What should the oxygen diluter be set to during a smoke in the cockpit situation?

In a smoke-filled cockpit situation, it is crucial to prioritize the safety and functionality of the oxygen supply for effective breathing. Setting the oxygen diluter to 100% is the most appropriate choice because it ensures a continuous flow of pure oxygen, which is essential in a high-risk environment where smoke could contain harmful gases or reduce the availability of breathable air. This setting helps to prevent hypoxia, ensuring that the crew maintains their cognitive function and physical capabilities in a challenging situation.

In contrast, options that involve mixing pure oxygen with ambient air, such as 50%, 75%, or ambient air, dilute the oxygen concentration. This can lead to insufficient oxygen levels, increasing the risk of disorientation or incapacitation due to smoke inhalation. Therefore, when dealing with smoke in the cockpit, utilizing 100% oxygen is essential for maintaining optimal breathing conditions needed for effective communication and operation of the aircraft.