This paper discusses the Douglas DC-9 Fire Detector System and the considerations involved in making the selection. Areas of interest that are covered include: the importance of reliable fire detection to commercial airplane operators, a reliability approach to system selection, primary reasons for selection of the particular DC-9 system, the operation of the DC-9 equipment, and the design concepts considered in the installation of the system in the airplane to reduce component failure.
A discussion of improvements in the system over current installations with respect to its ability to discriminate between a fire and a system malfunction of any kind will be presented.