Life support system

Referring first to FIG. 1 there is shown a typical flight profile of an aircraft in the event of an emergency decompression.

In this example, an aircraft flying at 40,000 feet (line A), when experiencing an emergency such as cabin decompression at B, which result in increased demand for oxygen or oxygen enriched gas, would rapidly descend to a low altitude C of 10,000 feet or less. During this descent, an emergency supply of oxygen would be provided to crew and passengers of the aircraft, from compressed oxygen storage containers, or as a result of a chemical reaction between two or more reagents. At 10,000 feet C, the passengers at least can safely breath atmospheric air. The aircraft continues to fly at this low altitude until it is safe to descent to land D, or until the pilot decides it is safer to ditch the aircraft in the sea.

It will be appreciated that terrain T in many land masses extends above 10,000 feet and thus conventionally there is a risk that during low altitude flight s