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P3A crashed on third flight, please help analyse the cause

Discussion in 'Pro/Adv Discussion' started by Otto Henry, Dec 26, 2015.

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  1. Otto Henry

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    Hi there

    After almost 1 year without a drone I finally bought the P3A ahead of a 6 week trip to Dominican Republic. I used to own a P2 and I absolutely loved it, I probably logged >100 flights and got a few nice videos. I never had any serious issues and I eventually sold the drone to a friend when my work/family situation no longer allowed me a lot of free time.

    I was very impressed with the improvements made to the P3A. But, already on my third flight I experienced something that never happened even after 100 flights with my P2 - it fell down from the sky completely without warning! I was only a minute into the flight (plenty of satellites and a newly calibrated compass) when suddenly the quad started to flip over. It was about 20 meters up in the air and came down hard - shell deformed and cracked, two twisted motors, dented camera and trashed gimbal.

    I have attached the log file and the video (recovered from the Go app, video from SD-card won't play) and would love any input you guys might have to what could have caused the crash. I have already bought a new one and I really would like to avoid this happening again...

    Also, I tried to e-mail DJI but even after almost 2 weeks I have gotten no response. Anyone with similar experience who can tell me how I best get in contact with them?

    Log file



    Thanks in advance!
    Marcus
     
  2. alokbhargava

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    Bird can suddenly fall from the sky if battery died or hit another object. I can't think of any other reason.
     
  3. msinger

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    The battery did not die though -- otherwise, the video would have stopped before it started to tumble. I'm assuming either the Phantom struck something or a prop fell off.
     
    alokbhargava likes this.
  4. TrynFlyn

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    Don't see a prop on the one arm showing in the video.
     
  5. alokbhargava

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    yes singer is right, battery was on and thus camera was recording.

    I also don't see prop on one arm.
     
  6. Luap

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    Can you post the DAT file ?
     
  7. TheRealNick

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    I think the .dat file is above the video...I can not check it for awhile.

    From just the video it looks like something hit it to me....it does seem like the prop is missing...
     
  8. JustinJ

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    I don't see anything that indicates a strike - what do you see that I am missing?

    I do see a missing prop though.. & direction of fall / flip in relation to loosing that prop.
     
  9. Otto Henry

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    All props were still on after it crashed and motors running like crazy upside down.

    Battery 92% after the crash and i

    I was looking at it directly so I know that nothing hit the copter, at least nothing big enough to be noticed at a 30 meter distance.
     
  10. Dirby

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    you were to close to to many things.
     
  11. msinger

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    Okay. My new theory is that one of the motors stopped :)
     
  12. Otto Henry

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    I disagree. I was flying in my own backyard, the same route that I've flown several times before and never had any problem. At the moment of the crash I'm probably 5-10 meter above the closest tree.
     
  13. Otto Henry

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    I have a very strong memory of taking off 4 props. But, maybe I'm mistaken... After looking at the video in slow motion I can't see a prop on the arm that goes into the video.

    Is there any way to look at the data microsecond by microsecond and look at engine rpms? If I lost a prop mid air I would guess that would show in the data.
     
  14. Helijoc

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    I like the theory one motor stopped or perhaps the rotor was stripped. Inspect the threads on the rotors
     
  15. Otto Henry

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    How do you mean? Two rotors were unharmed, the other two smashed to pieces.
     
  16. TheRealNick

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    The video may not catch a spinning prop...

    To me the sudden movement of the video made me think maybe hit by something...the .dat file has acceleration sensors that could help.
     
  17. andy antoniou

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    You must off hit the telephone wire


    Sent from my iPhone using PhantomPilots mobile app
     
  18. Helijoc

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    Meaning the rotor in question had a cracked hub and the motor was spinning free.
     
  19. Luap

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    If you still can power on the P3 try downloading the DAT files of the day you crashed:
    This is how :
    Transfer the FLYXXX.DAT file to your computer
    1. Go to the DJI GO App and connect to the P3
    2. MC Settings -->
      select Advanced Settings Advanced Settings --> Enter flight data
      mode
    3. wait until you get a dialog telling you that the quad is
      in flight data mode.
    4. Connect a USB cable from the USB plug in the nose of the Phantom3 to your computer. This is not the USB connector on the side of the camera. Your Phantom 3 should have come with the required USB cable
    5. The data drive should mount and be available.
    6. Use the date on the FLYXXX.DAT files to pick the one you want and copy it to your computer
    7. Post them in dropbox or google drive
    Below is an example of some of the data available - including individual cell voltage, individual motor rpm etc etc. Would be a good start to analyse reason of crash
    upload_2015-12-26_23-23-24.png
     
  20. Richard W

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    He said he did not ... besides, the drone was too high for residential telephone or electrical wires, and above the tree level. Next guess ... :D