I have APM 2.8 . I tried to lift up the quadrocopter and immediately crashed. After i connected to pc I saw that STB_PIT_P and STB_RLL_P set to 0. then i change to 4.500 and save them(try to set this numbers in Full parameter list and in Extended list) . then disconnected ant connected gain. And again same problem numbers were set to 0. All other settings are in place. only this after every refresh sets to 0