Uncommanded Roll! - Advice.....

Discussion in 'ALTA 8' started by Jay P. knight, Jul 25, 2016.

  1. Jay P. knight

    Jay P. knight New Member

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    Hello,

    I had an uncommanded roll today and it was scary. It happened on another flight and I thought maybe it was my input, but when the same type of thing happened today, I nearly had a heart attack. I was able to quickly correct the flight, but when I am low to the ground, there is not much time.

    I have the files, but they are challenging to figure out. Does anyone have any insight or a simulator that will demo the flight on the Flight Data files. Both flights had 5d with Movi15 underslung and top mounted with 2x16mah. I had no warnings before and after each flight, and the rest of the flights went very well.

    The flight data files are too large for me to upload.

    Any advice would be greatly appreciated.

    Thanks
     
    #1 Jay P. knight, Jul 25, 2016
    Last edited: Jul 26, 2016
  2. Gary Haynes

    Gary Haynes Administrator
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    Jason post your flight logs.
     
  3. Jay P. knight

    Jay P. knight New Member

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  4. Dylan Glockler

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    Are you on the latest Firmware? If not, which version?
     
  5. Jay P. knight

    Jay P. knight New Member

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  6. Dave Thomas

    Dave Thomas New Member

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    There was a temporary GPS loss of signal while giving a full stick input with the velocity clamp set to minimum. The jpg attached shows the key points. It was the abrupt switch between Position Mode and Manual Mode that made the roll appear to be unexpected.
    • 204 sec: pilot input full roll left command while in position mode with velocity clamp at minimum. Therefore, the ALTA would have started rolling left at a very slow velocity.
    • 213 sec: momentary GPS LOS occurred, so the ALTA automatically reverted to Manual Mode. The pilot still had full command roll left, and the ALTA instantaneously banked hard left
    • 213.5 sec: GPS signal was regained, so the ALTA switches back into Position Mode, making the abrupt roll appear to have been uncommanded
     

    Attached Files:

  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Ouch. Scary indeed. I would be in the market for new underwear.

    I suspect that there's a loose cable in there somewhere. I would contact FF right away -- there's nothing that I know of (short of a dodgy electrical connection or other electronic fault that should cause a glitch like that....(support@freeflysystems.com).

    Andy

    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limitâ„¢
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     
  8. Jay P. knight

    Jay P. knight New Member

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    Hi Andy and Dave,
    Thanks for your response.

    Here is what I received back from Support a while back from Adam:
    Adam has been great, always a quick response.

    Andy, If you think I should send it back to Freefly, let me know. I would hate there to be electrical problems on a shoot while I
    am flying.

    Adam Henley (Freefly Systems)

    Jul 27, 8:59 AM PDT

    Hi Jason,

    Thanks for your patience while we evaluated your log files.

    It looks like what caused the abrupt instability was a very short lived GPS signal loss. Since you were flying in Position mode and the rate clamp was down, this caused the aircraft to fly very docile while it had GPS. When the GPS experienced a very brief loss of signal this cause the ALTA to switch to manual flight for just a moment. Since you didn't switch to manual mode intentionally it felt like a glitch.

    We have a data viewer available for download here if you would like to check it out: https://freeflysystems.zendesk.com/...-software-available-to-view-ALTA-flight-data-

    If we can be of further assistance please let us know.

    Best Regards,

    Adam
     
  9. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    That seems a very credible explanation, Jason.

    As Adam suggests you might want to download that log viewer software so that you can monitor any future flights if you see a brief glitch again.

    You might also want to just snug down the antenna on the GPS unit -- I don't mean to really crank on it -- just make sure it's snugly tightened down just on the very slight off-chance that the antenna is loosely mounted. Don't over do it! :)

    By the way, if it's not too much trouble, would you be kind enough to change your user name to your real first name and last name, please? The reasons for this (and how to do it) are explained here: http://forum.freeflysystems.com/index.php?threads/real-names.497/

    Thanks
    Andy
     

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