Ok, so when using arming on a switch, airmode was active?
Sorry I have not use the switch arming but I have been meaning to reevaluate my arming procedures.
To explain what this does:
When you pull the throttle all the way to minimum, throttle wants all motors to go to minimum. Zero throttle, zero motors, zero thrust. But also zero roll, pitch and yaw.
If we want to control the aircraft in roll, pitch, and yaw while you have the throttle at zero we must give permission to the motor mixers to prioritise roll, pitch, and yaw over the throttle. We do this with ATC_THR_MIX_MAN. If we set it to 1 the aircraft can increase the thrust to hover thrust momentarily to control the other axis. If we set it to 2 we can use up to twice hover throttle to control the other axis.
So why do we set it to 0.1. This make it easy to land and prevents bounce caused by the aircraft aggressively pushing the first contact point back as it touches down. Instead the low throttle takes the athority away from roll and pitch letting the aircraft settle flat on the ground.
SAFETY FACTOR: This should always be set low during tuning. If an axis starts to oscillate on an aircraft with a low hover throttle and high ATC_THR_MIX_MAN, it can increase the thrust value above hover throttle and cause the aircraft to climb uncontrollably. During tuning you should make sure that hover throttle is set correctly or conservative low and ATC_THR_MIX_MAN = 0.1.