My Quadcopter suddenly got into turmoil when recovering into Loiter Mode

hope you can help my problem, The quad suddenly got into turmoil during the flight and descended from 101 mtrs altitude to 57 mtrs, it just stopped descending when I switched to RTL and safely landed it… what do you think caused the turmoil?

I’m assuming this is for the log you posted in the Tuning Instructions thread (and sent to me)
There’s no actual serious warnings.

You pitch and roll PIDs are quite different, and in fact Pitch is what gets out of control first.
I think the problem is the tuning is not quite right, in conjunction with the weight imbalance that Dave mentioned earlier - and this leads to instability during decent. You can see in this graph the flight controller almost lost control a second time too:

You should definitely fix the weight imbalance and then probably set these:
ATC_RAT_PIT_P,0.10
ATC_RAT_PIT_I,0.10
ATC_RAT_PIT_D,0.005
ATC_RAT_RLL_P,0.10
ATC_RAT_RLL_I,0.10
ATC_RAT_RLL_D,0.005

Do a small test flight (dont go trying too much, small stick movements to check response) and if it’s still wobbly try setting those 0.10 values to 0.12 or 0.15 - you just want to get to a stage where you can run Autotune safely.
SInce it’s already flying, maybe set this too:
AUTOTUNE_AGGR,0.1

Here’s the guide:
https://ardupilot.org/copter/docs/tuning-process-instructions.html

There’s a spreadsheet to help:


Download a copy and put in your prop size and LiPo cells.

Thanks a lot shawn, i will try to change everything that you have said