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Cabin pressure altitude is between 12,500 and 14,000 feet MSL. After how long must the required crew use oxygen?

After more than 30 minutes at those altitudes.

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  1. As soon as you pass 12,500 feet
  2. More than 60 minutes
  3. More than 30 minutes ✔

Why: Under 14 CFR 91.211(a)(1), the required minimum flight crew must use supplemental oxygen for the part of the flight over 30 minutes at cabin altitudes above 12,500 and up to 14,000 feet MSL.

Huh, didn't know that: The AIM says to use supplemental oxygen above 10,000 feet in the day and above 5,000 feet at night for best protection.

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Why didn't the passenger know how to use an oxygen mask? Because the flight attendant didn't ex-plane it properly.
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References

Answer: More than 30 minutes. Under 14 CFR 91.211(a)(1), the required minimum flight crew must use supplemental oxygen for the part of the flight over 30 minutes at cabin altitudes above 12,500 and up to 14,000 feet MSL.

  1. eCFR 14 CFR 91.211 Supplemental oxygen www.ecfr.gov/current/title-14/chapter-I/subchapter-F/part-91/subpart-C/section-91.211
    of more than 30 minutes duration
    Checked 2026-10-11.
  2. eCFR 14 CFR 91.211 Supplemental oxygen www.ecfr.gov/current/title-14/chapter-I/subchapter-F/part-91/subpart-C/section-91.211
    uses supplemental oxygen during the entire flight time at those altitudes
    Checked 2026-10-11.
  3. AIM chapter 8 section 1, Fitness for Flight www.faa.gov/air_traffic/publications/atpubs/aim_html/chap8_section_1.html
    pilots are encouraged to use supplemental oxygen above 10,000 feet during the day
    Checked 2026-10-11.

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FlyingAt cabin pressure altitudes above 12,500 and up to 14,000 feet, crew must use oxygen after how much time?FlyingAbove 15,000 feet MSL cabin pressure altitude, who must be provided with supplemental oxygen?FlyingAbove what cabin pressure altitude must supplemental oxygen be provided to every occupant of the aircraft?

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