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P3P Falls from Sky for No Reason

Discussion in 'Pro/Adv Discussion' started by achoe, Sep 12, 2016.

  1. achoe

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    Hi,

    I went on vacation to Norway a few weeks back and had a traumatic experience... I chose Norway because I wanted to film its beautiful fjords with my P3P, and 3 minutes into my first flight in Norway, my P3P fell from the sky for no reason. There wasn't any wind, any obstacles, and it was flying fine for 3 minutes until it just started to spin around and fell into the lake... I am assuming it was some sort of engine malfunction for one of the engines. As you will be able to see in the attached video, it was a huge lake and I was not able to retrieve my P3P. I've flown my P3P for over a year in various situations and never had an incident like this. I have a video of the entire flight as well as the flight log retrieved from my phone, so I am hoping to prove that it's not my fault and possibly get DJI to give me a new phantom or some sort of compensation.

    Could any experts out there help me prove it is not my fault? I have no idea how to read the flight log and would love to get some advice on how to proceed with DJI.

    Thank you in advance.

    [Edit 1]: i tried uploading an excel version of the flight log for your convenience (both csv and xls), but the website won't let me upload. Please let me know if anyone needs an excel version, and I'd be happy to send it over!

     

    Attached Files:

    #1 achoe, Sep 12, 2016
    Last edited: Sep 12, 2016
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  2. 80Aerial

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    Sorry to hear about the loss of your P3. Very unfortunate situation indeed.
    Without looking at your flight log, want to rule out the obvious first. Did you perform a standard pre-flight check of the copter? The flight looked nice and smooth up until the end just before it plummeted into the water, and it looks to me like either a prop came off or your lost a motor or an ESC. I'm guessing one of the later...again, just from the look of it in the video. A bird strike would've been quick and I didn't notice any birds in the video before the incident. Did see some rain starting to fall, but not enough where it would've caused that to happen.

    Hopefully someone can look at your logs and offer some firm assessment as to why your bird took a death plunge into the lake.
     
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  3. achoe

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    80Aerial,

    Yes, I did the standard-checks. It definitely wasn't the prop falling off (I always make sure they are tight). It wasn't an ESC (in which case, I think P3P should have just fallen straight down as opposed to spinning like it is in the video). It wasn't a bird strike either, as I had my LOS to the drone and didn't see birds coming. And it wasn't raining either as you can see from the video....

    As I've said, I flew P3P for over a year without a single crash and I'm pretty experienced when it comes to flights. It really is a mystery to me why it just fell like that. Thanks for your thoughts!
     
  4. 80Aerial

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    Thought I saw some raindrops on the image starting at around 3:09. There's definitely some moisture spots visible on the lens at 3:15. Again, not enough to cause or explain what happened.

    That initial "glitch" at 3:19 and again at 3:22...was that you course-correcting? Did you initiate those sudden movements? If not, then those points in time probably indicate when the issue started; they were sudden and extreme enough to cause the arm and prop to significantly dip into the picture. That happened to me today for the first time (although to a much lesser extent) and the cause was a sudden gust of wind at about 145'.

    Also, the copter seemed to fall in a spiraling motion rather than just drop, which to me implies the loss of one of the four motors somehow. Again, I'm not an expert by any means so I hope someone with log-reading experience can help solve this mystery.
     
  5. 80Aerial

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  6. Mark The Droner

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    The left prop arm seems to be shaking/shuddering more than normal at the two minute mark....

    Sorry for your loss
     
  7. msinger

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  8. HWCM

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    If you have had it for over a year, it is out of warranty and DJI will not cover it or help with a replacement.

     
  9. Quadcopterpilot

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    At 4m 12.6s you got compass error and the bird switched to Atti mode.
    Could be a prop, a motor or electronic failure.


    Sent from my iPad using PhantomPilots
     
  10. ftomas

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    In most EU Countries the warranty is 2 years....
     
  11. HWCM

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    Really? That is great.
     
  12. chazz

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    I'm trying to understand this...Is a high cell deviation a sign of a missing prop? Right before it started falling the log records a high deviation at about 4m12s...Also at 0M 35.6s at the end of the first high cell deviation it skips aprox 5 seconds in the Log...Is that typical? If i didn't trust what you are saying about the missing prop I would think the battery caused this issue...But I really don't know what I'm looking at...
     
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  13. HWCM

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    Cell deviation, I believe, is a sign of a cell going bad the battery pack. The P3 battery is a 4S battery, or a 4 cell battery. If a cell goes bad the battery is not outputting the full voltage. Deviations are normal because all cells are not going to be outputting the exact same voltage at any given time, but if the deviation is consistent or many times over a short period of time, you should discontinue using that battery.

     
  14. achoe

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    Could this mean that it was a battery issue? I actually bought a new battery right before leaving for Norway (yes, this was bought in the U.S. so I don't have the 2 year EU warranty someone mentioned above). This was actually the first time I used that new battery, so if it was a bad battery, it may explain exactly why it fell on its first flight..... Would it be possible to find more evidence that it was the battery?
     
  15. LeonW

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  16. Mark The Droner

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    I think what chazz is saying is his battery, as a whole - not in a cell, jumped up in voltage. All four cells jumped in voltage at the 4 min 8 second mark. So he theorizes that this is why msinger is possibly speculating a prop flew off - at that point (because the draw on the battery was suddenly reduced resulting in the voltage jump)...
     
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  17. LeonW

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    Non composite hubs have been known to unwind themselves due to the p3's active braking is all..

    Sent from my SM-G935F using PhantomPilots mobile app
     
  18. chazz

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    It looks like Cell 1 in the battery has a high deviation (when I say high I mean its red in the log and assuming that means high) at 33.4s which caused it to miss 5 seconds of recording the log and at 4m12.6s which was right before it fell...Another thing I noticed is you started with 96% charge and I hear that may cause issues..Was the battery sitting for a while after you charged it and is it possible it started the discharging process? I really don't know if it was the battery I'm just trying to understand and maybe learn something in the process...
     
  19. chazz

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    Yes i could see how a voltage increase would mean a missing prop but honestly I don't know how much of an increase it would be...

    3.625V 3.672V 3.668V 3.586V
    to this
    3.777V 3.826V 3.806V 3.743V

    Is that enough to consider it a prop?
     
  20. HWCM

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    The Phantom 3 does not have active braking.
    That's not how it works. Props won't fly off.

    Sent from my HTC6535LVW using PhantomPilots mobile app
     
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