2 Crashes in 4 days

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Hello everyone,

I'm working in Saudi arabia on a mapping mission in the desert.

In the past 4 days, I crashed a phantom 4 and a brand new phantom 4 pro V2.0 flying the same area.

I was working with android device galaxy tab A7 and dronedeploy.

I worked previously on this site earlier this year with no problem even with the heat.

I checked the flight logs on dji flight viewer.

First crash : no alarm, the drone just dropped on the ground with 35% battery (brand new battery)

Second crash : the drone start dropping altitude and "GPS position mismatch" is appearing in the flight log. And the drone just dropped on the ground. (brand new battery, different from the first crash)

Both drone are destroyed...

Do you guys think it could be related to the heat? in that case wouldnt there be a "overheating" message in the flight log? For my previous job there I used to cool down the drone in the car before every flight but this time I couldn't do it.

Could this be a gps related issue? Interferences in this specific area of the site? It's complete desert.

Thank you guys for your help!
 
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What was the air temperature? You can probably assume the ground temperature while it sat there waiting to launch would be much hotter than the ambient air in a desert setting. According to DJI, operating temp range of a Phantom 4 Pro is 32° to 104°F (0° to 40°C). I'm sure under certain conditions a desert floor could reach 120F+ in the sun. That may have been a factor that the electronics just couldn't handle, especially the batteries. But just a guess. You did mention cooling it off a bit before flying on previous missions that were successful. However, I don't know what the typical desert temps are at this time of year there.
 
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Meta4

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Do you guys think it could be related to the heat? in that case wouldnt there be a "overheating" message in the flight log?
Could this be a gps related issue? Interferences in this specific area of the site? It's complete desert.
Interference or loss of GPS doesn't make a drone stop flying and Position NoMatch messages are often meaningless.
Guessing is unlikely to reveal what actually happened, but the recorded flight data might or help eliminate some guesses.

In your phone there will be a folder called DroneDeployLogs.
It will have a number of files with names like this:
620dacd9fd94da3aece77b01_2022-02-17-121238-945_2022-02-17-121800-597.log

If you sort those by data order and work out which are from the incidents, post those here and someone might be able to investigate and see what they show.
 
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here are both flight logs from both crashes.

I put the .log file i could retrieve in a zip file so i could post it here

maybe somebody can find some clues on what happened there.

Thanks a lot for your help guys!
 

Attachments

  • DJIFlightRecord_2022-03-23_[13-28-06].txt
    1.5 MB · Views: 28
  • DJIFlightRecord_2022-03-25_[14-13-26].txt
    2.4 MB · Views: 22
  • 2022_03_25_13_49_19.zip
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Meta4

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here are both flight logs from both crashes.
The flight dated 25/3
The drone was towards the end of an E-W run when it rolled hard to the right, pitched backwards, started spinning fast clockwise and losing height.
It tumbled and spiralled to the ground.
This indicates loss of the rear right prop or motor.

23/3
Trouble started at 9:05.7 during a N-S run.
The drone rolled hard to the right, tipped back, rotated clockwise and started losing height.
It tumbled and spiralled to the ground.
This indicates loss of the rear right prop or motor.

It's a strange coincidence to have two phantoms have the same issue on the same prop/motor.
But have a look at that motor/prop on each to see if there are any clues.
Do the motors spin freely, is the prop still attached etc?
But a missing prop isn't conclusive.
It could have come off with the impact.
 
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23/3 rear left prop (the left one when you face the battery slot) was harder to spin than the other ones

25/3 all props seem fine

I'm starting to think it could be some sand in the props. On 25/3 it happened two times that take off failed because of the wind so the drone flipped directly on the ground/sand. Or maybe there was already a prob problem on the rear side making the drone fail to take off properly.

Do you think it could be related to using Dronedeploy? both flight were made using DD.

Thanks a lot for your analysis!
 
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I did not do the vision sensors calibration on the drones.

The ground i was covering is particuarly bright because of the light reflection (white rocks).

Do you think it could be related to that?
 

PhantomWetSuits

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You might consider getting a Wet Suit to help with the Sand in the drone and in the props as well as securing the battery . We offer a nice discount for the Forum members left you a Pm.

Battery disconnecting :

Phantomrain.org
Gear to fly in the Rain /Sand
 
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Capt KO

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Sad to hear. Agree that a Large landing pad is in order but a bit too late now. Worth Care Refresh next time. Good luck.
 
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How many drones did you lose in that desert? If non it would be very unlikely to this happened twice in the same manner.
 
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If META4 didn't find the reason, it is hard to find it out at all. Particulary because of this double accident. Most probably the reason was not related to the drone .
I think the sand and the temperature had something with it. But still couldn't explain the same happened twice. That is a mystery.
 
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So we had to purchase a secondhand P4P in order to try completing our job.

It crashed as well with absolutely no warning. 80% battery. flight lasted 4 min then I lost RC signal and it just fell from the sky...

anybody has any explanations on this?

A few months back I worked on the same site with higher heat and had no problem whatsoever with the first crashed drone.

The only things changed since then are the android version, an additional battery hub (not dji) and new batteries.

Thanks for your help
 

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  • DJIFlightRecord_2022-04-01_[11-53-30].txt
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Meta4

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It crashed as well with absolutely no warning. 80% battery. flight lasted 4 min then I lost RC signal and it just fell from the sky...
anybody has any explanations on this?
Battery temperature was normal at 113° for the flight.
The drone was flying normally on a short southward leg and started to turn west to start another long run.
And the data just stops at 284.5 seconds.
Losing signal doesn't cause drones to fall from the sky.
But loss of signal is a symptom of the drone losing power.
The most likely explanation would be a battery dislodging enough to disrupt power to the drone.
 
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Thank you for your answer, that would have been my first guess too but I really really doubt that. I always double check the battery is well lodged in when i put a new battery in, it's part of my routine checks and especially after the two first crashes...
Retrieving the crashed drone, the battery was still lodged in securely...
 

Meta4

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Thank you for your answer, that would have been my first guess too but I really really doubt that. I always double check the battery is well lodged in when i put a new battery in, it's part of my routine checks and especially after the two first crashes...
Retrieving the crashed drone, the battery was still lodged in securely...
We can't be sure of the cause of the loss of power, but the cause of the fall to the ground was loss of power.
Unfortunately in loss of power incidents, that also means a loss of data so it's hard to tell anything more.
 

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