What should pilots ensure regarding supplemental oxygen equipment above FL350?

Pilots must ensure that one pilot wears a mask that provides continuous oxygen above FL350 because of the decreased atmospheric pressure and lower levels of available oxygen at high altitudes. When flying at these altitudes, the risk of hypoxia, a condition caused by inadequate oxygen supply to the body, increases significantly. Continuous oxygen is necessary to ensure proper cognitive and physical functioning, allowing the pilot to maintain situational awareness and manage the aircraft safely.

The requirement is rooted in aviation regulations and safety protocols that prioritize crew health and operational capability in environments where the risk of oxygen deprivation is heightened. Proper use of supplemental oxygen is crucial for safe flight operations at altitudes where the oxygen levels are insufficient for normal physiological function.