At what altitude is supplemental oxygen required for crew members after 30 minutes?

Supplemental oxygen is required for crew members above an altitude of 12,500 feet after 30 minutes of exposure. This requirement is established to mitigate the risk of hypoxia, as the partial pressure of oxygen decreases with altitude, leading to a reduced availability of oxygen for breathing.

At altitudes of 12,500 feet and higher, individuals may experience physiological effects due to lower oxygen levels in the atmosphere. The regulation aims to ensure that crew members maintain adequate oxygen levels to function safely and effectively.

It’s important to note that while supplemental oxygen is not required below 10,000 feet, and only becomes mandatory for prolonged exposure starting from 12,500 feet, these thresholds are crucial for aviation safety. After 15,000 feet, supplemental oxygen is required for all occupants, regardless of the duration of the flight, which highlights the increased risks associated with higher altitudes.