At what altitude must a pilot use supplemental oxygen for flights over 30 minutes?

The regulation regarding supplemental oxygen states that for flights above 12,500 feet MSL (Mean Sea Level) and up to and including 14,000 feet MSL, pilots must use supplemental oxygen if they plan to be at those altitudes for more than 30 minutes. This requirement is in place due to the decreasing availability of oxygen at higher altitudes, which can impair a pilot's performance and safety.

At altitudes above 14,000 feet, the requirements become stricter, as pilots are required to use supplemental oxygen at all times. Therefore, knowing this threshold is essential for understanding the oxygen requirements for safe flight operations in high-altitude environments.