失控减压，失压是指在密闭系统中气压无预期的降低，像是飞机客舱，并且通常是因为人为错误、金属疲劳、工程缺陷或是撞击，导致压力容器泄压至比其低压的周遭环境或无法使低压环境一同完全等压平衡。

如此的减压可分类为爆炸性，快速或是慢速:

Uncontrolled decompression is an unplanned drop in the pressure of a sealed system, such as an aircraft cabin, and typically results from human error, material fatigue, engineering failure, or impact, causing a pressure vessel to vent into its lower-pressure surroundings or fail to pressurize at all.