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My first near flyaway --> CSV Analysis added with intereresting discoveries!

Discussion in 'Pro/Adv Discussion' started by Foosy, Jul 28, 2015.

  1. Foosy

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    Flew my P3P yesterday. All was good for multiple flights, until one flight when things went bad:
    Compass MOD was OK, around 1480. I took off in front of a church at night, and was going straight up.
    Then, when it was high up, it suddenly started drifting without me moving the sticks. The app showed a red alert "compass error". I tried to get it back but it was going further away, missing a building and at that point I really got scared as there were people in the area and I did not have control over it.

    I had just planned going up and down and was not ready for the elevated heartbeats, especially as a person next to me shouted: " if that thing scratches my car, I'm going to kill you..."

    The p3p was still high up, and seconds looked as minutes. I think I switched it to Attitude mode, and after getting my orientation, I was able to get it back and land it without hitting anything. It felt like navigating a boat in a huge storm. When I regained the phantom, I looked at the controller and it was in Attitude mode and I was wondering- did I send it like that, or did I switch it in midair when the problem occurred? I will need to check the logs to see what exactly happened, was it instinct, user error or a p3p issue.

    Now is the time I wish there was a sticky post with direction how to pull the logs and analyze them....

    [UPDATE 7/29/2015]
    II got the following information from the log file:
    1. There is no compass error - even though the app alerted me there was....
    2. The bird switches to using VISION at the time 00:29.5 until 01:02.5 ?!?!?!!!
    3. For the same period as above the unit gets a YAW_ERROR_LARGE for nonGPScause
    4. Throughout the flight, imuInitFailReason is set to MonitorError, but imuInitFailReason.raw is 0, so does not seem like a problem
     
    #1 Foosy, Jul 28, 2015
    Last edited: Jul 29, 2015
    Mike Mauk likes this.
  2. PhantomFilters

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    Sounds like a scary experience.

    If the switch was in ATTI-mode you must have done it physically? ;)

    To me this is a reminder to learn to fly the Phantom without all the aids all the time - meaning learning to fly in ATTI-mode without the GPS-assistance. It is vital to know how it reacts when something like the GPS fails.

    Only way to prepare is to take off the GPS-training wheels once in a while - even when there is a bit of wind - and getting a good feeling of how it handles.
     
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  3. Foosy

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    Yes, i have absolutely switched it. i just need to check if it was done before the flight, or when the problem started. In the heat of the moment, making decisions, I acted instinctively. Now that I am relaxed I will do the analysis.

    As to knowing how to fly it in attitude mode, I agree and I have done it. This is why I was able to recover it. But it is still always scary when it happens...
     
  4. Foosy

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    Making some progress/
    I was able to get the p3p in "flight data mode", and am able to see the files.
    I am now copying them to my computer, BUT the dates of the files do not make sense to me:
    The newest and last file is from today, and I did not fly it today.... Interestingly, it is a very large file and its timestamp is the time I connected the p3p to the computer
    There are 2 DAT files from yesterday, but yesterday I had 5 flights.

    Boy, this is slow copying!
    I need to figure this out....
     
  5. PhantomFilters

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    Yep, and with anything worth doing, it is worth training and training in order for it to become second nature and not be a harrowing experience when something out of the ordinary happens.

    No doubt flying the Phantom and have something happen can get the blood flowing. It can certainly be stressful. Even though it is not a big machine it is still a big responsibility to fly these things, especially around people. On the other hand, doing something that pushes you forward - including the stress of flying around other people, is valuable training as well.

    Wish I could add more to what happened. I've had the "Compas error" pop up once in a while too and that was stressful - but I don't recall noticing any change in flight behavior. Maybe because I was flying around with the Phantom in a way where small deviations would not have been noticeable.
     
  6. Ferdi

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    Easiest way I believe is to just use the Flight Records in the Pilot App to see when you switched to Atti.
     
  7. PhantomFilters

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    Why not jus review your flight in the Pilot App (User Center -> Flight Record (logbook) ? You can go thru the flight there - and see when you were in P-GPS and when you were in ATTI mode.
     
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  8. PhantomFilters

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    Great minds think alike ;)
     
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  9. Ferdi

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    Location:
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    :D
     
  10. Foosy

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    Yes, that is a good idea. I have done neither before, and its definitely time I learn how to do this. But I also want to check the "full data logs".
    In any case, couldn't they have made the interface faster? 710KB/sec copying is abysmal... 32 more minutes to go....
     
  11. BigKenny

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    Edit: Never mind...read this wrong!
     
  12. Foosy

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    Looked at the flight record, and I see the following:
    00:00 Start with P-GPS
    00:05 Takeoff to a vertical climb
    00:37 the mode change from P-GPS to P-OPTI, at a height of 33 m (100 ft)
    00:55 it starts drifting
    01:18 A warning message shows up: Warning: cannot switch current flight mode. To switch to A/F mode enable Multiple Flight Mode in Settings menu.
    01:19 Switches to Atti mode
    01:19+ Switches to P-GPS mode
    01:56 Lands
    02:00 CSC, still shows P-GPS

    Image shows the moment it switches to P-OPTI, no stick-inputs were given.
    Open to interpretations
    IMG_1660.JPG
     
    #12 Foosy, Jul 29, 2015
    Last edited: Jul 29, 2015
  13. Ferdi

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    Since you didn't have "Multiple Flight Mode" on in the app you never actually went into Atti mode, even though you flicked the switch. You most likely had a bad compass calibration. Happens often with the Inspire1. Good job bringing it back while your compass and GPS was fighting each other!
     
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  14. Justgregg

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    If the p3 loses gps dosnt it automatically go into atti mode, then when it regains gps it switches back? I think my inspire did that on one of my flights. Windy day and when it switched to atti it felt like a fly away, but it wasnt. Just the wind making it a hand full to fly in atti mode.
     
  15. Ferdi

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    Yes you're right that the P3 switched to Atti if it loses GPS, although it seems to have done so only briefly (for about a second when he got the Compass error message). Getting the compass error message seems to indicate a bad calibration.
     
  16. Foosy

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    This is interesting, although I must admit, I am still not grasping what exactly happened.
    By the way, I did upload the DAT file to http://www.djilogs.com/, and it created a log file which has a bunch of commands that I do not know yet how to interpret. Any pointers or should I use a different program?
     
  17. Foosy

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    Had flown it 4 other times that day in same area and I always check the MOD value. All were OK. Interestingly, it got the Compass warning while it was 100ft high in the air. Why would it go wrong then?


    Also, worth noting, the whole path of the flight and home point are off by about 30 to 40 ft. I would not expect such a high discrepancy from GPS.
     
  18. PhantomFilters

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    I can't say for sure - but it is fairly easy to hit that little switch on the left by mistake.
     
  19. Justgregg

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    Now is it true that the inspire and the phantom 3 do not need compass calibration all the time. I was flying another airframe with naza v2 and dji was wanting you to re callibrate if you travelled over like 100 miles. I travel up to 30 miles between photo shoots as I film farm properties, should I be re calibrating after re locating?
     
  20. PhantomFilters

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    I think 30 miles is on the short side for a real *need* to recalibrate the compass. But honestly, I'm not sure. It can't hurt to calibrate the compass if in doubt.