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Phantom 4 drone suddenly drops and is nearly seriously damaged

Hi

We have flown our DJI Phantom 4 several times successfully with Pix4D capture until yesterday. The first flight yesterday was successful however During a second flight over a mountainous area the drone suddenly lost altitude 120m up and rapidly dropped to the top of the mountain. The mission was still in progress and 90% complete. Luckily the drone soft landed into dense vegetation otherwise the drone would have been seriously damaged or destroyed. We checked the drone using DJI own software and there was no problems reported. We did a test flight using DJI go app and the drone flew perfectly. We then tried to fly the same mission again using Pix4D capture and the drone exactly repeated the same problem and lost altitude at the exact same point in the mission. Again very luckily the drone survived the landing. On lookers observed that the drone came down quite quickly. The battery was also ejected from the drone after it landed indicating it did hit with some force. We have not had any issues with this drone prior to yesterday.

The drone was well above the height of the top of the mountain and was around 300meters away and within VLOS. We haven’t experienced this problem before. The drone was flying in the direction towards the mountain. We have done testing and diagnostics with the drone and no problems or errors are reported by DJI. The drone is in excellent health.

We were also unable to retrieve any logs from the drone as none appear to have been recorded whilst the drone was being flown using Pix4D capture.Does Pix4D capture store any of its own flight logs to help identify what the problem is?

We haven’t observed any problems flying the drone using DJI Go only with Pix4D capture.

 

 

Hello Nathan,

We are sorry about the situations you have experienced with your drone.

To be able to troubleshoot efficiently, I would have several questions:

  • What is your configuration? (drone, camera, mobile device) Are you using the Android or iOS version of Pix4Dcapture?
  • Are you updated with latest drone firmware and application version?
  • When you say that the first flight was successful and that troubles came with the second flight, were you flying in the exact same conditions (similar settings, same grid, same location…)?
  • What was the state of the battery of your drone when it happened?
  • If using iOS version of Pix4Dcapture, were you using the Safe or Fast mode to trigger picture?
  • Could it be related to a drone engine problem the fact that it dropped like this or the engines were still working nicely?
  • Do you know if the state of Pix4Dcapture changed when flying the mission? For example, changing from “on the mission” to “landing”.
  • Have you checked that no settings in DJI GO 4 can induce the behavior you mentioned? For example behavior of the drone when the connection is lost…
  • Also, Can it be related to the fact that the terrain was mountainous? Pix4Dcapture and the drone is not taking into account the terrain elevation changes when flying a grid mission. It will take the takeoff point as 0m reference.

Also, I can recommend you to have a look at the following article for our basic checks and troubleshooting steps.

Best,

 

Nathan, 

We had the same thing happen here.

Phantom 4 Pro, worked perfectly fine for the 6 months prior.

Then one day, a month and a half ago, we created a 2d polygon mission with the Pix4d capture app and sent the drone out.

On the way back it dropped from 100 meters.

Ours wasn’t lucky enough to survive the crash though.

Using DJI assistant 2, I looked for the logs and for some reason, only one dat file was there. No controller input file.

DJI, being the crooks they are, just informed us yesterday, after having the wreckage for a month, that they would not cover the repairs under warranty, yet they can’t say what caused the crash, nor why the log wasn’t created.

We buy their products because they are cheap enough to be considered throwaways here.

But for a company to not be able to explain why their product behaved the way it did, nor honor their warranty, is pretty shameful.

Please post back here with what you find out because our situations sound very similar.

 

 

 

What is your configuration? (drone, camera, mobile device) Are you using the Android or iOS version of Pix4Dcapture?

Phantom 4 with supplied camera and iPad mini running latest version of iOS and latest version of Pix4DCapture

  • Are you updated with latest drone firmware and application version?

Yes - latest updates are always applied to the drone prior to each flight.

  • When you say that the first flight was successful and that troubles came with the second flight, were you flying in the exact same conditions (similar settings, same grid, same location…)?

The second mission was duplicated from the first mission which flew correctly and this seonc mission had a different grid in 2D polygon mission which was rotated around the middle axis.

  • What was the state of the battery of your drone when it happened?

Battery was at 76% battery level.

  • If using iOS version of Pix4Dcapture, were you using the Safe or Fast mode to trigger picture?

Not sure but the drone speed was set to Normal

  • Could it be related to a drone engine problem the fact that it dropped like this or the engines were still working nicely?

The drone has had no previous problems or crashes and no issues with the motors. The drone is in excellent condition.

  • Do you know if the state of Pix4Dcapture changed when flying the mission? For example, changing from “on the mission” to “landing”.

Mission status did not change and it did not change to landing.

  • Have you checked that no settings in DJI GO 4 can induce the behavior you mentioned? For example behavior of the drone when the connection is lost…

No settings were changed in DJI GO 4 that could have caused a problem we encountered. We have flown the drone using earlier versions of Pix4D with no problems up until now. If the signal was lost we would have heard an audible beep and the drone was set to return to home which it did not.

  • Also, Can it be related to the fact that the terrain was mountainous? Pix4Dcapture and the drone is not taking into account the terrain elevation changes when flying a grid mission. It will take the takeoff point as 0m reference.

The mission was set to an elevation of 120m and this was higher than the nearby mountain. The drone flew over the mountain a number of times as part of the 2D flight plan and had nearly completed the mission when the drone descended immediately without any warning over the last section of the mountain. The last photo obtained from the drone shows that there was still sufifcient height under the drone. It was observed by three people that the drone was clear of the mountain and it did not hit the mountain. There was no loss in signal, GPS was excellent as we had around 16 sateliites and we had line of sight at all times with the drone. We have flown further and with less GPS satellites on previous missions with no problems until now.

Hello Nathan,

Thank you for all the answers and information provided.

In a general way, the drone is actually responsible for not destroying itself and going out of control. Pix4Dcapture is a third-party application and it can not override the fail-safe behavior of the drone.

Normally taking over manual control should prevent incidents from happening. Were you able to take over manual control by moving the remote controller joysticks, changing flight modes or by pressing the return-to-home (RTH) button? You can have a look at our article on how to interrupt a mission when an unexpected behavior occurs here.

However, we can have a look at the Pix4Dcapture logs to investigate further the behavior you encountered. I will create a ticket for that.

Best regards,