During a high altitude, out of sight FPV flight, I got disoriented and went out of both radio(Turnigy 9XR) and FPV Tx range, after about 3-4 minutes after take off.

I had 4S 2650mAh battery on it, which was consistently giving me about 10 mins of throttle time.

Failsafe on the APM was active! but my quad never came back. After hours and hrs of search, I couldn't locate it, it simply vanished. (I live in FL so there are lots of water around). Bermuda triangle may be??

I just saw an other failsafe discussion, whether it works or not, so I thought I should put it out, my experience with Failsafe was not a good one and cost me quite a lot of money and time (and sweat building and tuning the quad that I lost)

I must admit I never tested the failsafe before, I just assumed it "works".

Lessons learned: do not trust failsafe and never go out of sight even if with FPV.


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  • Sorry that you lost the craft Mural,

    One thing I have learned is always activate GeoFence radius and ceiling to the limits of your FPV manufactures rating, so if you get a flyaway or go past FPV limits, it should fly home if it hits the boundaries.  I have hit it 2 times and worked great for me.

    I know its not helping today but for next time.  I live in Tampa and yea, loads of water, if your near we can fly over and look for it.


    • I just learned about Geo-fence myself and set it up now.

      One thing that guys with a lot of expense invested in their models might keep in mind is that it should be possible to DF (direction find) the model IF the battery is still working for a while on the ground. A cheap 2.4Ghz yagi (DX has them) or 5.8Ghz panel antenna could be used to 'find' the video link signal by walking out on the last known bearing and panning it around for signal.

      If you happen to have an FrSky telemetry RX fitted, you can attach a 2.4Ghz yagi to the FrSky TX and use the RSSI meter to DF the lost model. If it's down in tall grass or a wooded area you may need to be less than about 300m away to get a sniff of signal again. 
      I also notice that if the FrSky RX telemetry link (with my APM data streaming) is lost, my Taranis keeps the last good GPS fix on the third telemetry screen. That might get somebody close to where the model is if you transfer the coordinates to a handheld GPS or phone with a GPS app.

      I guess all this would rely on the model not crashing it's battery out when it goes down, and having bought the suitable DF antennas beforehand :)

      One last thought. It's not too hard to use one of the $5 10mW 433Mhz data modules that are around on Ebay etc to make an independent homing beacon running on a button cell. You'd pulse the data pin with a 555 timer or a PIC micro etc, and use a $40 ham radio receiver to receive the signal. A bit like the way people track hunting dogs or wild animals.

    • Sorry for your loss! I just added a TK102B GPS tracker to my quad. Now I can locate it even if it takes off. Location is pretty accurate!
  • Sorry for your loss.  

    Next time do as we do and test the return to launch and set up some criteria for triggering RTL.  When things go bad disoriented or otherwise, have it RTL and auto land.  

    Last year my brother got disoriented and flew out of sight.  We knew exactly the bearing yet it took us a day of searching to find it only 1/2 mile downrange.  Those copters are tough to find.  After that mistake the RTL is set up and ready and no issues since. We test the RTL with the radio turned off!  It works great.

    So when a problem - Turn off your radio if all else fails.

  • I definitely trust my fail-safe. If set up properly, it works fine. I fly mainly fpv and on every flight I will test the RTL and occasionally turn off my radio to test the fail-safe. It works and I've got a repeater that connects to my 2.4GHz rx that then transmits through my ezUHF. I can turn off either the repeater (effectively breaking the connection) or turn of my controller. Either way fail-safe works. It's easy to test if it's going to work by using the fail-safe section in mission planner.

  • Ouch man... that's harsh. I've been away from working on my quads for a while, but I think it's time I jumped back in. I really want to work on getting FPV working also. It's time to do a little more reading!

  • sorry for your loss man, but you gotta admit, wiki says right away to check failsafe operation before relying on it (not because of apm doesn't know how to stir your copter home, but because it is sometimes tricky to get the message about lost link to apm).  properly tuned copter comes home...  I have very positive experience with it. radio failsafe is something you need to setup properly on your transmitter/receiver first than activate on apm. also if no GPS lock when armed quad doesn't know what the home is. 

    again, sorry bro for your loss, everyone is prone to learning stuff the hard way.  hope this post will highlight the importance of setting up properly and checking failsafe for everyone's benefit.

    • Thanks.. I had the GPS lock before take off so home was set.. And this one I had lost was the one I was working on for almost 6 months, and was very stable, lately made it even better by using the auto tune feature..

      Since I've done 10's of autonomous missions with it, and the RTL "always" worked, I assumed FailSafe will work.

      As a firmware developer in my previous life, I should have know never to assume..

      And I agree, FailSafe turns out to be the most important feature to be tested 1st thing before going onto missions and out of sight flights.


  • and one important part.....range test, and know the limits

    • Thanks.. Now I know.. Currently testing an IRIS.. That baby is going no way out of my sight..

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