Rapid depressurisation refers to a quick drop in cabin pressure that happens faster than the lungs can adjust, yet not so fast that it causes lung damage. This event is more frequent than explosive depressurisation and typically occurs in larger aircraft. It can happen in seconds, often at a rate exceeding 7,000 feet per minute, usually accompanied by a loud noise and a sudden fogging of the cabin air.
The primary risk during depressurisation is crew incapacitation due to hypoxia, which is a lack of oxygen. The time of useful consciousness decreases as the speed of decompression increases, making it critical for crew and passengers to be prepared. Another potential danger is decompression sickness, which can occur after high-altitude depressurisation.
If the depressurisation results from structural failure, such as a broken window, there are additional hazards. Crew and passengers may face strong winds, flying debris, extreme cold, or even the risk of being sucked out of the aircraft. This highlights the importance of wearing seat belts or harnesses whenever seated.
