FAR 91.211 sets three distinct oxygen thresholds pilots must know cold - here's what they mean, why they exist, and how to apply them in real flight planning.
Hypoxia's most dangerous symptom is euphoria - the feeling that everything is fine. Learn the FAA oxygen rules, TUC numbers, and why you must act before you feel impaired.
FAR 91.211 requires pilots to use oxygen above 12,500 ft after 30 minutes, continuously above 14,000 ft, and to provide it to all occupants above 15,000 ft.