explosive decompression

This technical phrase is frequently heard on Star Trek when a starship is getting hit hard in battle. Theoretically, in Sci-Fi, explosive decompression is where the parts of the hull of the ship are exploding into space rapidly, and air is quickly venting from that section. In the real world explosive decompression is simply rapid decompression. This is very different than slow decompression, which would be a small leak affecting the air pressure and eventually starving the spacefarers of oxygen. Slow decompression occurred onboard Mir now and then.

Geoffrey A. Landis has written an excellent paper describing the effects of explosive decompression and vacuum exposure at http://www.sff.net/people/Geoffrey.Landis/vacuum.html

If at some point you are about to experience rapid decompression, do not try to hold your breath! Your lungs will explode. People exposed to sorts of explosive decompression may develop a painful and often fatal disease known as The Bends.

Planes and explosive decompression

It is a common movie effect for everything on a plane to be blown out the side if a bullet is fired through the outer structure (window, hull, etc.). This is not what would happen.

A single bullet will not crash your next flight to Florida or wherever. If a whole window is blown out, then there will be a more rapid decompression but you and everything around will not necessarily (but possibly may) be ripped forcefully from the status quo. It would require atleast three windows, or the door, which is vacuum sealed and is almost a foot thick Therefore unlikely...VERY unlikely, to be blown off in order to cause an explosive decompression. Only a hole this big would allow enough of the pressurized air inside the plane out fast enough to cause the severe chaos and destruction depicted in the movies.

This is not to say explosive decompression is next to impossible. There are documented cases of planes undergoing an explosive decompression due to structure weakness and other similar causes. But even these did not result in a dramatic loss of life.

A few examples of explosive decompression

• 11/3/1973 National Airlines DC10-10 Albuquerque, New Mexico
  Overspeeding of the starboard engine caused the engine to disintegrate. Pieces struck the fuselage, breaking a window, causing rapid explosive decompression and a passenger was sucked out of the plane. The plane landed safely. Out of boredom, the captain and flight engineer decided to experiment and see what would happen to the autothrottle system if the circuit breakers which supplied power to the instruments which measured the rotational speed of each engine's low pressure compressor were tripped. This led to engine overspeeding and destruction of the engine.


• 02/24/1989 United Air Lines B-747-122 Honolulu, Hawaii
  After leaving Honolulu, on a flight from Los Angeles to Sydney, Australia, the improperly locked foward lower lobe cargo door suddenly opened resulting in explosive decompression and loss of power in the No. 3 and 4 engines. Nine passengers were sucked out of the plane and lost at sea but the plane landed safely.


• 06/10/1990 British Airways BAC-111 Oxfordshire, England
  On a flight from Birmingham, England to Malaga, Spain, at FL 173, a large section of windshield fell away from the aircraft. The decompression pulled the captain out from under his seatbelt. Despite trying to hold onto the yoke, the captain was sucked out into the opening. A steward in the cockpit was able to grab hold of his legs. Another steward was able to strap himself into the vacant seat and aid in holding onto the captain's legs. The copilot, wearing full restraints, made an emergency landing at Southampton. The captain remained half way out of the aircraft for 15 minutes and suffered only frostbite and some fractures. Improper bolts used to replace the windshield two days earlier resulted in the accident.


• Source: http://www.planecrashinfo.com/unusual.htm

More details available at http://www.gadgetopia.com/2004/07/07/TheTruthAboutExplosiveDecompression.html