Chapter 9 Engine Fire  Protection Systems Introduction Because fire is one of the most dangerous threats to an  aircraft, the potential fire zones of all multiengine aircraft  currently produced are protected by a fixed fire protection  system. A “fire zone” is an area or region of an aircraft  designated by the manufacturer to require fire detection  and/or fire extinguishing equipment and a high degree  of inherent fire resistance. The term “fixed” describes a  permanently installed system in contrast to any type of  portable fire extinguishing equipment, such as a hand-held  fire extinguisher. 