If anyone is willing, I would appreciate assistance in analyzing and interpreting a dataflash log to see if I can determine what caused my IRIS+ to crash.
I only have 15-20 flights experience with most of those being autonomous survey flights. That is what the crashed flight in question was. I had already flown 2 autonomous missions on this day with no issues and had flown this particular mission in the past.
As the copter went to make a turn between waypoints, the props/motors changed sounds dramatically. Sounded like it was laboring or even sputtering. At that point it began to lose altitude. I first attempted an RTL with no luck and it was on the ground before I was able to switch to Loiter or Alt Hold to attempt manual control.
In the attached log, I can see several issues with vibration, GPS glitches, and potential mechanical failures, but unfortunately I do not have enough experience to adequately interpret the information I am seeing in the logs to determine the root cause(s) of the crash. Any assistance is greatly appreciated.
BTW, while I haven't attempted another flight yet, I appear to have gotten very lucky with the damage done. 100m drop into a flooded rice field and potentially only a broken prop and leg. Shell, GoPro, and two of the legs never went into the water! May have some motor damage on the two that were in the water. We'll see.
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The vibrations were bad at the point it made the turn so it looks like something may have come loose or something got stuck in the motors. It doesn't look like a complete motor failure as it seems to slowly loose altitude and the PWM to the motors go from max to min several times on the way down. With a complete motor failure or loose prop that motor goes to max and the other side goes to min.
One prop was snapped clean off on both sides, but I assumed that happened as it hit the ground on that side of the copter with the props still spinning.
Thanks again.