Non-destructive fault location on aging aircraft wiring networks, Part 2- live wires in flight

Aging aircraft wiring has been identified as an area of critical national concern. As the system ages, the wires become brittle and crack, break, or develop short circuits. Short circuits, in particular, have been implicated in a variety of smoke incidents, in-flight fires, and crashes. Some of these faults are intermittent, occurring only sporadically as the physical vibration, stresses, temperatures, electrical loads, moisture condensation, etc. change throughout the flight. When the plane is on the ground, no fault can be found. These types of problems are among the most frustrating for aircraft maintainers, resulting in a typical "no fault found" incident taking tens or even hundreds of hours to locate. Some planes even remain grounded for extended periods of time until basic electrical systems can be fully replaced at great cost and labor. One of the greatest hazards of these systems is that they may foreshadow a more serious in flight hazard as a small fault grows, yet for all intents and purposes, the system checks out OK.