For how long must flight crew above 10,000 ASL carry oxygen during flights?

Flight crew must carry supplemental oxygen during flights at altitudes above 10,000 feet for an uninterrupted duration of 30 minutes within the time frame of their flight operations. This regulation is in place due to the physiological effects of altitude on the body, which can lead to hypoxia—a condition that occurs when the body doesn't receive enough oxygen.

Carrying oxygen for at least 30 minutes ensures that crew members can maintain their cognitive and motor functions effectively should the cabin pressure drop suddenly. This requirement highlights the importance of preparedness for emergency scenarios, allowing the flight crew to manage situations that might necessitate quick decision-making and execution of safety protocols.

While other durations such as 10, 45, or 60 minutes might seem plausible, they do not align with the specific regulatory framework that mandates a minimum of 30 minutes of supplemental oxygen for flight crew operating above 10,000 feet to ensure safety and compliance.