Cabin altitude starts at the take off altitude.

客趁高度开始于起飞高度。

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The altitude inside the airplane (cabin altitude) also climbs but at a lower rate than the airplane.

飞机内部高度(坐舱高度)也以一个低于飞机的速率爬升。

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Cabin ALTITUDE, Atmospheric pressure maintained within the cabin, indicated in terms of feet above sea level.

座舱高度，座舱内保持的空气压力，以海拔多少英尺表示。

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To combat this threat, aircraft have a warning system which alerts the crew if the cabin altitude is approaching dangerous levels.

BBC: NEWS | Europe | Dangers of aircraft decompression

The reason is simple: the typical business jet or airliner cruising at 45, 000 feet will have a cabin altitude of about 8, 000 feet.

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Although jets are pressurized so that the cabin environment resembles an altitude of around 8, 000 feet, some people report that flying (possibly from the changes in pressure and resulting decrease in oxygen concentration) causes symptoms such as headache, fatigue and nausea.

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