3DR Y6 Loiter, then crash

[hoschi]

Hi together, I need some help…

Yesterday, I did a testflight with my Y6. I was flying in stabilize mode and then I switched to Loiter, everything was ok. Then I switched back to stabilize.
Later I did the same again, but then went something wrong. The Y6 fell from the air to the ground and went again back up, I switched back to stabilize to get control back. I landed and checked all parts, everything was ok. Because I did not know what happend, I tried again to get in loiter mode → Same behavior again! But now the GPS-Mast broke and one of the propellers cut the cables from the GPS

So this is the 3rd flight I had, I’m now a little bit scaried about this behavior, because I don’t know exactly what was the problem. I can imagine, that this problem description from http://copter.ardupilot.com/wiki/altholdmode/#Controls could be the case:

“3. The motors seem to stop for a moment just as AltHold is engaged but then it soon recovers. This normally occurs when the pilot enters AltHold while climbing rapidly. The target altitude is set at the moment the pilot switches into alt hold but because the vehicle is rising quickly it flies above the target. The aggressive altitude hold controller then responds by momentarily reducing the motors to near minimum until the copter begins falling back to the target altitude. The workaround is to enter AltHold while the copter is flying at a stable altitude.”

But I’m almost sure, that the Y6 was not climbing rapidly while I was entering Loiter mode.
I attached the Logfiles of my flight. Can somebody read them and tell me what went wrong? I tried to understand the Logs, but I’m not able to get the important information and understand the relations between the single data sources.

Thank you in advance and sorry for my bad english
Hoschi