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Flyaway problems

Discussion in 'Phantom 2 Discussion' started by Mike, Jul 6, 2014.

  1. Mike

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    I've had my P2 for a few months now and experienced erratic behavior for the first time the other day. Calibrated and all greens with 9 satellites. Took off in GPS mode and got about 30m up and it suddenly took off like a rocket to the right. I had never seen it roll that far in any direction. I slammed the stick to the left with no change at all to the flight direction. I flipped the switch to FS but got zero response. My heart was pounding now as I'm watching it tear off over open water. I flipped the switch to ATT and finally was able to regain control. It was essentially responding like it was in manual mode at this point. I was able to bring it back and land it. I did a recalibration, powered off and on and recalibrated again followed by another power cycle. I relaunched and hovered about 15 feet up for a little while slowly moving it back and forth in different directions. Everything seemed fine again. I took it up a little higher and headed out slowly, shooting straight down. About 3 minutes later I centered the right stick but it kept heading off in the direction it was previously flying. I flipped into ATT mode and regained control. At this point I noticed that my GPS was bouncing back and forth between 12 and 0 satellites. I landed it and took it back to investigate. Assistant software said GPS needed to be recalibrated. I did and everything looked good in the software. I took it apart and checked the connections. Everything seemed fine. Took it back out and it was flashing red/yellow. I did calibration, got green. Powered it off and on and it was back to red/yellow again. It took 3 more tries before it stayed green on power up. Took it up and flew 2 batteries with zero issues. Went back out a few hours later, calibrated, took it up and it immediately took off with a mind of it's own. Can anyone shed any light on what is causing this behavior?
     
  2. jerrymac12000

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    Location:
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    Where are you located?
     
  3. Mike

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    I was in Chicago at the time at a park on the lakefront. So far I've flown in Atlanta, Dallas, Savannah and Orlando without issue.
     
  4. jerrymac12000

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    Around the 1st of July, in one of the forums, someone had posted a message from the FAA saying some GPS testing and interference would be taking place. Colorado and several other states were listed. The interference testing would continue until the end of July. Just be careful.
     
  5. Mike

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    Scary!
     
  6. tbwester

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    Also, solar winds have a very real effect on GPS signal strength. Although, if you can connect to 12, then it shouldn't bounce back and forth.
     
  7. oldphantompilot

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    First flight, last flight.

    5 July

    This sad tale is regarding my brand new Phantom 2 Vision Plus. I am not a DJI rookie, having made dozens of successful flights with my Phantom 2 Vision. But my message to myself and maybe some readers is this…we are all rookies just as soon as we get behind the curve, and/or in over our heads. So,


    Saturday I went into beautiful northern Idaho, in a large clearing in a pine forest. Clearing perhaps 100-150 yards wide, surrounded by tall (50-80 foot trees) and also a few smaller scrub trees. Fairly wide open to the west and the east. I made two flights.

    First Flight.

    Naza mode, both switches up.
    Cal the compass. Success.
    Wait for GPS lock, probably not long enough. Could not adequately tell if I had success, but looked like I did. Could not really tell looking at iPhone either. Brilliant sunshine. Too much screen reflection. Took off. Maybe up 25 feet, copter went fine, then became weird. Veered off fast and into scrub trees. Phew, I found it, props still spinning. Maybe two minutes all together. All was well, save for some green smudges on the arms. Camera fine.

    Second Flight

    Immediately after a cursory inspection of copter, all OK, prop leading edges smooth. Camera gimbal fine.
    Naza mode. Both S switches up. I checked.
    Compass Cal again.
    Same battery. I have three, why I didn’t just go to a fresh one is beyond me. But I didn’t. Too much wanting to please the onlookers perhaps? Getting into even more of a hurry? Too sure of my flying skills?
    Same GPS questions as first flight. But I still took off again.
    Up 30 feet, all good. Flew at about 30 feet over the tops of the tents and camping rigs, pointed camera down. Video running always. Fine for several minutes. But certainly no immediate problems as with first flight.
    Now once again, the craft went screwy is my best description. Sashaying back and forth.
    Now my details get fuzzy. I was instantly into panic mode. I became a complete rookie again!
    I “escaped up”, due to the big trees. Maybe 150 or 200 feet.
    Tried to see copter orientation, could not be sure. Phantom beginning to fly away to the north. Left switch down, home lock attempted. Why I didn’t put S1 down for RTH, I don’t know, but I didn’t. S2 down. No luck. Off she went. Behind the big trees and out of visual.
    All of this last panic to the tune of my low battery warning. A real multi media thrill. I suppose the panic and loss lasted less than a minute. It happened fast.

    Looking back, some observations…
    I will now consider my take off point as if I am in a big water glass, looking skyward. The trees or buildings form the sides of the glass. I will make certain I have lateral room, not just upward. It was too easy for me to get too close to edges of the glass. Thus I was in a GPS hole when I took off, and was in a hurry as well. I think I had spotty, iffy GPS lock at best. Maybe 5 or 6 or 7 sats, no more, and off and on at that. I didn’t wait for things to become more ideal. Because I had never crashed before, therefore I never would. Wrong that!

    My iPhone screen was way too reflective, and not really of any use. Before I was always in wide open areas and flew with line of sight easily. Those line of sight skills on Saturday were of no use when I got behind those trees.

    I left on my last trip with a partial battery. No idea why I didn’t change it out. What ever time I may have had to save myself was cut way short.

    I followed my iPhone to last position, but no luck. I suppose that last position was when the battery died, 250 feet up and maybe going 20mph. The jungle in a pine forest is way worse than in deciduous trees. It is knee and chest deep scrub vegetation under tall pines with dense needles. My Phantom is still there, someplace. I looked.

    To top off my mistakes, afterwards I looked at my settings. I had turned on Ground Station, just to play around with waypoints a few days before this fly away. I have no idea if it made a difference on Saturday, but I cannot think it helped that I left that turned on.

    I hope others can chime in about my bad decisions and actions. My final thought is that thinking I could handle anything was foolish, and that not following my own little mental checklist cost me my bird. Pro pilots never depend on memory or just thinking all will be OK. We should not either.

    Thanks for any comments.
     
  8. q8f1

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    Bummer, hope you find it, thx for posting.
     
  9. sergekouper

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    Nice of you for not blaming DJI or your equipment, and thanks for this reminder to not be over confident and this advice of not relying only on memory.
    I had this situation once of the phantom not fully locked at take off, in a quite closed place (a very little harbour surrended by cliffs) I didn't feel like risking it, I backed off, a bit ashamed with myself but reading your story, I made the right choice!.
    Thank you for posting.
     
  10. ianwood

    ianwood Taco Wrangler
    Staff Member

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    Let's dismiss some of the suggestions. It is extremely unlikely the GPS interference testing being conducted in NM has anything to do with this. Solar winds the same. Mike's issue sounds like a problem with the GPS hardware. That it results in a true fly away is scary but it could be the GPS unit is sending bogus data to the Naza. I do remember there was a similar case a while back but for the life of me couldn't find it from all the other less verifiable or claims.

    oldphantompilot, it is hard to interpret your case as there aren't enough hard details and a lot of variables. The number of satellites locked in will strongly influence the behavior of the Phantom. Less than 7 satellites and your Phantom will start to act like it is in ATTI mode.
     
  11. SJBrit

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    If your GPS is coming and going like that then it's suggestive of an antenna connection issue - I would check your wires, including under the antenna cover. Also, you might want to check the antenna for cracks - that would tend to degrade performance rather than make it intermittent, but it's worth a look while you are under there.
     
  12. Mike

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    I didn't check the connection to the GPS unit itself. I only checked the connection to the board below. I will open it up and check today. Thanks for the suggestion.
     
  13. Mike

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    Ok, I removed and inspected the GPS unit. Everything seems to be fine - no cracks. I did notice a small battery on the board. What purpose does that serve?
     
  14. scratch009

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    Had a similar problem few weeks back. Took off with 7 satellites, while I was up flying suddenly my FPV screen showed me 0 satellites blinking. Clear sky and checked a website afterwards saying there was actually low solar activity. location, Belgium.
    Scary that GPS loses signal that suddenly
     
  15. ianwood

    ianwood Taco Wrangler
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    The battery allows ephemeris and almanac data to held between power cycles. It basically supports a warm boot which means that it will take a lot less time to acquire satellites if you recently used it in nearby.

    (And just to repeat it, if your GPS shows 0 satellites, it isn't "solar activity" or any other celestial event. If it were, having 0 satellites will be the least of your problems!)
     
  16. Mike

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    Thank you. Hopefully I'll have a chance today or tomorrow to take it out for some test flights.
     
  17. Mike

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    I took it out today and ran 3 batteries through it with no issues. I just hope that was an isolated incident in that location that caused the complete GPS signal loss. It's a horrible feeling to watch it take off in a random direction at full speed.