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Lost at Sea :-(

Discussion in 'General Discussion' started by jflyer3, Nov 19, 2014.

  1. jflyer3

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    [Apologize for the long post]

    Sunday was a sad day for me. After dozens of successful long distance flights over the ocean, my last Phantom flight was a one way trip.

    My flight plan was a routine trip to the sea lions who occupy a buoy about 1.3 miles offshore, a flight I did two days prior. As before, I initiated the startup sequence from the bluffs 20 feet above the shoreline.

    The first indication that something was not right was the startup sequence of lights. The P2 immediately started flashing red/yellow instead of green/red. This was a compass error and I had never experienced it before. Very strange. Turned her off and on again. Same thing. I then performed a compass calibration, powered off, then on again. Now the normal green/red sequence appeared. All good I thought. As always I waited until the double rapid fire green lights before take off.

    As many of us know, fussing with you bird tends to draw a crowd. Three teenage boys and three adults were now watching. I took off normally and hovered for a few seconds. I remember thinking to myself that the P2 seemed to be having a hard time maintaining constant altitude and position. Seemed like it made a wide turn instead of a spin when I did a 180 yaw. But maybe it was my imagination. I continued to hover about 30 feet away so the kids could see themselves on the FPV screen.

    When I pointed toward the ocean and headed out, all seemed OK. Maintained 9 meters above my take off height and used the FPV to guide me to the oil rig 1.3 miles offshore. Hovered around for about 1 minute looking for the sea lion buoy but could not find it. Battery was at about 68% so I turned around and headed home.

    The problem happened when I was flying back. I was using the iOSD triangle to hit my home point, but something wasn't right. It seemed like it was coming in slow and drifting in a different direction (but maybe it was my imagination as drifting sometimes happens in ATTI mode). My FPV screen was starting to snow about 1500 meters out, which was unusual because it wasn't snowing as bad when I was further out. Normally I just flip to GPS mode, repoint the helical antenna and the antenna gets the signal back. But not this time. FPV never came back. I estimated I had about 50% battery left so I flicked the failsafe and prayed for a RTH. The people around me were quiet and probably sensed my internal panic. After 30 minutes of waiting I gave up and relinquished my Phantom2 to the ocean gods.

    Here's my take on what may have caused this 'flyaway' but I'm all ears for better explanations. There was definitely something screwy with the compass. The compass error at startup was not normal, and the motion of the P2 on the way home did not seem to make sense. Perhaps my recalibration did not "take" or was not effective. A bad compass would explain why it didn't return home when the F/S was activated. But I still can't understand the sudden loss of FPV video. Wish I had hooked up a DVR.

    One last factoid: After I flicked the F/S I noticed another guy flying his Phantom2 w/Zenmuse/GoPro about 100 feet from me. This was the same model as mine. Could it be that his signal caused my video to go out? I did not see any external antennas on his bird so I don't think he had FPV. (I did a channel scan but nothing came up on my monitor.) I toggled my RC sticks but it did not affect his Phantom. So perhaps there was no interference.

    I know flying FPV over water is inherently risky, but I had done it many times before and have gone much further out. I think this failure could have been prevented if my compass was working properly. Whether I mis-calibrated it or it was faulty is anyone's guess. In any case I contacted DJI and started a dialog. I want to get in the air again. As a good cu$tomer, I am hoping they will help defray the cost of a new P2. C'mon DJI!

    [​IMG]

    I'm not too upset, just kicking myself and wondering what I could have done to save her, if anything. I flew with this fear always in the back of my head. I just didn't think it would happen so soon! Thanks for listening.
     
  2. pilsburypie

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    ****. I had watched your previous flight and really enjoyed it. Thought you were very brave/mad for doing such a long death defying flight, but the footage paid off. One of those things. Crashes/malfunctions do happen, but over water it is game over.

    Good luck with DJI, keep us posted
     
  3. syotr

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    Sorry to hear that you lost it. I enjoyed your previous flight video but was puckered up the whole time.
    I have learned that any time the bird is acting the least bit wonky, to get it on the ground quick. I have had a couple of flyaways that started that way. I was able to recover it and I never really found out what caused the problem for sure. The bird flew fine after repairs and recalibration.
    I love to fly over water so I have built a waterproof, floating quad just for that purpose. That probably would not have helped in your case since you would likely never be able to find it unless it hit the water close to shore.
     
  4. Noël

    Noël Guest

    a sad day indeed, but look at it at the bright side (is that proper English?)
    Time to get an Inspire 1 :)
     
  5. mediaguru

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    Best not to take off if there's any doubt as to the bird's functionality.
     
  6. djczing

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    Sorry you lost your bird.

    I, too, enjoyed your previous oil rig adventure - and my bird is also drawn to water.

    My son has an FC40 that he put aftermarket FPV gear on (2.4GHz), and we certainly did interfere with each other with that setup - with the FC40 in a stock setup, we were fine flying together.

    I have gotten to the point where long distance flying is what I want to do all the time - but I know that sooner or later, if I fly only distance missions that the bird will go down somewhere 'out there' - its only a matter of time.

    If I lost it tomorrow I wouldnt have any regrets. We accept the risk of our missions beforehand, and try to keep risks as small as possible - but Ive had many many successful flights in places where the bird would be close to impossible to recover. These successful flights make me more confident in 'going long', but the longer I go without having a problem, the more likely I am to have something happen.

    I hope you continue flying. The adventure of what we do is worth the risk.
     
  7. kitari

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    Sorry to hear about your loss, I know that's gotta suck. I really liked your videos too. Maybe DJI will work with you to get you back up in the air again soon. Let us know how everything goes.
     
  8. ianwood

    ianwood Taco Wrangler
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    Sorry to hear it.

    If you were flying the heading bug (course to home point diamond) and the compass was having issues, it's likely the conflict between GPS and heading would result in the drifting you described. RTH is an automatic version of flying the heading bug, so it's probable the Phantom was chasing a drifting heading until it lost power.

    The red yellow sequence is an indication that something is so off with the compass reading that it is implausible. The problem exists when the compass can still be way off but not by enough for the FC to detect an implausible condition. The compass is a critical component of GPS flight. Without it, the Phantom has no idea which way to go.

    So in all likelihood, your Phantom's compass was exposed to something distorting its magnetic field. Either it was before the fatal flight and it was enough to leave a residual magnetic charge on the compass. Or there was something magnetic at the take off point and was enough to throw off the compass initialization.
     
  9. max

    max

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    Dang! Sorry for your loss. I was thinking about trying this flight this weekend too..
     
  10. joshuaj84

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    That sucks Jflyer :/ sorry to hear that! I'm here in HB as well and should be receiving my phantom by the end of the week. I've never flown one before except for a tiny little quad but if you have time to show me some of the ropes I'd def appreciate it :)
     
  11. shartlza

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    Truly sorry about the loss!! :( I am sure most of it was compass related. What time did you fly? I am asking this because there was a good off shore flow/wind that started Sunday and was pretty gusty for most of the early morning through about 5-6 PM. If that picture was taken right after your lost it I am guessing it was about 4:30 or so. It was still gusty around that time and even though you may have not felt it much on shore (because the wind was coming in over your head) it would have been much more pronounced over the ocean because the wind would have pushed down over the ocean and be pretty windy. So it could have been a combo of the wind pushing on the P2 and the compass issue making the P2 not knowing the true direction it was going. I wish you the best on trying to get in the air again. Good luck working with DJI on that one!!!

    On another note I did see your videos as well and they always made be squirm. You had some serious cojones flying out that far over the ocean!!!
     
  12. MadMitch88

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    Really sorry to hear about your bird, man --- it now sleeps with the fishes. It had a good life. :cry:

    I enjoyed watching your videos flying out to the oil rig and seeing those cute sea lions sunbathing on the buoy. I'm landlocked in frigid Ohio, so I can never understand how you coastal dudes have a big enough sack to fly so far over deep ocean waters, with essentially no chance of ever getting a bird back when it hits the drink. You got something in your DNA that I surely don't.

    Save up your duckets and buy the Inspire One as a consolation present to yourself for Xmas! :p


    [​IMG]
     
  13. jflyer3

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    Love that graphic, MadMitch!

    Thanks, everyone, for your support. Makes me want to get back into the air again to do more ocean flyovers! ;)

    I agree, Ian. I think something interfered with the compass. I had never seen the flashing red/yellow sequence before and perhaps my recalibration wasn't thorough enough.

    shartlza, you have a good memory! It was very windy in the morning and early afternoon that day (offshore winds, which was unusual). But around 4:30 PM the wind died down significantly and I felt it was safe to fly. But you're right, the wind is usually stronger over the ocean so who knows. The picture in my original post was from a previous flight over the same area on a day when the wind was stronger than last Sunday.

    I agree totally. I weighed the risk and have no regrets. I just wished I lost it on my terms, not because of some glitch. I hope my misadventure and tale of woe does not deter anyone from pushing their quad to the limit! The Phantom platform is very reliable-- just be sure to bring it right back if you notice anything peculiar at start-up or initial hover.

    I talked to DJI and they sent me a detailed 20 question questionnaire to fill out about the incident. Their support team will review and get back to me in 5-7 business days. I filed the report and we'll see what happens. Stay tuned. In the mean time I'll entertain myself by editing some of my last weeks video. :)
     
  14. Meta4

    Meta4 Moderator
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    Another Phantom mystery.
    It's always good to get an understanding of what went wrong to help you prevent it happening again.
    A compass problem may or may not have been a contributing factor.
    Don't get stuck on that idea and ignore other possibilities.
    This one's confusing with lots of possibilities to eliminate before the cause is known.
    When it announced it needed calibration, was it on/near any large steel object or definitely clear of that sort of thing?
    Did you confirm home point lock before flying out?
    What was satellite coverage like during the flight?
    Did you get any info of RTH speed & course?

    I'd guess the compass calibration is either good or bad and that if it "wasn't thorough enough" it just wouldn't be successful and the Phantom would still show a compass error.
     
  15. GerdS

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    Are you sure there was no magnetic influence at the specific location you initialised the Phantom? Many pilots in case of compass error do the mistake and immediately calibrate the compass, although the compass was fine before at another location.
    If there is a locatrion-specific magnetic problem the compass will be fine after recalibration, but as soon as the Phantom is airborne and a bit away the compass calibration will be wrong again.
    Therefore, if you will see a compass error at a new location and the compass was ok before, change the location and try again instead of immediately recalibrate.
    And if you are planning a long-range mission, always check if the compass is working correctly after takeoff, by yawing for 360° at some distance and checking the iOSD display or the directions displayed on phone or tablet for vision(+)(.

    Regards, Gerd
     
  16. ianwood

    ianwood Taco Wrangler
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    There's little mystery. Given the description, it's a pretty safe conclusion that this was caused by bad compass readings.

    General advice would be if you get a red yellow compass warning, do not fly before you check the mod value in a different location. If it's OK, then the spot you were in is suspect. Stay away from it.

    There are apps that read raw values off the magnetometer in your phone. They can help to find and avoid magnetic hotspots. As someone who flies in the urban jungle a lot, I highly recommend it. I've gotten red yellow a few times and used the app to confirm it to be a magnetic hotspot.

    Finally, it's worth repeating that you need to be extra careful about where you calibrate the compass. Do it in an area with its own magnetic field and you'll get a bad calibration that can result in unreliable navigation / flyaway.
     
  17. syotr

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    The thing that is confusing about this incident is that the OP flew from this place before without problems and was able to fly out to the oil rig without any problems. If there was a compass error caused by the location, you would think it would have shown up earlier in the flight.
    In this situation, switching to home lock or course lock probably won't help since apparently both depend on the compass. Turning off the transmitter to initiate RTH won't work either for the same reason. With the bird out of visual range, manual flying isn't an option. The only hope might be flying by FPV if it was working.
     
  18. ianwood

    ianwood Taco Wrangler
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    Either it was a slightly different take off point which happened to have a lot of hard/soft iron magnetic "noise" in the immediate area or something magnetized the compass between the two trips. Or the compass was failing.

    The only option in this case is to switch to ATTI and use the FPV for "dead reckoning". You can still use the OSD horizontal distance to see if you're getting closer or further away as that shouldn't rely on the compass. Go forward and start a slow shallow turn until the horizontal speed matches the decay in horizontal distance. Consider cross winds if you can get that far.
     
  19. syotr

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    If I understood correctly, he had lost FPV signal so OSD data would not be displayed. The only hope would be to continue flying blindly in the direction you were heading, hoping the signal would return.
     
  20. BlackTracer

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    Sorry for your loss. Has to be heartbreaking. One thing I ALWAYS do is verify my home point before leaving on my main mission. Many others do this too. After lifting off, I fly on an angle away and up about 50-100 feet distance and 20-30 feet height. I then flip S2 to HL, pull the right stick back and see if it returns to home. If it does, off I go! It has never not come straight home, but if it didn't I would guide it home and start over. Just wondering did you do this or similar?