Such a sudden release of pressure isn't only a hazard for divers, but also can be a danger in unpressurized civilian aircraft and high-flying military planes. Our bodies are saturated with nitrogen all the time, no matter the altitude at which we live. If an unpressurized airplane (usually a small, privately owned plane) rises quickly to altitudes of more than about 18,000 feet (5,500 meters) above sea level, that dissolved nitrogen can form bubbles, and the pilot and passengers suddenly find themselves dealing with the bends, even though they may be breathing oxygen to compensate for the thinner atmosphere. The solution is, of course, to come down to a lower altitude. Altitude-induced decompression sickness can also threaten military personnel who sometimes must work in depressurized sections of aircraft for a while, such as when a cargo door is opened for parachutists or an airdrop. In these instances, personnel who will be working in the unpressurized area breathe pure oxygen for a carefully regulated time period before the plane rises above a dangerous altitude, just as the aquanauts in Aquarius spent three 20-minute periods breathing oxygen at the beginning of their decompression. In each case, whether the person is high above the Earth or beneath the ocean's surface, the oxygen forces some of the dissolved nitrogen out of the body and reduces the chance of getting decompression sickness.
—Patricia Kellogg
