What type of oxygen system do passengers typically use?

Passengers typically use a constant-flow oxygen system because it provides a steady supply of oxygen when needed, particularly in situations where cabin pressure drops. This type of system is beneficial in commercial aircraft environments where passengers might require supplemental oxygen, especially during emergency situations such as rapid decompression.

In a constant-flow system, oxygen is delivered continuously at a specified rate regardless of the user's inhalation or exhalation. This ensures that passengers receive an adequate supply of oxygen during times of need. Additionally, these systems are designed to be simple and effective, making them user-friendly for individuals without specialized training, which is ideal for passenger scenarios.

The other options provide varying methods of oxygen delivery, but they are not typically used in commercial passenger transport. For example, demand-flow systems require a person to inhale to receive oxygen, which may not be suitable for all passengers, particularly those who may be disoriented or panicked during an emergency. Pressure-sealed and automatic-release systems are specialized for specific aviation or medical settings and do not generally apply to the general passenger experience in commercial aviation.