I say unexplained , although i actually caused the crash. I was mapping a test area that I frequent. The flight went well but at the end during the final stage of the return to launch, the aircraft stopped descending at 10 mtrs and held there. I thought it was the condition where it gets a bit stuck at the final descent stage before landing, but after about 20-25 seconds I decided to intervene. I had already lowered the throttle preparing for landing so I raised it back to 50% and switched back to Stabilize mode. The copter fell from that height with no throttle. I looked at the logs and it did not think it was at 0 alt nor was the RTL final alt set above zero. I've attached tlogs if anyone would have a thought. 

2015-01-18 11-59-41.tlog

2015-01-18 11-59-41.tlog.jpg

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  • Hi Sean,

    I had similar experience earlier in the game.

    How do you power the back end of the flight controller to the esc's control leads? 

    I found that I could fly many times without putting a BEC line into the output side (no J1 jumper) that you can get the esc's to fire up most of the time but on occasion, they would quit at inexplicable times! ( Earlier on i did not realise my ESC's did not have a BEC) 

    Hope that helps?

    • Typically i only plug the signal lines into the Pixhawk. I use high voltage 6S-8S ESCs that often dont come with BEC. I am powering the + bus with a 5V power supply for the camera trigger. It was not a smuch of an eqipment failure as it stopped descending at 10 meters (closer to 3-4 meters in actuality). The crash occured when I switched back into stabilise with the throttle at approx 50% 

    • Developer
      See https://pixhawk.org/users/actuators/pwm_escs_and_servos on why you need to connect the signal GND wires to your escs, I'll try to look at your log later.
    • Thanks Bill,

        I'll make this change . Do you think this may have led to the stalled landing procedure or perhaps the loss of throttle when I switched back to STAB. I look forward to any insights you have about the log.

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