For how long can a pilot fly between 10,000 and 13,000 feet ASL without readily available oxygen?

The correct answer is that a pilot can fly between 10,000 and 13,000 feet ASL without readily available oxygen for a duration of 30 minutes. This regulation is in place to ensure safety for pilots operating at altitudes where oxygen levels begin to decrease and may potentially affect performance and judgment.

At altitudes between 10,000 and 13,000 feet, the risk of hypoxia increases, and the requirement for supplemental oxygen is established to maintain cognitive and physical abilities. The 30-minute time limit allows pilots to conduct short flights or maneuvers without the immediate need for supplemental oxygen, while still acknowledging that prolonged exposure to these altitudes without oxygen is not advisable. Beyond this timeframe, pilots should either be utilizing supplemental oxygen or be at a lower altitude where oxygen is more readily available.

Understanding this regulation emphasizes the importance of safety and physiological limits concerning cabin pressure and oxygen availability when flying at higher altitudes.