ABSTRACT
All cabin depressurisation needs immediate assessment and active management. Rate of cabin decompression is governed by pressure factor and dimensional factor. Absolute differential pressure will determine severity of decompression with respect to gas expansion, worse with greater pressure difference. Absolute barometric pressure following decompression will determine physiological consequences. During rapid decompression, pressure falls quickly at first and then more slowly as pressures equilibrate. Major factors influencing rate and time of decompression are: cabin volume, orifice size , cabin absolute pressure at start of depressurisation and ambient absolute pressure external to cabin. Rate of decompression can be predicted by: Fliegner’s equation. Passengers receive emergency oxygen from drop-down masks; the duration of supply is limited but is intended to maintain consciousness during emergency descent to safe transit altitude. Military fast jet aircraft is equipped with life support systems that should automatically deliver emergency 100% oxygen in event of cabin decompression.
