At what cabin pressure altitude must supplemental oxygen be provided to passengers?

Supplemental oxygen must be provided to passengers when the cabin pressure altitude exceeds 15,000 feet. At this altitude, the partial pressure of oxygen in the environment decreases significantly, which can lead to hypoxia— a condition where the body is deprived of adequate oxygen.

The requirement for supplemental oxygen is outlined in aviation regulations to ensure passenger safety during flight. While other altitudes, such as 10,000 feet and 12,500 feet, have different requirements for crew oxygen availability, the 15,000 feet threshold is specifically when supplemental oxygen must be made available to passengers, emphasizing the importance of maintaining adequate oxygen levels to prevent incapacitation or serious health risks during flight. Additionally, at higher altitudes, the risks associated with low oxygen levels increase significantly, necessitating the regulation to protect all individuals on board.