If either cockpit regulator supply lever is set to ON, what must be OFF for OBOGS to be disabled?

To disable Onboard Oxygen Generating System (OBOGS) functionality, it is essential that both cockpit regulator supply levers are set to OFF. When either of the supply levers is set to ON, it allows for the flow of oxygen from the OBOGS, which means that the system will continue to operate and provide oxygen to the pilots.

When both supply levers are OFF, it cuts off the airflow and thus disables the OBOGS, ensuring that no oxygen is supplied. This design ensures safety by preventing inadvertent operation of the oxygen system when it is not needed. The condition for disabling OBOGS necessitates both supply levers to be OFF, emphasizing that having both engaged would not meet the requirement for deactivation.

The options referring to either oxygen concentrators, emergency oxygen cylinders, or water separators relate to different functions and components within the oxygen system, but do not directly affect the operational status of OBOGS when it comes to the cockpit regulators. Thus, understanding the role of the supply levers is critical to managing OBOGS effectively and safely.