Technology update II: Wire systems diagnostics & prognostics

The Aviation industry is gradually realizing some of the benefits from wire husbandry as they include it in their maintenance programs. Individual operators are also beginning to incorporate both zonal visual inspection procedures and advanced diagnostic tooling practices into their maintenance programs. Visual inspection, although only 25% effective is being used to check for wire contamination, combustibles and wire degradation from adverse human actions and operational environment. VSWReflectometry (VSWR) in conjunction with automatic test equipment (ATE) is 95% effective in finding, defining and locating wire system faults. Although this represents a quantum step forward in conducting maintenance on a per aircraft basis true value will not be realized until the full complement of software support programs are placed into service. To truly realize the benefit of advanced test equipment a database of fleet wide information must be established and used for future diagnostic, prognostic, verification and related purposes. Analytical software programs must be developed which brings prognostics as a decision-maker into the wire husbandry program based on fleet information. The obvious software programs such as useful remaining life, trend analysis and performance standards will at first be based on fleet averages of individual systems performance. Further programs will be developed based on individual needs of the particular operator. Both A.C. and D.C. software driven test patterns are used to define wire systems degradation with the sensed data available for downloading and processing. Single ended testing using VSWReflectometry is generally used on balanced circuits and can define fault, fault location and failed components at this time. It is usually used when a single system is being tested at any of the 3 levels o