During a flight above 25,000 through 35,000 feet MSL, unless each pilot has an approved quick-donning type oxygen mask, what is required?

• A. Both pilots must wear oxygen masks at all times
• B. At least one pilot at the controls wears a mask that either supplies oxygen at all times or automatically supplies oxygen when the cabin altitude exceeds 12,000 ft, and the other pilot has a mask connected and ready
• C. Oxygen masks are not required at these altitudes
• D. Crew members only need oxygen masks when the cabin altitude exceeds 14,000 ft

Answer: (B)

At these high altitudes, oxygen supply and rapid access are critical for pilot safety in case of a decompression. The rule is designed to ensure redundancy so a pilot can get oxygen quickly if the cabin pressure changes or equipment fails. One pilot at the controls must be wearing an oxygen mask that provides oxygen continuously or automatically when the cabin altitude climbs above 12,000 ft. This setup guarantees immediate protection for at least one pilot even as the other pilot prepares to don a mask. The second pilot must have a mask already connected and ready to be donned, so there’s no delay in getting oxygen to both crew members if the situation worsens. This pairing ensures both pilots have prompt access to oxygen and maintains safety margins during high-altitude flight.