At cruising altitude of 37,000 ft, the cabin pressure is maintained at what altitude range?

• A. 3,000-4,000 ft
• B. 6,000-8,000 ft
• C. 10,000-12,000 ft
• D. 20,000-22,000 ft

Answer: (B)

When the aircraft climbs to cruising height, the outside air is too thin for safe, comfortable breathing, so the cabin is pressurized to simulate a lower altitude. In most jet aircraft, that cabin altitude is about six to eight thousand feet. This keeps the oxygen level adequate and reduces fatigue, while staying within the aircraft’s structural limits for the pressure difference across the fuselage. A cabin altitude around three to four thousand feet would demand a higher pressure differential and strain the hull, while much higher altitudes (ten to twelve thousand or twenty thousand feet) would make breathing noticeably harder and could lead to hypoxia.