What are the Oxygen requirements for unpressurized aircraft above 10,000 feet?

The requirement for supplemental oxygen in unpressurized aircraft is based on altitude and time of exposure. For flights above 10,000 feet, the regulations stipulate that all crew members must have access to supplemental oxygen. Additionally, when flights are conducted above 10,000 feet for more than 30 minutes, at least 10% of passengers must also have supplemental oxygen available.

This provision is primarily put in place due to the decreasing levels of oxygen at higher altitudes, which can lead to hypoxia—a condition where the body is deprived of adequate oxygen. The requirement ensures that both crew and passengers have a safer experience when flying at elevations where hypoxia may become a risk, allowing for sufficient oxygen availability in the event of an emergency.

Other options vary in their stipulations regarding altitude and time criteria, which do not align with the specific regulatory framework that specifies the need for supplemental oxygen for extended periods above 10,000 feet.