I programmed the following mission:

It is a quad, 3DR frame, nothing fancy, APM running V3.0.1.

It executed the auto mission until waypoint 3 then I saw the quad go down in an apparent controlled manner (it is not like i lost a prop) still moving toward waypoint 4, as if the quad wanted to land or something.

This is the google earth picture of the auto mission until interrupted at waypoint3:

I think I then switched to stab mode to recoup its descent but it crashed flipping upside down. I broke the telemetry module (antenna connector) in this crash.

Can anyone help me diagnose what happened and caused this strange crash ?

I see no reason : motors ok, propellers ok, battery was far from empty, I do not think I broke the geofence, ...

I looked at the onboard video and at the moment of the incident I hear a drop in motor power. Looking at the battery voltage it is not below the ESC soft power cutoff though. So I do not know what happened.

here attached the log and kmz files

2013-08-07 15-03 77.log

2013-08-07 15-03 77.kmz

2013-08-07 14-18-42.tlog