Technology update I: Wiring prognostic tools

Abstract

Current wire system inspection processes do not compliment aircraft electrical and electronic systems technology nor do many proposed or existing systems. The volt/ohm meter, the meg/ohm meter, and visual techniques can represent the wire inspection tools in common use today. These two meters only measure conductivity, connectivity, and voltage breakdown strength of the insulation. Visual techniques (mirror and flashlight methods) can only reach about 25 percent of the aircraft wiring system and subjectively identify only physical faults of the insulation surface and simple damaged components. Little can be determined relative to the wire performance, wire insulation, wire bundle, connector, connector pins & backshell, wire supports, grounding, shielding or intended electrical systems performance as a transmission line and part of the larger avionics system of the aircraft. These require data to analyze and manage the health of the wire system. Enhanced zonal analysis procedures (EZAP) are just now becoming available to the electrical repairman for performing simplified zonal inspections to identify obvious wiring faults and the presence of combustible materials. This is done at a predetermined level and interval of inspection and is a portion of the Wire Husbandry Program. It is a preventive measure against fire and an improvement over existing methods. Visual zonal inspection is only 25 percent effective in determining wire system degradation and locating wire faults. Important details for locating physical faults and poor performance of the electrical system are missing. Some of the larger questions such as wire useful life, projected repair schedules for the C & D checks based on delayed maintenance, etc., best tools and repair processes, consumables, etc. are missing. These limitations are being overcome