In the context of ArduPilot Lua scripting, there is no simple vehicle:set_pitch() function for a landed state because the autopilot's internal takes priority over external inputs to ensure safety and stability. The "No Set Pitch" Challenge

Are you trying to during a specific landing maneuver, or are you encountering a script error when trying to assign a value to a pitch variable?

If you need to adjust the pitch—perhaps for a specialized vertical landing or to angle a camera/sensor while stationary—developers often use these methods: