Ok so I'm flying around this morning for the third time ever and I was getting pretty aggressive with speed and climb outs in stable mode when I noticed my quad was loosing altitude and became unresponsive luckily I was close to the ground and it didn't come down to fast almost as if it was in land mode? it managed to flip over on its top and when I finally got to it the apm was disarmed and the blades were spinning super slow and there was a slight shrill/beep from the motors…… I wasn't able to arm the apm the only way I could was by unplugging main power and re-plugging main power after that I was able to re-arm and fly for about 5 more minutes before it did the same thing I wasn't far away from me so I don't think it was a radio range failsafe …….. after re-booting and re arming I was able to fly for a minute or so then my battery monitor started to beep so I landed. could this have been a brownout?

apm 2.5

3.0.1 firmware

4500 mah lipo

q-brain 25 amp esc

turnigy 9x "stock"

hobbyking q450 frame

tuurnigy multistar 2213 -935 kv motors 

10x4.5 props

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  • Interesting, I had the same problem a while ago. I Never actually spent time to diagnose the problem because it only happened a couple of times with really aggressive flying but this may explain what was happening to me as well.

    I wonder if it is possible your RX unit suffered a brownout (or vibration to the RX unit power connection during flight) but the APM board did not. I'm not much of a log reader but i see at 12350 MODE,LAND immediately followed by ERR 5,1 then later followed by ERR 5,0. The ERR 5 seems to indicate a throttle failsafe. (

    I'm certainly far from a log parsing expert so I could be way off here but it sounds very similar to behavior I saw a while ago.

  • LAND mode is usually initiated if you lose a GPS lock., but without a GPS module, not sure why it does this

  • My quad is doing this as well. Im getting about three minutes flight time on a 2200mah battery. When I recharge the batteries they are only half discharged. 

    I wonder could it be a matter of voltage monitoring error.

  • I think the dataflash log will be required in order to verify Neuro, can you upload that for the smart guys to look?  Also, if you wanted to try and examine yourself, there is an article on how to determine if a brownout happened here.

  • Do you have a GPS module fitted?

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