Fly-Away in Loiter non recoverable in Stabalize

I have a stock 3DR arducopter that has been flying great over the past year or so but two weeks ago had an issue that I’d like to try and figure out. I had flown 3 other 15 minute missions earlier on the same day with no issues. On this particular mission I lifted off in Stabilize and after 10 seconds switched to loiter. very soon after I noticed the Quad gaining altitude and moving rapidly away form my position. I switched to stabilize to try and regain control and was unable. The quad kept gaining altitude and moving away until it just dropped out of the sky.

The log shows a fairly drastic drop in NSats and a glitch in HDop at the time loiter started to act up. This could explain the loiter issue since the GPS may have been unreliable but I’m at loss to explaining the lack of control in stabilize. The control inputs do look rather jittery so it may have been control interference. This is my first time analyzing a log file and I was hoping someone else could take a look and confirm.

I do also admit there is a bit more vibration than I like, but this has not changed for many weeks. I’m waiting on new motor shafts and a new motor.

Thanks,
Charlie

GPS plot shows that it flow up over a building and landed. I’m thinking that’s not what happened.
This could be caused by GPS drift where it thinks it’s moving away and corrects by moving in the opposite direction.
Once you selected Stabilize mode can’t determine what went on since logging was set low and not much information in the logs. Vibrations were a little high but should not have effected this mode. Throttle out indicates you gave it some throttle and increased it’s altitude. Beyond that can’t determine what happened.

Mike

What are your values for these params?
FS_GPS_ENABLE
GPS_HDOP_GOOD
GPS_NAVFILTER
GPS_TYPE
GPSGLITCH_ACCEL
GPSGLITCH_ENABLE
GPSGLITCH_RADIUS
ARMING_CHECK