What minimum percentage of passengers must be provided oxygen when flying between 10,000 and 13,000 feet ASL?

When flying between 10,000 and 13,000 feet above sea level, regulations stipulate that at least 10% of the passengers must be provided with supplemental oxygen. This requirement is in place due to the decrease in atmospheric pressure and the corresponding drop in oxygen availability at these altitudes. As the altitude increases, the likelihood of hypoxia, or oxygen deficiency, increases for unacclimatized individuals, making supplemental oxygen necessary for safety and health during flight operations.

The specific percentage aligns with aviation safety standards aimed at ensuring that some passengers have immediate access to oxygen in case cabin pressure is lost or if they begin to experience symptoms of altitude sickness. This rule is particularly relevant in commercial and certain private operations where carrying a number of passengers is involved, emphasizing the importance of preparedness for emergency situations.

The other options reflect incorrect minimum thresholds and do not align with established aviation regulations for passenger oxygen requirements at these altitudes.