Supplemental oxygen

In plain English

At high cabin altitudes the required crew, and eventually the passengers, must use supplemental oxygen. Between 12,500 and 14,000 ft cabin altitude the required flight crew must use oxygen for any portion of the flight at those altitudes lasting more than 30 minutes; above 14,000 ft the crew must use it the whole time; and above 15,000 ft each occupant must be provided oxygen.

Key points

• 12,500–14,000 ft (cabin): crew uses O2 if longer than 30 minutes.
• Above 14,000 ft: crew uses O2 continuously.
• Above 15,000 ft: oxygen provided to every occupant.
• These are cabin pressure altitudes (for pressurized aircraft, the cabin altitude).

Common pitfalls

• Hypoxia is insidious and starts well below the legal limits — many pilots use oxygen earlier, especially at night.

*This is a plain-English summary for study only. The official 14 CFR text on this page is controlling — always read the current regulation and consult a CFI.*