I can't find which Fail Safe switched before crash

3DRobotics DIY Quad - Pixhawk Autopilot

I have only been flying for about a week, and have had my first catastrophic crash. I was testing the Auto mode and having the quad fly a pre-loaded mission. Shortly into the mission the quad automatically switched into RTL (return to launch) mode. (I spell some of these out for newbies like me). I looked at the mission planner’s Flight Data screen, and didn’t see any ‘Fail Safe’ warnings or any reason for the RTL to be automatically activated. I thought it might have something do do with an error in the mission file, so I switched it back into Auto mode. About 15 sec later it switches back to RTL, and i switch it back to Auto. This happens a couple more times. I know… this was a stupid move, I completely agree, and as it turned out, a very costly mistake. The last time I switched it out of RTL mode, the quad flipped over and fail out of the sky landing on its top.

I have RTL as an action for all Fail Safes.

I looked back over the mission planner’s tlog and found the point where it automatically went into RTL mode, and there was a ‘Fail Safe’ message that popped up for a second or two, but didn’t stay. My question is, finally, how can I find out what caused the Fail Safe warning. I am beginning to believe that it was caused by a intermittent loss of Remote Control signal due to low battery. This would explain why it crashed when I switched from RTL into Altitude Hold mode. However, I don’t know where to look in the tlog to find the cause. I have attached the tlog file.
Any suggestions?



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