What are the oxygen requirements at cabin pressure altitudes above 15,000 feet MSL?

At cabin pressure altitudes above 15,000 feet Mean Sea Level (MSL), supplemental oxygen is necessary for both flight crew and passengers to ensure safety and maintain adequate levels of oxygen in the bloodstream. At this altitude, the atmospheric pressure significantly decreases, leading to a corresponding drop in the partial pressure of oxygen. This can result in hypoxia, a condition where the body does not receive enough oxygen, which can impair cognitive function and physical abilities.

Therefore, regulations mandate that supplemental oxygen be provided to all individuals aboard the aircraft when operating above this altitude. This requirement ensures that both the flight crew, who must maintain operational control of the aircraft, and the passengers have access to sufficient oxygen for safe travel. Understanding this requirement is crucial for ensuring the health and safety of everyone on board at high altitudes.