Fault Detection in Aircraft Wiring using Enhanced multi-pulse TDR Technique

Defects in electrical wiring could result in disastrous consequences especially in airborne systems. The defects may in many cases be due to minor damage in the insulation or shielding of wires and cables. This type of defect is not usually detected using routine testing. They may be caused by vibration, moisture, heat, cold, abrasion and other similar effects, causing frays and cracking in wire insulation. Degradation and failure of aircraft wiring insulation is of particular interest which could lead to smoke and fire due to arcing. Results of a technique based on TDR, using trains of successive pulses was previously presented and confirmed through modelling of cables. In this paper the investigation is extended to include small 10 mm and 5 mm holes in coaxial and shielded twisted pair cables. The technique is easy to establish and due to its cumulative nature, can provide higher accuracy with increasing incremental steps. It also holds promise for detection of stray fields for non-contact detection of faults, particularly in shielded cables and wires.