What is required for operations at cabin pressure altitudes exceeding 15,000 MSL?

For operations at cabin pressure altitudes exceeding 15,000 feet Mean Sea Level (MSL), supplemental oxygen is required for all occupants of the aircraft, including passengers and crew. This is primarily due to the physiological effects of reduced atmospheric pressure at higher altitudes, which can lead to hypoxia—a deficiency in the amount of oxygen reaching the tissues.

At altitudes above this threshold, the partial pressure of oxygen in the cabin air decreases significantly, making it difficult for the body to obtain enough oxygen with normal breathing. As a precaution to ensure safety and maintain adequate oxygen levels, regulations mandate the provision of supplemental oxygen for everyone onboard when operating at these increased altitudes.

This requirement is in place to ensure that all individuals, regardless of their role in the aircraft, have access to sufficient oxygen and can maintain their health and performance during flight. The inclusion of the entire passenger load reflects the understanding that even non-crew members may experience the effects of altitude, thus promoting the safety and well-being of all occupants.