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Need help analyzing fall from the sky

Discussion in 'Pro/Adv Discussion' started by Heisnuts, Aug 13, 2016.

  1. Heisnuts

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    You always think it won't happen to you until it does. Today I was flying over the ocean just under 400 feet and then all of a sudden the bird starts tumbling and I get the dreaded "motor obstructed" message as it continued to spin out of control and then right into the ocean. Needless to say, I am pretty bummed that my 5 month old bird is no longer, but I did manage to rack up over 600 miles in that time and have fond memories with videos and pictures.

    Now, as you will see in the logs, the flight only lasted 3 minutes, the battery was at 85% at the "incident" and there were no birds and obviously no trees or buildings in the ocean. The only thing i can figure is that one of the motors either seized or the mother board failed and shut down one or more of the motors. I am at a complete loss to explain why this happened which is why I am asking if anyone here might be able to shed some light on it.

    The healthy drone report is here HealthyDrones.com - Innovative flight data analysis that matters
    and the txt file is attached to this thread too.

    Any help from any of the experts here would be really appreciated.
     

    Attached Files:

  2. Lifted Chevy

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    I hope you find out it's a failure on DJI's side so you get hooked up. Sorry for your loss.
     
  3. ElGuapo

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    Based on the flight log looks like something catastrophically happened at 3 minutes and 06 seconds of your flight when the motor was obstructed. At 3 minutes and 07 seconds the chopper lost GPS signal, at 3 minutes and 08 GPS signal was regained, at 3 minutes and 11 seconds GPS signal was lost again.

    Looks to me like a main board malfunction and you should contact DJI on this one but be nice when you do get in touch, maybe they will help get another bird. I have followed threads in this forum that when people are nice about incidents like this they replace the bird if they can determine it was internal malfunctions. Ask them to help you understand why this happened...

    I had a similar situation with one of my birds, I kept losing GPS connection and compass calibration error. I sent it to DJI to repair and they determined the main board needed to be replaced.
     
  4. nollzr

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    Has your GPS signal gone on and off before prior to this flight? Have you had any error messages prior to this flight?

    Sent from my SM-G900V using PhantomPilots mobile app
     
  5. Meta4

    Meta4 Moderator
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    At 3:06 things start to go pear-shaped.
    The compass heading, gimbal pitch and gimbal heading are all over the place indicating that the Phantom is tumbling.
    0.8 seconds later the Phantom has fallen 8 feet and you get the motor obstructed warning.
    This is an uncommon message 370 feet up and one possible explanation is that the Phantom has hit something. Perhaps a bird? Maybe motor trouble ?

    The GPS count goes down, probably due to the antenna not pointing toward the sky as the Phantom tumbles.
    In 7 seconds the Phantom falls 350 feet.
    There are no indications of problems with battery, compass or any other of the Phantom's systems.
    Contact DJI's online help and see if they can dig a little deeper into the flight record to find a little more
     
    Digdat0 likes this.
  6. Heisnuts

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    Up until 2 days ago, I had never had any GPS errors or really any mishaps or crashes. I did have to send the bird back to DJI last month for a shell replacement due to some stress cracks on one of the arms, but DJI replaced the entire shell under warranty and I have had over 75 successful flights since it has been back with no problems.

    Now the one thing that is really weird is the day before this I was flying along just under 400 ft in an entirely different location and I had the same thing happen. The bird started to tumble and I got the "motor obstructed" message and I watched in horror as the video showed the bird tumbling down to earth. However, that time the bird recovered itself and started to hover and I was able to fly back to the home point after letting it hover for a little bit to recover my composure and make sure everything seemed to be working OK again.. That time I figured it was some kind of bird strike from behind (like a hawk thinking it was prey) even though I did not see any birds and I could see from the live video nothing was in front of me and I was traveling forward. Of course when I got the bird back to the home point I checked everything. There were no signs of anything hitting the bird, no smears like feathers or feet hitting the blades, the motors all seemed like they were spinning freely and none of them were hot to the touch. Even so I recharged the batteries, waited for the bird to cool down so I could do a cold IMU calibration and then flew a few test flights over a large grassy area with no problems and no errors popping up on the screen during the flights so I thought I was in the clear.

    Then came yesterday. I had a full 16 minute flight before the dreaded fall with no problems at all. I did compass calibration before the flight and had full GPS signals and the "safe to fly" message before take off on each flight. There was very little wind and everything seemed fine on both flights until it all went so wrong. On the first flight I was over the water enjoying the sights and landed at the home point when the battery got down to 30% with no problems and no error messages at all during the flight. I was actually starting to fully trust the bird again since I had now had several successful flights since the tumble the day before and there were no signs of any trouble from any of the flight logs. As a matter of fact just before the tumble into the ocean I was thinking to myself thank God the day before was just a fluke because this is so much fun and I still have the whole day ahead of me for flying (I actually bring an external power source with me so I can recharge the batteries while we grab some lunch). Well, I think God answered back not so fast there because right after that came the fall from the sky and I could only watch the screen in horror as the bird kept tumbling down into the water (I could see from the video that it still had power because when one of the arms came into view as it was tumbling the lights under the motors were still on and working).

    One way or another I will get another Phantom. This hobby is just too much fun to abandon it over one horrific day. I will contact DJI on Monday and see if they can figure out what happened and see if they can provide any assistance in getting a replacement bird. Actually, all I really need is just a new bird since I have a controller already, but I don't know if DJI ships just a bird by itself. Anyway, thanks for listening to my long sad story. Hopefully someone here or at DJI will be able to determine what went wrong, but I have a feeling we may never know for sure what happened.
     
  7. HWCM

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    Maybe there was a short on one of the motor wires. It could have happened during the reassembly at DJI?

    Sent from my HTC6535LVW using PhantomPilots mobile app
     
  8. neven

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    It's a **** shame it happened over ocean because this sounds like something covered by warranty. There are some success stories when AC was non recoverable but it will be hard. Or you might get lucky. No reason not to try.

    Sent from my SHIELD Tablet K1 using PhantomPilots mobile app
     
  9. Mocho

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    Would a person expect to get the motor obstructed message if a bird hit your Xcopter? Seems to take a couple seconds of not turning to get that warning, so I'm thinking no.

    One thing I don't see mentioned is a motor bearing failure. Spinning the props by hand will not necessary tell you have a bearing failing due to the magnets inside the motor keeping it steady within the housing. But if a top bearing is failing moving the motor shaft side to side will tell the story. If it moves at all that bearing is failing and the bird should be grounded. I've learned this from experience so I always check my motors on a regular basis. Especially if my P3P sounds different or some happens like you experienced on your first flight with the error.
     
  10. ElGuapo

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    Do you have the flight logs of the day the bird tumbled down to earth but it recovered?. That might help shed some light on what may have led to the fatal final flight.

    See if you were hit by a bird the AC would have recovered from it providing there is enough altitude to stabilize for a safe landing. Like when you had a motor failure the AC started tumble down to earth but since you had enough altitude the AC recovered when the motor started to work.

    Is it even possible to try to recover the bird based on your GPS location ??.


    Sent from my iPhone using PhantomPilots
     
  11. Heisnuts

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    The log from the first time shows the same events just on a different day. I got the motor obstructed message the AC tumbled from the sky but the first time it recovered. When I got it back from the first time I checked everything I could think of. I checked the props - no signs of any impact or even any smear marks like hitting a bird (and i did not see any birds flying around the AC at the time). I checked the motors for temp and ease of movement (I even checked to see if they felt loose in its sockets) - everything felt fine. I then hovered at eye level to check each prop to make sure none of the motors/props had any wobble to them - all were smooth and balanced. I then even ran 2 full test flights over a grassy area with no problems or error messages. All of this leads me to think there was some kind of intermittent failure like a motor seizing up or a circuit board going out. The first time I chalked it up to a bird strike, but I think the chances of 2 bird strikes back to back in different locations is unlikely, especially since I did not see any birds around the craft and I have watched the video frame by frame with no signs of any birds.

    The AC fell into fell into the ocean about 300 to 400 yards off shore in a very rocky area with cold water and lots of strong waves (and it fell way out beyond the waves). I do have my FAA number and even my phone number on the AC, so you never know, someone might find it and give me a call. Now, I do not know if a P3A will float or sink to the bottom, but we actually spent most of the day enjoying the beach anyways and kept a lookout for it washing ashore for about 6 hours. Needless to say, it never washed up when we were there and I think as they say it is sleeping with the fishes right about now. If there is a bright side to that it is with it falling way off shore there was no danger of hitting anyone as it fell or damaging property as it hit the earth. That could have been very bad had it been in a different location.
     
  12. dros1828

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    I had 2 different phantom 2 vision plus that would fall out of the sky and recover themselves, both were bad motors! I was in attitude mode doing a speed run about 50 to 75 feet above the ground and all of a sudden it would tumble like somebody turned the power off and then catch itself.. To find out which motor I just let it idle until I saw one act up or noticeably drop in RPM. I don't see why DJ I wouldn't cover it definitely sounds like there at fault since it happened twice it's just unfortunate that it didn't catch itself and went to the ocean ohh they don't float, at least the p2v+ do not.. Cross my fingers I have had no issues with my P3P.
    --Best of luck


    Sent from my iPhone using PhantomPilots mobile app
     
  13. glord727

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    I can verify that a P3P does not float. I have been swimming around for 3 days trying to find it.

    Mine had 43 flights in the same area and last week after about 12 min of flight, at the low altitude of 20 ft, it spun and tumbled into the lake. It too gave me "Motor Obstructed" notice.

    Have China checking flight log now.
     
  14. dros1828

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    @Heisnuts
    If I were you I would be walking the beach as much as I could it doesn't look like you're too far out, it's more than likely going to wash up..


    Sent from my iPhone using PhantomPilots mobile app
     
  15. Heisnuts

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    Wow, I am sorry for your loss. I would be very curious to hear what DJI says since mine did the same thing yours did just at a much higher altitude. My log says it was falling over 50 MPH as it hit the water, so I can't imagine there is much to salvage. Even if the impact into the water did not cause any damage, sitting in the salt water and being pounded by the waves if it ever did come ashore certainly took away all hope of having anything left that is of any use. Who knows, maybe it will wash ashore in China and DJI will find it and get to the bottom of it (just kidding of course).

    I kinda figured it was going to sink, but since we were planning on staying at the beach all day anyway, I kept looking for it to wash ashore over the next 6 hours with no luck. It looks like after 3,000,000+ feet of flight my P3A had a burial at sea.

    How long ago did you submit your logs to DJI to review?
     
  16. Heisnuts

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    I kept walking up and down the beach for the next 6 hours after the fall with no luck. I actually logged just under 10 miles of walking yesterday. I do have both my FAA number and phone number on the outside shell so if it does happen to wash up I am sure someone will see it since it is a really busy beach. Hopefully if it does come ashore someone will be kind enough to call me and let me know.
     
  17. glord727

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    I contacted N.A. DJI first. Got through that paperwork. Then they forward to China once they verify they have all info needed.

    I think was 2 or 3 days after the Ker-Splash! Mine happened pretty fast from that height, bet that was gut wrenching from altitude you was at. To have to watch it fall all that way.

    I live in a condo on the 3rd floor so everyday I get to look at where it hit the water 600 ft off my patio. I have dived 3 times for it. Only in 10 feet of water. But 5 ft of grass on the bottom and pitch black. Can only see about a foot in front of my mask.

    Going to try one more time with a hand held Gps that shows last know location of aircraft for boat anchor point. Then try using a bright underwater light to see if I can see any reflections from the drone in the deep grass.
     
  18. RocketBrew

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    I have purchased a GetterBack to attach when flying over water, based on recommendations in this forum.

    So far haven't had to fly over water again, but for a few bucks figure it is good insurance to have it on hand when I do.
     
  19. glord727

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    A friend I fly with said they bought me one of those. Have not seen it yet, but so far I have only flew over water since my front yard is a lake.

    But depending on DJI if they say a motor failed or I buy another one, I will never fly over water again without some type of floatation device to keep it from sinking. Never want to go through this again.
     
  20. ElGuapo

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    It is probably at the bottom of the ocean, the battery is too heavy to wash ashore, it is like a brick.

    All you can do at this point is talk to DJI before buying a new bird, they may be able to offer some kind of assistance. I followed a thread about a similar situation and the guy was patient talking to DJI, finally they decided to replace the bird.

    Like you mentioned in your post is that if there is a bright side about this unfortunate event is that you were flying in water.

    I am sorry for your loss.!! It can happen to any of us.