, the warranty can be applied depending on the outcome of the damage assessment including the warranty period of your unit. Thank you for your understanding and support.

BudWalker Posted at 4-9 14:48
That .DAT was created using DJI Assistant 2. Unfortunately the extracted .DATs (FLY044.DAT) will be encrypted.

An unencrypted .DAT can be obtained from the Fly App using the method described here

Thanks BudWalker for your assistance!

Thinking about how all happened, I was considering a possible interference with another radio transmissor, as a possible explanation. Because when the drone crashed, it was not responding to my inputs. Although the DJI FPV/Mavic manual states that it is possible to fly with other drones, I have red on the forum that interferences with other drones nearby might happen. While flying I have experienced interferences on the goggles, whith another DJI drone on the same airfield.

The hypotesis of a radio issue has been confirmed. I have opened the APP, and I have seen a video of the crash. At min 7:28 there is a warning of radio transmissor loss.

As I recall the drone ceased to respond and sarted to drift. Then it started to climb and fell to the ground. I assume that by being close to a non flying zone, the RC airfield is located close to an airport. The software forced a failsafe to avoid the risk of an aircraft collision?

The link to the flight log is;
https://www.phantomhelp.com/logviewer/25WQ50VC3JHG4QF2PF4U/

By reading the flight log there is an unspecific warning at 7:28. On the APP video of the flight log, it reads radio transmissor lost. Then there are several warnings of cell deviation. I assume the cell deviation, is related to the radio transmissor issue, but I do not know what this implies?

I believe that the only fix that the drone needs, is to replace the arm. Because when I start it the drone, there are no warnings on the goggles. The lesson I have learned from the incident is to avoid flying with other drones. The bad news is that this implies, not flying my DJI FPV on the RC airfield, which is the only spot in where is legal to fly nearby.

Any input regarding the flight log would be greatly appreciated!

Cheers,

Oriol

DJI Paladin Posted at 4-9 19:08
Hi there. Thank you for reaching out and we're sorry for the incident that happened on the unit. I'm afraid that you may consider sending the unit in for a proper diagnosis. You can contact our support team to start up a ticket at https://www.dji.com/support . Also, the warranty can be applied depending on the outcome of the damage assessment including the warranty period of your unit. Thank you for your understanding and support.

Thanks DJI Paladin!

This has been my first crash. I was worried that the drone could not be fixed.

Perhaps I am able to fix the drone by myself, by replacing the broken leg. In any case, does a crash reparation, that results from a radio transmission loss, is covered by the warranty period?

I received the DJI FPV drone on 28 may 2021, less than two years ago.


Cheers,

Oriol

fans9bd004c9 Posted at 4-10 12:54
Thanks BudWalker for your assistance!

Thinking about how all happened, I was considering a possible interference with another radio transmissor, as a possible explanation. Because when the drone crashed, it was not responding to my inputs. Although the DJI FPV/Mavic manual states that it is possible to fly with other drones, I have red on the forum that interferences with other drones nearby might happen. While flying I have experienced interferences on the goggles, whith another DJI drone on the same airfield.

The submitted log doesn't match your description of the flight. There was no loss of uplink or downlink. The FPV  made an uneventful and controlled landing. The next flight would match the FLY044.DAT you submitted earlier.

If there was interference from another aircraft it would have to be some kind of DJI product. But, the result would be that your FPV would hover and not move. Any interference would not result in the FPV climbing fast and then falling.

Can you submit the next flight? Better yet can you submit the .DAT by using the method I referenced above? It will have a name FLY***-044-20230409HHMMSS.DAT

BudWalker Posted at 4-10 13:27
The submitted log doesn't match your description of the flight. There was no loss of uplink or downlink. The FPV  made an uneventful and controlled landing. The next flight would match the FLY044.DAT you submitted earlier.

If there was interference from another aircraft it would have to be some kind of DJI product. But, the result would be that your FPV would hover and not move. Any interference would not result in the FPV climbing fast and then falling.

Hi Budwalker, Thanks a lot for your help!

Sorry for my mistake in posting the wrong log. This link below is that of the last flight in my files. When you look at the flight track over the terrain, it seems as if I have landed. But the last recorded coordinates are 61ft high, not 0.

I have seen the last 30 seconds of flight and the footage stops before the drone crashes. There is a warning that reads transmission lost on the goggles. This warning does not show off on the Phantom flight log. According to some whitnesses the drone literally fell to the ground. I was lucky that the drone fell in the grass, not in the pavement.

https://www.phantomhelp.com/logviewer/5HMIHQO5F899FG8W15WO/

In the last flight prior to the crash, there is a transmission loss warning on the DJI app. I did not noticed it while flying, because I was focused on the flight.

Cheers,

Oriol

fans9bd004c9 Posted at 4-10 15:56
Hi Budwalker, Thanks a lot for your help!

Sorry for my mistake in posting the wrong log. This link below is that of the last flight in my files. When you look at the flight track over the terrain, it seems as if I have landed. But the last recorded coordinates are 61ft high, not 0.

It's difficult to tell where the log matches the description that the FPV started to ascend and then dropped. One possibilty is that at 34.6 secs throttle was increased and the FPV began to ascend. At about 37.7 secs throttle was reduced to full negative and the FPV began to descend. AT the very end of the log the OSD:isMotorOn went to False indicating the motors had stopped. And at this point the ascent rate started to drop also. If, for some reason, the Flight Controller had determined the flight was terminated that would explain why the log stopped, and video stopped.



The .DAT may help determine if the Flight Controller had determmined if the flight was terminated

BudWalker Posted at 4-11 06:46
It's difficult to tell where the log matches the description that the FPV started to ascend and then dropped. One possibilty is that at 34.6 secs throttle was increased and the FPV began to ascend. At about 37.7 secs throttle was reduced to full negative and the FPV began to descend. AT the very end of the log the OSD:isMotorOn went to False indicating the motors had stopped. And at this point the ascent rate started to drop also. If, for some reason, the Flight Controller had determined the flight was terminated that would explain why the log stopped, and video stopped.

[view_image]

Hi BudWalker, thanks again for your help!

I have analized the 044.DAT file with CSV, but I do not understand the code? It seems that something malfunctioned, because there are many errors listed, but I do not know how to tell what exactly? Using the .DAT file with CSV the resulting flight path of the drone is complete. Whereas on the DJI FLY app, the flight path ends when the radio transmission is lost.

Here below is the link with the .DAT file, plus a screenshot of the DJI FLY app, with a radio transmission loss warning on a prior flight.

https://drive.google.com/file/d/19-ScUA4mf-XlRa1PHL2mq6mfCQpHKu8s/view?usp=sharing

It would be very kind, if you can analize the flight log. To determine what went wrong?

Cheers,

Oriol

fans9bd004c9 Posted at 4-10 13:01
Thanks DJI Paladin!

This has been my first crash. I was worried that the drone could not be fixed.

Thank you for your response. We don't have any guarantee that a DIY repair will totally fix the unit or return it to its normal shape. Thus, we recommend sending it to us for proper testing. You may contact the link that I have sent above to process a repair request. Thank you for your understanding and support.

fans9bd004c9 Posted at 4-11 12:19
Hi BudWalker, thanks again for your help!

I have analized the 044.DAT file with CSV, but I do not understand the code? It seems that something malfunctioned, because there are many errors listed, but I do not know how to tell what exactly? Using the .DAT file with CSV the resulting flight path of the drone is complete. Whereas on the DJI FLY app, the flight path ends when the radio transmission is lost.

At 37.717 secs all motors were commanded to stop which caused the rapid descent from a height of 16.7 meters.


It's not clear, to me at least, why the motors were commanded to stop. The eventLog stream does offer some clues. Relying on the eventLog stream is problematical because entries can be ambiguous, vague, etc. That said, here are the entries when the motors were turned off.



Clearly, the FPV was not on the ground at 37.541 secs

BudWalker Posted at 4-12 06:48
At 37.717 secs all motors were commanded to stop which caused the rapid descent from a height of 16.7 meters.

[view_image]

Thanks Budwalker for your insight!

I contacted DJI suppport, and I will ship them the drone for a proper diagnose, and repair. If they provide me some explanation for the crash. I will post it in here, so that it might help others.

Happy flights,

Oriol

DJI Paladin Posted at 4-12 03:10
Thank you for your response. We don't have any guarantee that a DIY repair will totally fix the unit or return it to its normal shape. Thus, we recommend sending it to us for proper testing. You may contact the link that I have sent above to process a repair request. Thank you for your understanding and support.

Thanks DJI Paladin for your assistance!

The drone is still under warranty. Therefore I will send it to a service center for a proper diagnose and repair.

Cheers,

Oriol

fans9bd004c9 Posted at 4-13 12:31
Thanks DJI Paladin for your assistance!

The drone is still under warranty. Therefore I will send it to a service center for a proper diagnose and repair.

You are most welcome, Oriol. Hoping that you will get your fully working drop asap. Should you have other inquiries, please don't hesitate to reach us. Thank you for your valued support!

Hi everyone!

I send the drone to a DJI service center. I have received the following quotation message with an explanation of the cause of the accident;

"Remark

MC SN: 37QBJ4FBD104L5 BAT SN: 37WPJ57AA103GP Flight Date: 2023-04-10 00:12:00 GMT+8 FLY044 1. the aircraft worked
under Manual mode 2. Flight Time T=100.38s, Relative Height H=18.60m, Distance to Home Point D=44.34m, the pilot pressed the Stop\Start button twice and the motors stopped, then the aircraft fell off from the air. Conclusion: The incident was caused by non-manufacturing
factors. Therefore, it is concluded to customer responsibility. NO WARRANTY: Physical damage. No liquid damage. Rear Left Aircraft Arm Module damaged. IN WARRANTY: Vision Sensor Board to E1E Core Board Flexible Flat Cable malfunctioned. After repair/replacement,
faulty unit or parts will not be returned. To provide you a better after-sales service experience, 50% discount of the repair service fee has been offered for you in this quotation."

I still do not understand, the cause of the crash?
According to the manual, when you click the stop button, the aircraft enters into hover mode; the motors do not stop all of the sudden. The failsafe feature was disabled on my drone. So why did the motors stopped?

I too have received a photo, of a self diagnose performed by the drone.

https://drive.google.com/file/d/ ... view?usp=share_link

The first issue on the list above is remote disconnected. I send the remote and the goggles to make sure everything was functioning properly. If the remote became disconnected, it is not because of clicking unadvertently the emergency brake/panic button.

According to the quotation the accident was my fault, and albeit I am offered a discount. I do not understand why it is my fault, that the connection with the remote was interrupted?

I am not trying to fight, I am only trying to understand what went wrong? So that this accident does not happen to anybody else.
I will try to contact by telephone the service center, to find out more.

Cheers,

Oriol

Dude - I want to come fly at that field - Nice fly spot - paved runway and all. I bring my 30% yak AND my FPV.

fans9bd004c9 Posted at 4-26 12:02
Hi everyone!

I send the drone to a DJI service center. I have received the following quotation message with an explanation of the cause of the accident;

"Flight Time T=100.38s, Relative Height H=18.60m, Distance to Home Point D=44.34m, the pilot pressed the Stop\Start button twice"


Is it possible that you pressed the stop button twice? Possibly pressing it once and, not seeing an immediate reaction, pressed it again?

Nitro-Tom Posted at 4-26 14:20
Dude - I want to come fly at that field - Nice fly spot - paved runway and all. I bring my 30% yak AND my FPV.

Yes, it is a wonderful field for flying fixed wing aircrafts! I am looking forward to learn to fly those. I entered into the hobby with  Mavic. I learned to fly Acro with the DJI FPV. DIY stuff is fun too!

BudWalker Posted at 4-27 06:25
"Flight Time T=100.38s, Relative Height H=18.60m, Distance to Home Point D=44.34m, the pilot pressed the Stop\Start button twice"

You are right Budwalker,

I pressed the panic button twice, and the drone went down. Albeit I read the manual thoroughly, when I bought the drone. I forgot that pressing the panic button twice, cut the engines!

Mistery solved. It was my mistake, not a drone malfunction.

Thanks a lot for your advice in analizing the flight! It is good to learn from one's mistakes.

Cheers,

Oriol

plus one on that my friend - I almost lost my Avata a few weeks ago with an errant RTH - the battery got low - and of course I forgot to set max distance, RTH Altitude and such before the first flight in my new area and on the first flight when I dropped to Low battery it came home alright - missed a light pole by inches and I could not remember the RTH button position so I was turning on and off the camera :-)

I use the FPV Controller2 so the RTH and or cancel RTH is on the LEFT - My other left! da..... i also made a printed card and took a pic on my phone to remind me what I programed the S1 button for. one click to turn on ESC Beeping and 2 taps for turtle mode. With all these options its no wonder we make the occasional mistake,

Don't look back on the broken arm, have DJI Care refresh on your birds and keep on flying!

I made the exact same mistake you made - it happens - i just got lucky and missed the poll by inches as I watched in HD horror.......

Hi!

I got my drone fixed from DJI. I had an issue activating the drone with my smartphone, but I tried a second time and everything went fine. Now I need to go out and fly it.

Thanks so much for taking time to share your advice.

Happy flights!

Oriol