Novel detection technology for faulty aircraft wiring
Faulty wires can lead to the loss of vital controls or communications and fire. An international aviation incidents study found defective wiring to be the leading cause of 400 accidents during the period 1972-2000. Inspecting wires during routine maintenance remains a challenge because they are bundled into complex harnesses and often hidden behind structural components such as bulkheads. To address the limitations of traditional inspection methods, the EU-funded SAFEWIRE (Long range ultrasonic inspection of aircraft wiring) project sought to exploit and adapt long-range ultrasonic testing methods in order to deliver a cost- and time-efficient portable inspection system. Overall, the aim was to remotely detect critical insulation defects that are not easily seen or accessed by operators. In the SAFEWIRE concept, the wires themselves serve as wave guides. Sensor arrays are fastened to the harness and transmit ultrasound in a bundle of wires powered by a handheld pulser-receiver. The ultrasound picks up flaws in wiring up to a range of 10 m and transmits to the sensor assembly. Damage to insulation is identified by cutting-edge signal processing and pattern recognition techniques. Project stakeholders and end users were consulted on the technical, hardware and software requirements of the system. The common causes of aircraft wiring defects and existing conventional wire inspection methods were mapped. Guided waves in single wires were modelled and tests carried out on cables. The main system components were developed and tested, namely the ultrasonic transducer arrays, the handheld pulser-receiver and signal processing algorithms. The overall system was successfully demonstrated and validated in laboratory and field trials. SAFEWIRE introduced a safe and non-invasive inspection method that detects insulation defects while saving costs and time. Identifying issues with complex aircraft wiring before it is too late will enhance aviation safety for years to come.
Aircraft wiring, wiring inspection, aviation, ultrasonic inspection, insulation defects