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  1. JulesTEO

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    Location:
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    First of all I'd like to introduce myself, I'm Jules from Mexico and a Typhoon H owner.

    I'm new to multirotors and the H is my very first one. (I know most people recommend to get a cheap "drone" to practice but I just couldn't resist)

    A couple of weeks ago I was about to practice (as I've been doing since I got it), everything had been going great, I've a couple of videos recorded with no problem, I've used POI, CCC, no gps flight, etc and every step had been going perfectly, however during my last flight something went wrong with the GPS (or at least that's what I've concluded)

    Unfortunately I accidentally closed the tab where I explained everything that happened in detail and lost everything, so I'm going to do a sumarized version.

    Just after taking off and holding position at low height (5m) the aircraft started floating away from my position, yawing and pitching by itself in a semi-circular path and gaining speed fast. I panicked and pushed the elevation all the way down, as I tried to lower it it went behind some trees and vehicles and when I lost visual contact I panicked again and sent it back up to prevent it from flying out of control at a person level. Once I regained visual at about 6 meters height I tried again to bring it down but it ended hitting wall at 1 meter height going 21 miles per hour (according to telemetry)

    Obviously my lack of experience had a lot to do with the escalation of the situation, any experienced pilot would've compensated for this behaviour, so the malfunction of the machine and my rookiness added up for a hard hit.

    I reviewed the flight using the FlyLogParser app on the ST16, and it shows very strange registry. It shows the aircraft in a fixed position where I took off, then it shows the H yawing and pitching but the position is still "stuck". It keeps showing a fixed position and just a couple of seconds before the crash it jumps to the actual position at the last moments before the crash. In a fraction of a second it jumps from the "stuck" position to the actual position which was about 60 meters away.

    Luckily nobody was harmed, but the H sustained some damage.

    I sent an email to yuneec informing the issue, and they told me they filed a case and were going to check the telemetry data. However 5 days later I had no response so I e-mailed them again. Their response was then:

    "Hello,

    We are reviewing telemetry right now and will get back to you shortly. Thank you


    Customer Care Yuneec USA Inc."

    That was about 2 weeks ago, and since then I have got no other response. (and I'm starting to think I'm not getting any answers any time soon)

    Since then I got to the task of repairing the machine myself, luckily everything seems to work fine, I could retrieve all the pieces and it was fixable with minimum spending.

    Anyway as I told you I had already typed the whole story in detail and it was very frustrating that I lost it, so if anyone is interested in further detail just tell me heheh.

    Here are some pictures from the day of the crash:

    [​IMG]
    [​IMG]
    [​IMG]

    And this picture is from earlier today:

    [​IMG]

    Only pieces replaced: Gimbal mount, one landing gear.

    It's ready to go back on the sky, (I already made a test flight without the camera) however I'd appreciate more insight from Yuneec into what happened, because the last thing I want is for the same situation to happen again.

    Just wanted to share this story with you, tell me what you think about this

    Greetings!
     
  2. Steve Carr

    Steve Carr Moderator
    Staff Member

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    There has been a GPS problem on a few H's and it sounds like that is the case here. At this point I would say the GPS will be unreliable and needs to go back to Yuneec for repair. Did you email Yuneec at the US facility? I suggest you send another email to rborders@yuneecusa.com and explain the situation and if possible attach the flight log file for that flight. Some people have found that by turning off the GPS in flight they were able to regain control and bring the bird back home but that only works if you have enough altitude and time to do it.
     
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  3. DroneClone

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    If your main flight module/IMU/GPS are malfunctioning do to a component , it will most likely do it again ! Unless it was a electrical interference at where you flew! I would have sent it in for Yuneec to fiquire it out and fix under warranty
    I had the same uncontrollable drift from a 8 ft hover and have been flying for years. There was nothing I could do to stop the drift or land it !
     
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  4. banned user

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    Agreed it probably needs a GPS replacement, I would persist until you get an RMA, you might have to pick up the phone too, I'd also ask and put a note in the box pointing out the repairs you already made and have them check those repairs and continue the warranty. Hope this gets sorted quickly!
     
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  5. HedoBum

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    I just got a Typhoon H and experienced much the same problem on my second flight.
    I was in the back yard and surrounded by buildings all around which might have had something to do with this incident. I had just brought it back in and I was attempting as smooth a landing as possible with so little hours under my belt. It was hovering at about the 4' level and I wasn't touching the ST16 when the bird just suddenly listed down and off to one side. I went for the controls but I was too late and it crashed into a fence. Luckily I got away with only minor damage (couple of broken props and a little scuffed up landing gear) but I can see how it could get much worse. The GPS was my first thought and maybe I was on point but we'll see in future flights. The next 2 flights were carried out in an open field and both seem to run flawlessly running the full gambit of flight modes and tasks. Landing gear works fine and all arms solid.
    I'm not sure if I should report it to Yuneec or not as there doesn't seem to be any real damage. I'll see how things go in the coming flights.
     
  6. JulesTEO

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    Location:
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    In my case I'm still wondering what could've been the problem. I mainly attribute it to a GPS problem, but telemetry data also shows unusually low values on the Recieved Signal Strength Indicator (RSSI). At that location there's a large antena, so I believe interference could've played a factor as well.

    I fixed my unit after this incident and have never had another similar issue, but ever since I do wait until I have the most possible sats locked (ideally 20) and I always turn on the unit at the point of take off. The day this happened I had 18 sats, but I turned the H on in one place and later moved it to where I took off, in the process of moving it I got 2 or 3 GPS lost warnings, which I believe contributed to the problem.
     
  7. PatR

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    Location:
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    A lesson for all in this is once powered up, don't move the H to a different location. Turn it off, carry it there, and power up again.

    Loss of GPS does not cause a crash. You can fly all week without GPS. Inaccurate accelerometers can cause a crash. Moving an H before they are fully established after boot up will make them so.


    Sent from my iPhone using Tapatalk
     
    #7 PatR, Nov 14, 2016
    Last edited: Nov 14, 2016
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  8. JulesTEO

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    Location:
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    Hello guys, just an update on this issue,

    As I said before, back when this happened I repaired my H myself instead of waiting for Yuneec to solve everything, and ever since I have had no other issues like this "fly away". Since this happened I never move the H after I've turned it on. Not even after it has booted and locked satellites; Always turn on and wait for GPS lock at take off spot.

    Anyway, I did contact Yuneec at the moment, I provided flight logs, pictures, explained everything that happened via email, even explained that I managed to repair the unit (I purchased a gimbal mount and landing gear struts) and also mentioned that it was flying without issue after the repairs but was still operating with 2 damaged, though functional arms.

    After a lot of back and forth emails they agreed to provide the damaged parts under warranty! :D:D It took a very long time since the H has been flying perfectly so I wasn't very insistent on the matter heheh.

    I wanted to share this update with you as my positive experience with Yuneec CS

    Even though I've had already my share of mishaps with the H I'm still very happy I chose it as my first UAV! I feel that I still learn from it every time I go out for a flight! I just cant understand why the Yuneec and the H are still so underrated.:rolleyes:

    Thanks a lot for the tip!!
     
    Steve Carr likes this.
  9. HedoBum

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    That's good to hear. I had a similar issue with mine after an update (October issue). Everything was fine when I did my calibrations and initial flight. Then the UAV unexpectedly dipped and veered off into a lamp standard. Knocked the camera and gimbal free, which fell to it's death. I don't think I have the essential know-how to fix it either. Hopefully I have the same experience with yuneec c's. Fingers crossed.
     

    Attached Files:

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  10. Rubik

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    I
    Jules, I'm glad that you are back in the air.
    I had a similar experience with unexpected flight behavior after dozens of flights without problems. I was at a new location near waterfall and a large steel RR bridge but it was close to a previous successful flight site. What was I thinking? I'm pretty sure the compass was confused by the mass of steel. I had very little control but managed to make a hard landing nearby without flying away. Tore the camera away from the gimbal.
    Was there any large metal object, cable or building near your take-off location? I'm curious how many fly-aways are caused by confused compass. I will be checking with my iPhone compass at any new location.
     
  11. JulesTEO

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    Location:
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    Thanks, although technically I was "grounded" only for a couple of weeks after the incident hehe.

    There was a Huge antena very close to my location, I did notice very low RSSI values on telemetry data when flying at that location, but I flew several times with no problems at all (I hadn't noticed the low signal values until reviewing log files after the crash). However the flight data did show unusual GPS behavior before the crash, telemetry shows normal signal, no errors or warnings, but somehow it shows a "Stuck" GPS position.

    That is the actual antenna:
    [​IMG]

    In regards of the metallic structures, recently I went out to get some footage, and I was attempting to take off from a metallic bridge-like structure. Every single time I took off I got a Compas Error Warning no matter how many times I calibrated.

    I decided to take off from off the bridge, and even though I was just a few meters away from the structure I calibrated again the compass and the error was gone completely.

    [​IMG]
    (Orange spot, constant Compass Warning during take off, Green spot, no compass error)
     
  12. Steve Carr

    Steve Carr Moderator
    Staff Member

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    Yup, never launch near any metal structure. It confuses the heck out of the compass.
     
  13. chiloschista

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    It just takes a few seconds to record the offsets. That's the blinking at start up. When it states RC ready you can move it all around. It's the very first few seconds that are mandatory.
    Satellites number is another relative value. Where I live it hardly goes over 12. It's all about DOP, especially HDOP.
    Losing GPS while moving it is probably due to the body, especially a hand over the GPS module, which can easily block several satellites as GPS signal is really weak in general.
    Ric
     
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  14. JulesTEO

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    Location:
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    I agree on the part that the GPS loss was due to holding the unit from the top and covering the GPS when moving it around. However I attribute the mid-flight malfunction to those 2 gps losses/recoveries when moving it around before takeoff. It was the only variable from all previous flights (and all the next ones ever since the crash).

    In that incident I didn't take off without GPS, I had a 18 sat lock, ready sign on angle mode. Everything seemed good to go. However, somehow the GPS location glitched, even the Parser app shows a weird pattern which I will try and upload tomorrow in case anyone is interested.

    I can't know for sure if it was just a glitch that was ever since addressed on later firmware updates or just was randomly triggered as I never got a straight an answer from the tele-data from Yuneec.

    I'm still flying the very same machine, so I try to be very careful not to replicate the same scenario from back then. That's why I now prevent those GPS loss situations and instead wait for a stable lock at takeoff site. If I have to move it around I turn it off, move it and then turn it back on.

    Greetings!