A few months ago I was flying my DJI-550 Hex with APM 2.5+ and ArduCopter 2.9.x. It was flying in stabilize mode just fine after 7 minutes at an altitude of 20 feet it pitched forward (upside down) and augured into the ground. The crash broke several arms on my 550, the top of the 550 plate all my props, cracked the case on my RC receiver and other cracks and breaks on various components.
I've just rebuilt using a Turnigy Talon Carbon Fiber Hexacopter frame from Hobbyking and an Orange RX800X 8 channel receiver. All the other parts (motors, ESCs, APM, etc.) are the parts I had on my F550.
I did a reset on my APM 2.5+ and upgraded to ArduCopter 3.0.1. Did compass and accel calibration. All seemed to be good.
I took it outside for a test flight and when I powered it up, and tried to hover the copter pitched violently to the left and crashed.
Brought it in and replaced a broken prop; tried a few more times with the same results.
Does any one have any ideas on what would cause this? Where do I start to look?