Drone start reducing height in auto mode in 4.3.7 version

ArduCopter Copter 4.3
1

We are using the 4.3.7 version firmware(semi auto firmware), we observe that in auto mode the drone height start decreasing from the given altitude. Also we can control the throttle in auto mode. i was flying in poshold mode due to issue in auto mode. The drone had crashed while in poshold mode. I am attaching the log file related to this issue. Please help in this issue.
Note:
Flight controller: Cube orange
Version: 4.3.7 semi auto firmware

     [https://drive.google.com/drive/home](https://drive.google.com/drive/home)
2

Drive link has been attached above.

3

Am I correct that you have not done autotune and Harmonic Notch filters to your 23" propeller Hexacopter?
The drone z vibration is a bit high.

EK3_SRC1_POSZ, 3 GPS, any reason why GPS and not barometers?
EK3_SRC2_YAW, EK3_SRC2_YAW, 2 GPS. CubeOrange we usually set 0.

4

I have done the autotune and notch fliters but enable to trace the problem, Please see that i have correctly assigned the parameters in X,Y,Z directions. or any parameter to be added

5

if you have done it then it should not be these default values.
|ATC_ACCEL_P_MAX|38700|
|ATC_ACCEL_R_MAX|38700|
and your ATC_ACCEL_Y_MAX,9000 is unusual for 23" prop drone.

try to follow this guide.

after proper tuning and a good frame, if you still face height dropping, can consider this.

image

6

thank you for your time i will check and update you.