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Flyaway Question

Discussion in 'Phantom 2 Vision + Discussion' started by murraymacdonald, Aug 25, 2014.

  1. murraymacdonald

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    Hi all,

    I just had my Phantom 2 Vision Plus fly away on me. It's been over 40 minutes so it's no longer in the air. I made sure I had a good GPS lock before I took off, had 7 satellites, and the compass had just been calibrated. It indicated "Ready to Fly" by slow blinking green, but a spent a few minutes adjusting the camera parameters before taking off. It slowly blinked green with 7 satellites. The flight seemed fine for the first few minutes. After 3 minutes of flight the FPV video got crappy. After 30 seconds with no FPV and no visual I turned off the controller to activate fail safe mode. It never returned. My questions are:

    1) What does the phantom 2 vision plus do when it can't get 6 GPS satellites to lock by? What happens when it has 5 ? If it doesn't have six, what EXACTLY will fail safe do?
    2) How does it know what altitude the ground is?
    3) What altitude does fail-safe "land" at if I take off on the side of a hill?
    • A) the altitude it took off at?
      B) the altitude of the ground at the location it's at?
      C) or ...
    4) When the battery is runs out does it lower itself x feet per second, or just shut off in mid-air and fall like a rock?

    Any insights would be appreciated. I'd like to better understand my $1000+ problem.
     
  2. Mako79

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    Location:
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    1. When it drops too many satellites, it switches to ATTI mode. ATTI mode doesnt support GPS therefore it hover and then autolands. During this hover period, it will drift in the wind.
    2. Altimeter in the IMU tells the barometric reading. It then zeros the altitude on takeoff.
    3. Answer is C. It doesnt care what height. It just descends until it cannot descend no more. Once it feels that the altitude is no longer changing for more than 3-5 secs, it kills the motors.
    4. Autoland. It will only shut off if you are at 0% or if you have executed CSC.
     
  3. Panamon Creel

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    To 1.) don't have the answer on that one, theoretically it could still return to Home with less than 6 but more than 3 sats, it would just be less accurate but don't know if the Naza-M will still RTH with 3-6 sats.
    To 2.) it uses a barometric sensor
    To 3.) B is the most appropriate answer, it descends slowly and stops where the ground is at :)
    To 4.) it should autoland if the Battery goes to critical level

    P.S. RTH will be at home location alt +20 meters if connection was lost flying at below the +20 meters altitude and at current flying altitude if above the home +20 meters. Anything in the RTH path higher than that will provide a sudden stop for your phantom ;)
     
  4. murraymacdonald

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    So if I understand you correctly, it likely set itself down gracefully, even though the ground was 300-400 feet lower than the launch point. I suggest everyone write their phone number on their drone in sharpie. Sure wishing I had...
     
  5. AHill

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    1) What does the phantom 2 vision plus do when it can't get 6 GPS satellites to lock by? Does it need all six to fly home? If it doesn't have six, what will it do?
    Needs 6 to fly home, will land straight down without 6 but it may keep drifting with the wind if less than 6 satellites until low battery if it didn't get fail safe command, then land.

    2) How does it know what altitude the ground is? Barometer built in, relative to take off point altitude.

    3) What altitude does fail-safe "land" at if I take off on the side of a hill?
    B) the altitude of the ground at the home point location, it will sense not going down when it lands and shut off. It keeps slowly going down until it senses that it has landed. When coming home with fail safe it will return at about 60 ft. above home point altitude then land straight down unless it was higher when failsafe is triggered, then it will remain at that altitude until it gets to home point, then land straight down.

    4) When the battery is runs out does it lower itself x feet per second, or just shut off in mid-air and fall like a rock? It should land straight down at low battery warning if less than 6 satellites.
     
  6. Fplvert

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    Did you try find my phantom on the app? It should give you an idea where the bird was the last time it had at least six sats.
     
  7. Jstic

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    Don't count on it setting itself down gracefully when in ATTI mode and failsafe landing engages. Unless it is a day with absolutely ZERO wind, the bird is going to start going sideways in ATTI mode, and it will try to land going sideways. Ask me how I know. It will slow down in speed, but if and when you find it, I doubt it's going to be upright.
     
  8. jodaddy23

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    sorry for your loss , i try to never lose sight of mine .
     
  9. tmc6663

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    I had a flyaway on August 12th, I think due to pilot error. I went out on a long range flight without enough battery power to return. Fortunately I had wriiten my number on the quad and it was returned yesterday, August 24th. It cost me a $50 finders fee, a small payout, considering how much I'd had invested in the bird. It was the longest 12 days I have had in recent memory. I now am in need of the best tracker I can find before I'll feel comfortable going out in another long range flight. I highly recommend putting your phone number on the quad somewhere to increase the chance of it being returned. I am even thinking about engraving it on there, so that it cannot be removed at all.

    I too am sorry to hear about your loss...no possibilities of finding it?
     
  10. murraymacdonald

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    The Find My Phantom feature of the app is showing me where I flew it last week (over 300 miles away). How can that be given that I had 7 satellites for minutes for 3 minutes of flying and had slow flashing green for many minutes before taking off? Would it really try to fly 300 miles home? I was in GPS mode; both switches up. What exactly would fail safe do if the home location is 300 miles away and why wouldn't it lock onto the take-off location with 7 satellites? If it did try to fly 300 miles home, how far would it fly with 90% battery and no wind? Assuming 90% of a 25 minute battery at 35 MPH that's 11.5 Miles or 18.5 km which would take it over an international airport. What would the flight controller do in fail safe mode when flying home involves flying over an airport? Also, what happens when the battery gets exhausted? Does it keep trying to fly 290+ miles or does it set itself down at some point?
     
  11. murraymacdonald

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    The Find My Phantom feature of the app is showing me where I flew it last week (over 300 miles away). How can that be given that I had 7 satellites for minutes of flying and had slow green flashing for many minutes before taking off? Would it really try to fly 300 miles home?
     
  12. Fplvert

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    So you didn't do a compass calibration at the new site? Maybe you never got home lock?
     
  13. Michigan_PI

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    I would not consider this a "Flyaway"
    It sounds to me like your home point was not set properly for one reason or another
    You lost sight of it, initiated RTH and it tried to do just that.

    I also suspect that failure to set the home point is the cause of many of the reported fly-aways.
    There are another issues that poor GPS reception can give. I used to have a GPS receiver (old DeLorme) that would report it was off the coast of Africa when reception was crappy and it was still "warming-up"
    Now if a Phantom has a poor GPS signal and thinks it is someplace that it isn't, bye-bye birdie
     
  14. cahutch

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    2.) It doesn't know where the ground is, until it touches the ground.
    Home point can be reset and it can land someplace other than where it took off from.
    The altimeter changes tell the phantom that it's descending. When it's reducing throttle and still descending it hasn't touched ground yet.
    When the altimeter reading hasn't changed for three seconds, despite continuing to reduce throttle, it decides it must be on the ground.
     
  15. murraymacdonald

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    By calling DJI support I got answers to few of my questions. I thought I'd share them here.

    1) Yes it will try to fly home 300 miles.
    2) When the battery gets exhausted it will try to land regardless of where it is.
    3) If it comes within 5 miles of an airport while flying home it will immediately land.

    I've concluded that it crashed into Stanley Park which is heavy dense forest. After three hours of searching on foot I've realized it's never going to be recovered.

    Lessons:
    1) NEVER fly until home lock is confirmed. Shut down the device and check that "Find my Phantom" correctly locates it before flying anywhere. The app is deficient and should give you a warning before you fly if your home lock location is more than a mile away from where you are taking off. It's a design oversight that cost me a my Phantom 2. Fail Safe has the potential to send your drone off onto the horizon never to be seen again.
    2) WRITE your contact info on your drone.
    3) ADD a lightweight bluetooth beacon that will transmit for months on a watch battery to help you locate it if it gets lost in the wilderness. Knowing you were within a couple hundred yards would make all the difference.
    4) Don't trust failsafe mode. Always try IOC home lock mode and go backwards before trusting Fail Safe.
     
  16. Michigan_PI

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    You can look on the lower left of the app and see if your home lock is registered to your current location. At least on an iPhone you can.
    A small GPS locator would work better than a bluetooth or perhaps in conjunction with a bluetooth although mine is generally spot on.
    I have the TAGG on the belly behind the camera:
    viewtopic.php?f=4&t=15262&p=144721#p144721
     
  17. juangelb

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    Hi murraymacdonald,
    I really sorry for you very bad experience... But
    1- INHO i think that the home lock is a good practice to have before evry takeoff. I always clisk on the left lower side of app and check if walking around PV2+ 360ยบ .. ir shows me the whole around walking, confirming that she knows at sure where it is.
    2- IOC home lock ... it the bird did not register the home point ... will be useless... in your case backwards could be 300 miles away ... as home lock is based on home point.

    Best regards : Juan
     
  18. Zinnware

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    Another note about confirming the recording of the home point... I have seen posts and videos where operators believe that the confirmation is reflected by rapidly flashing green lights on the Phantom. (I have a Phantom 2 (non_vision)). If in NAZA-M mode, you must wait for two sets of rapidly flashing green lights. One set is for the Course lock, and another for the Home Point location. I set my min Satellite setting to 7. It appears that it will still lock on the home point with 6 satellites, but the rear lights will not slowly flash ALL green until 7 are obtained.
     
  19. murraymacdonald

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    The question is why doesn't it home lock when it has detected 6+ satellites and the status LEDs are green before take-off? It's a software design flaw. If you have decent GPS such that it shows the slow blink Green LED status and tells me it has 7 satellites on the app, what is the excuse for thinking that home is 300 miles away? I flew in GPS mode and hovered perfectly for a minute or two before it took off onto the horizon. If the GPS location has been determined such that it is green before takeoff (which it was for about 5 minutes) and it can GPS hover, there is no excuse for not knowing where it took off from and thinking that home is 300 miles away. How does it not know where it took off from? It had GPS (as indicated by the slow blinking green lights and the on-screen satellite count), it knows when I turned it on, it knows when I hit the throttle, and it knows when it starts climbing. There is no denying it had valid GPS data, and no excuse for it not knowing where it took off from. The home lock system simply sucks. The implementation has avoidable gross inadequacies that cost me my drone. Also what's the point of trying to fly 300 miles to what is obviously an erroneous home that was registered days ago? Why even allow launch if home is 300 miles away? What's the excuse for not knowing the take-off location when 6+ satellites have been detected and the LED GPS signals are blinking green. It's a fundamental design flaw.
     
  20. Michigan_PI

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    You aren't going to like this answer but here it is anyway.
    The operator is responsible to ensure the system is functioning properly prior to take-off.
    It appears that you did not properly ensure that home-lock was set prior to take-off.
    Your craft was lost due to operator error/negligence.
    I am sorry for your loss but to say that it was a "fly away" and it was some defect of the machine is simply not true.
    Home-lock is indicated by RAPID flashing green lights and verified on the app. Additionally, if you plan on using home-lock on a regular basis or on a particular flight, it isn't a bad idea to test it, I usually do.
    Again, sorry for your loss.