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Inspire 1 Crash: Power loss in mid air

Discussion in 'Inspire 1 Help' started by xaven, May 8, 2016.

  1. xaven

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    Hi Board!

    Yesterday I was shooting stills and movies of a bridge. I was flying under the bridge. It was clear, that I will lose GPS and keep flying in ATTI-Mode, when i´m under the bridge. Here is what happened:

    02:46 Weak GPS Siginal
    02:47 Weak GPS Siginal
    02:48 No GPS Siginal
    02:51 GPS OK
    02:57 No GPS Siginal
    02:57 Disconnected

    At the moment the Inspire disconnected the video ends.
    A second later my colleague and i saw, the Inspire falling from the sky into the river beneath. Ist was leveled out - no rotation or something else. Seemed like it had a complete Power loss. We were unable to recover the debries until now. Battery was fully charged when we takeoff. There were no warnings, Battery was at the time of the crash all green with 72%.

    Firmware of the X5, Inspire and Remote were all latest version.
    Go App was Version 2.7.2
    The Flight Recorder data also got no anomalys. Everything fine.

    How can such a thing happen?
    The Video from the Cache is here:
     
  2. DavidB

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    Is it possible your RC lost contact with the Inspire and the Inspire started to climb to the return to home altitude, crashing into the bottom of the bridge. Looking carefully at the end of the video seems to show the craft climbing. Sorry for your loss. I await further comments with interest.
     
    ringolong and Dr. Ifly Drones like this.
  3. xaven

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    Hi David,
    that was also my very first thought the inspire was final in 54 M AGL and the bridge is on top about 57 M. The Flight Record is showing me the final point under the bridge, but when i import the Flight Recorder Data in Google Earth Pro you can see that it is not.

    Coming home altitude was set to 50 M AGL.
     

    Attached Files:

  4. DodgeP

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    Where is your/rc position while filming? Terrible loss. 3 meters is not that big of a difference and it's a distance small enough that could leave room for error in reporting. Especially when you note that the RTH radius is about 3 meters.
     
  5. Ozziepauly

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    Would flying under a four lane bridge at slow speed be any factor? Sorry for your loss.
     
  6. DodgeP

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    Of course it does that's why I asked where his position was.
     
  7. DavidB

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    Xaven

    You have indicated a 3m difference between the Inspire and the bridge. That's very close flying. I note there are 2 bridges with the second lower than the first. Was the 57m taken from the top of the bridge which would have the bottom surface a few meters lower again? If the video you put up was all that the iPad/Android recorded, I would still suspect a loss of signal as critical. I've seen many an Inspire (or Phantom) transmit video as the aircraft plummets after impact. My guess is you lost signal with the Inspire so close to the under surface of the bridge, contact quickly followed and the Inspire fell into the river.
     
  8. Scotflieger

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    You will get much better information to analysis your flight using the free HealthyDrones website. Just import the flight record and share the flight to forum members.
     
  9. OuterLimits

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    Not sure if this is the correct way to jump in...but my Inspire 1 fell from 400' with a complete power loss...I wasn't present but the description given to me was that it was flying perfectly over a field and then just plummeted to the ground.

    The repair from DJI said "User error sitting off motors while in flight".....obviously didn't read the manuals well enough to know that could be done....is the only answer to that the "CSC" description I saw in a previous thread?

    Hard Lesson Learner.......
     
  10. The Editor

    The Editor Moderator
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    Yes - whoever was flying it at the time was inexperienced and executed a CSC command and that will shut the motors off instantly.
     
    SteadiMikeG likes this.
  11. n9ami

    n9ami Guest

    Sorry bout that but I am glad most of you people aren't flying full scale airplanes there is not a lot of common sense going around these days needless to say skill. Just seeing to many accidents as of late.
     
    Brandon Rowe likes this.
  12. Brandon Rowe

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    Can we keep those posts under one thread. At this point I don't think we need to see a new one every week. Also, if you are pretty sure you are going to lose GPS, maybe switch to ATTI on your own.
     
  13. Ralph thompson

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    There Are a few assumptions above.
    1. Was all the routine maintenance done, ie batteries. No more than 20 cycles followed by full discharge & recharge. If the cells get imbalanced, the smarts can get fooled.
    2. Basic & extended UAV structure checks, ie no cracks especially around props, all connections secure, etc
    3. No problems on the pre flight & launch checklist, ie all screws secure, propellers locked, all signals normal on immediate takeoff, no weird noises, etc
    4. Are u aware of the fresnel effect on LOS radio transmissions, ie u maybe able to see the UAV clearly with yr eyes but if u get close to an obstacle, especially one that is conductive, large metal objects, then u can get distorted radio signal LOS & then interference.
    5. Knowing u were flying under a low ceiling, was the RTH altitude set to lower than the bridge recognizing that things never go wrong at the right time.

    Just a few thoughts but procedures are really important for a sophisticated & expensive piece of equipment like the Inspire 1
     
    Wolnski likes this.
  14. Wolnski

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    I fly on construction jobsites every week. A tower crane will cause major interference with your signal. You have two tower cranes in your video. It is particularly a problem whenever the cranes are located between you (and your remote control) and the drone. The signal will be lost. What height did you have specified in your settings for return to home? If it was higher than the bridge and it lost signal while it was under the bridge then it could have crashed into the underside of the bridge while attempting to return to home.
     
  15. SteveDrone

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    Il you did experience a signal lose while having a weak gps signal, your drone could have just drift and land in the water.
     
  16. Ralph thompson

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    Good point Steve, although I find the number of GPS's fluctuating all the time but in the open air, it seems to be in the teens. I'm guessing it picks up GPS & GLONASS? I rarely get down to 6 or whatever the minimum number is unless I go indoors
     
  17. BudWalker

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    If you could retrieve the .DAT file from the Inspire there is a lot we could learn about the cause.The .DAT file is on the A/C not the tablet and contains a lot more info than the .txt coming from the tablet. E.g.,if the A/C hit the bridge that would be evident in the accelerometer data. I developed DatCon an offline .DAT converter that can be obtained by going here. Instructions on retrieving the .DAT can be found here. If you can provide a Dropbox link to the .DAT I could take a look at it
     
    Elvin Ho likes this.
  18. WILLIAM BAKER

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    There is not as much as you are thinking. There are thousands of people flying and maybe over a million so your not even seeing 1Tenth of a % of people having accidents. Just saying!
     
  19. IrishSights

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    It would be a nightmare as it would be ambiguous which incident was being responded to.
     
  20. Bryan Conover

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    And conveniently the video is no longer viewable....usually happens at the request of DJI to keep things quiet.