Arduplane 3.7.1 auto throttle issue

i m using arduplane 3.7.1. i m facing auto throttle issue on loiter and auto mode .i set airspeed as 18m/s it maintaining this airspeed for about 10 min after that automatically the ground speed reduced to 8m/s and plane stalled and crashed.

i changed airspeed and calibration too,but i had same issue for next flight,changed ESC too.

i tried with new pixhawk setup as old one with same firmware AR 3.7.1 even though had same problem for that flight also.

what could be the issue or i have to change the firmware

please post dataflashlog, or would you like some wild guessing ? :slight_smile:

if it did it for 10 minutes then something happened and I am forced to guess I would say it overheated.