First let me say that I will always be a "newbie". I've been flying my 3DR quad for about 6 months and just when I think I get it figured out and seemingly flying well something weird happens and it falls out of the sky. Today I did a simple flight to tweak a new brushless gimbal (I had one previous flight with the gimbal). I took off, went from stabilize to loiter and loitered for about a minute, went back to stabilize and flew a little further out, went back to loiter for another minute, went back to stabilize and then RTL using channel 7. The quad flew back at current altitude (25M), started its descent and then just tumbled out of the sky. I wasn't using telemetry and don't have a log file.

Prior to the flight I had lowered my land_speed from 50 to 39 cm/s as my landing descent on my last flight seemed a bit fast. Also, I noticed that my sonar was disabled and I enabled it.

I thought I would at least have a fantastic video, but either the crash damaged the file being written or I neglected to start the video....

Anyone have any thoughts? I realize this isn't much info.

Thanks for any help.