192.168.l.254 192.168.1.254

Hello everyone,
The flight mode channel is set to channel 8 by default on Mission planner. I want to change it to channel 5. The mission planner docs mentions it can be changed using the FLTMODE_CH parameter but it is not found in the full parameter list.
Does anyone have an idea what to do ? 192.168.l00.1

Copy from the ardupilot/copter wiki: https://ardupilot.org/copter/docs/common-rc-transmitter-flight-mode-configuration.html