Which cabin altitude range is maintained during cruise?

• A. 3,000-5,000 ft
• B. 6,000-8,000 ft
• C. 9,000-11,000 ft
• D. 12,000-14,000 ft

Answer: (B)

Cabin altitude kept during cruise is the effective indoor height the passengers experience, not the airplane’s actual height above the ground. Airlines set this to a comfortable level that also aligns with the aircraft’s design limits. In practice, the cabin is held at about 6,000–8,000 feet. This range provides enough oxygen to keep passengers comfortable and reduce fatigue, while the pressurization system only needs to maintain a moderate pressure difference between inside and outside.

Choosing this range is a balancing act. If the cabin were kept much lower than 6,000 feet, the aircraft would need to sustain a higher pressure difference, which increases structural load, weight, and cost. If it were kept higher than 8,000 feet, passengers might feel the effects of reduced oxygen more quickly, especially on longer flights. So 6,000–8,000 feet is the practical compromise that most commercial jets use during cruise.