During a test fight I noted that the modes I had programmed in setup did not seem to operating correctly.
I have APM 2.22 installed in control board.
I had " Manual, Stability and RTL " set in the 3 position mode switch. the first 2 modes seemed to work OK but RTL was not working and appeared to be circling.
I checked the download of the flight LOG and found the mode had been changing into ' Circle ' mode on several occasions and did not show a switch to 'RTL' mode even though 'Circle' selection was never setup .
I have set the mode switch positions to exactly the correct pulse-width as specified in the manual.
What is the best way to identify what is the problem ???