When flying solo, what mode should the ISS be set to?

When flying solo, the ISS (Inertial Navigation System) should be set to the SOLO mode. This mode is specifically designed for operations when only a single pilot is flying the aircraft, allowing that pilot to have complete control over the vehicle's systems without interference from any additional input or systems that may be engaged when flying with a co-pilot.

SOLO mode streamlines the aircraft’s functionality, ensuring that all necessary parameters are focused solely on the single pilot's actions and decisions. This provides optimal performance and safety, as the pilot can manage navigation, systems monitoring, and any required maneuvers without the complexity or potential conflicts of inputs from another pilot.

Other options like BOTH or MANUAL may imply modes that could lead to complications in control or coordination that are not needed in a solo scenario. STANDBY mode typically indicates that the system is not actively in use or is temporarily inactive, which is not suitable during solo operations when continuous engagement with the flying systems is necessary.