I was wondering if someone could confirm a hardware failure from looking at this log for me?
APM 2.5 with internal compass
3DR Quad kit (essentially this one: http://store.3drobotics.com/products/3dr-arducopter-quad-c-frame-kit-1 but I bought it with the uBlox LEA-6 GPS module before the compass was included)
3S-4000mah battery (fully charged and balanced before the flight)
10x4.7 props (balanced but some minor battle nicks on them)
850kv blue motors
Moon Gel pads (double layer) under the corners of the APM and APM secured to top plate with rubberbands
3DR Telemetry radios
I have done all of the calibrations and scored a 7% on my compassmot test! :-) I do not recall my vibration test results but they were well within margins.
The day here was partially cloudy, about 55F (a nice summer day in Alaska!) with wind gusting up to about 15mph and about 10 steady coming from behind me as I faced the quad.
I had already done a successful flight previous to this one with no problems. I was testing loiter and RTL on the first flight as well as just flying around practicing circles and nose-in and nose-out orientations. I swapped batteries and allowed over 5 minutes between flights for the APM to warm up and settle out.
During this flight I was mostly again testing Loiter with a bit of RTL and some basic forward and back maneuvers along with side to side. Some friends dropped by while I was flying so I basically parked the Quad in a Loiter and talked to them while still keeping and eye on the quad.
After a few minutes of talking and loitering we all just watched the quad sort of dip one arm and fall from the sky. It wasn't a tumbling type of a fall, it was flat but sort of wobbly as it fell pretty much straight down. Luckily it had been raining for the last 5 days so the field I was flying over was really soft and there wasn't any real damage except for the landing gear which cracked. One arm/motor was buried in the soft dirt and were stopped but the other 3 were still spinning. Moving the throttle had no effect and trying to disarm didn't either. I thought about letting the battery run itself out but then decided to carefully reach under the quad and unplug the battery. As I think about it now I was probably still in Loiter mode and simply switching to Stabilize probably would've allowed me to disarm normally but it didn't occur to me at the time.
Anyway, that was my flight. I took a look at the log tutorial and to me it looks like when I graph the roll values and the pitch values that a mechanical error occurred but I am certainly no expert reading/graphing the log data. If someone could confirm this I would be very grateful.