Analysis of reflectometry for detection of chafed aircraft wiring insulation

Aircraft around the world today are flying more and more hours and are being flown for more years before retirement than ever before. The rigorous schedules and environment that most aircraft find themselves in may lead to certain maintenance problems. One of these problems is the degradation of the insulation on the electrical wires over the life of the aircraft. These problems can vary from large sections of cable insulation being rubbed away to microscopic cracks found in the insulation.; If these frays in the insulation are found early, they can be repaired and serious problems with the aircraft can be avoided. A system has been developed at Utah State University that detects when an open or short circuit has occurred in a wire, and this research presents the initial work in developing a system that is able to detect frays before they become open or short circuits. The technique employed is to use time domain reflectometry to obtain data on a variety of frays in the time domain. The time domain data are then processed through a Fourier transform and converted to the frequency domain. The frequency domain data are then analyzed to determine the frequency dependency of fray detection. Frequencies that are viable for use for fray detection were found and future work recommendations for the adaptation of the existing Utah State University system were made.