• Logs show a power failure to all motors - RCoutput is increased but no response in altitude - My interpretation would be main power failure.

  • I had a similar problem on my APM. Twice the copter fell from the sky luckily the second was during a post build test so she only fell 3 feet. Turns out the XT60 connector on the power module was worn and would sometimes lose connection.

    • I am sorry to hear that. I am not using Power Module and the PDB connects to batteries using two EC5 connectors.

  • I am using Pixhawk. 

  • Hello Gary and thanks for the reply. It is a custom built hex. Yes, the ESC's are soldered directly to the PDB. I did take the whole copter apart and everything is just fine inside - like new. The PDB is 250A rated Vulcan PDB which is also more than enough for the hex (motors draw 6x30A max). 

    The batteries are OK. I measured the Internal Resistance - all cells are <5 mOhm, which is great. I've also done two flights with the hex after checking all details/connections and it flys great. First flight was 19:33 and the other one 12 min. I did have to replace all props, one landing leg and IMU on the gimbal + the safety button. 

    I can firmly say that it was not caused by a bad solder point on the PDB and batteries are not to blame either.

    I suspect, that one of the following things failed/happened:

    *Safety button defect (contact for 3 sec to disarm the copter in air)

    *Some kind of Pixhawk error

    *RX error

    Any thoughts? 

    • I had about the same thing happen to me yesterday.  (my post is the "crash log diag" thread here in the 3.x section). 
      My logs abruptly end, and my copter fell from the sky. 
      EVERYTHING in mine was directly soldered, so nothing came loose.  Battery is the only thing that was on a plug, and I know it was firmly plugged in when I took off.  Plus the two people who were with me swear they saw the lights still on (my navigation LED's) while it was falling.  (Don't know for sure, though.. I didn't notice). 

      I hope you (we) figure it out! 

      • Perhaps different issues,, if your log is abruptly end, your controller probably loose current; MR has a complete log without errors, not current problems, I had in 3.15 MR problem when I switched to land from pos hold, motors stopped in the air, and it was solved in 3.2.1 firm and never had again; that the reason that, if you don't find your problem I suggest to try 3.2.1 with carefull but, perhaps solve your problem, about safety button I don't know, I have APM, perhaps someone else can tell us if logs show when that button is activated?

  • Really strange, your current look's well, any errors in your log, did you try 3.2.1 ? perhaps better.

    • Thanks for the answer. I have not tested 3.2.1 yet. Testing every firmware in hope that it will not happen again is not the most economically efficient way to deal with the problem.

  • Looks like you briefly lost RC connection and probably didn't have a failsafe set. 

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