Military digital avionics fiber-optic network design for maintainability and supportability

The Boeing 777 PlaneNet program provides a textbook example of "how to" build and deploy a fiber optic based avionics local area network on commercial aircraft (Anderson and Beranek, 1998). Tactical aircraft, however, does not yet have a time-tested process to draw upon for operational readiness lessons learned, particularly in the area of aircraft squadron fiber optic network maintainability and supportability. The tactical aircraft fiber optic network design team must consider both the harsh avionics operational environment and the harsh avionics maintenance environment - as many fiber optic components from the commercial sector are not adequate for the tactical aircraft mission environment; and many fiber optic maintenance support equipment options available from the commercial sector are not adequate for use on an aircraft carrier or expeditionary airfield. In this paper we attempt to define items necessary to ensure military avionics fiber optic network design interfaces are deployed in a maintainable and supportable manner. The term maintainability defines how quickly, easily, and cost effectively an avionics fiber optic network design facilitates its\´ return to operational status (whether by preventive or corrective maintenance). Mean Time To Repair (MTTR) is used to quantify and measure maintainability. Supportability, on the other hand, is the degree to which the avionics fiber optic network design characteristics minimize the logistics resources (people, skill levels, parts, publications, tools, test equipment, space, etc.) required to sustain the system\´s Operational Availability (A₀) at an affordable cost throughout the intended life of the system.