Which oxygen system is typically provided for passengers?

In passenger aircraft, the constant-flow oxygen system is typically provided for passengers. This type of system is designed to deliver a continuous flow of supplemental oxygen, which is crucial in the event of sudden cabin decompression or other emergencies leading to low cabin pressure.

The constant-flow system operates by supplying oxygen at a fixed rate, regardless of the passenger's need, ensuring that oxygen is readily accessible to anyone who may require it during an emergency. This is particularly important as it guarantees that all passengers can receive oxygen irrespective of their individual breathing rates or situations.

In contrast, other systems like the diluter-demand and pressure-demand systems, while efficient in certain applications (especially for crew members), are more complex and tailored for variable physiological needs. They may not provide the immediate and uninhibited access to oxygen that is necessary for a large group of passengers during emergencies. The demand system, specifically, requires a person to inhale to receive oxygen, which may not be practical in a chaotic or stressful situation like a decompression event. Therefore, the constant-flow oxygen system is preferred to ensure that all passengers have access to oxygen when it is critically needed.