Acoustic System for Online Wiring Test on Aircraft

Wiring onboard of legacy aircraft is becoming a liability due to a prolonged use of aircraft. Testing as well as repairs and maintenance require extensive number of man-hours bringing up the costs and reducing flight time of the aircraft. There is a number of conventional electric testing methods for wire testing, yet we propose and evaluate an acoustic (mechanical) testing method. Acoustic testing can be used online while the wire is in operation, and has the capability for intermittent fault detection. We report modelling and experimental results of an insulated wire that indicate this technique can be used to detect mechanical faults in insulation and conducting wire core. We used two different methods to detect and locate insulation defects of only 0.2mm wide. Transmission mode allowed a clear detection of the defect while reflection mode yielded the defect position.