At what cabin pressure altitude is oxygen required for crew for any duration, according to the guidelines?

• A. Above 12,500 ft MSL.
• B. Above 14,000 ft MSL for any duration.
• C. Above 15,000 ft MSL.
• D. Above 18,000 ft MSL.

Answer: (B)

As cabin altitude climbs, the air you breathe has less oxygen, so the risk of hypoxia grows. That’s why aviation rules set specific thresholds for when oxygen must be available to the crew. The requirement that oxygen be provided for the flight crew for any duration kicks in at a cabin pressure altitude of 14,000 feet MSL. Beyond this point, you can’t operate without immediate and continuous access to oxygen for the crew, even for a short trip or depressurization scenario. The other figures relate to different, usually time-based or context-specific, oxygen rules, but they don’t establish the “any duration” standard for the crew.