SAFEWIRE · Long Range Ultrasonic Inspection of Aircraft Wiring

Defects in the electric wiring in aircraft have led to serious accidents. Cases in point were the losses of TWA Flight 800 in July 1996 and Swissair Flight 111 September 1998, in both of which ~ 230 people died. Experts investigating almost three decades of international aviation incidents between 1972 and 2000 found more than 400 wire related incidents. The Ageing Transport Systems Rulemaking Advisory Committee (ATSRAC) found 2281 individual discrepancies in 39 aircraft, 73 of which were deemed significant, 31% of these being concerned with wiring. It can be concluded that one in two of the aircraft studied had a serious wiring fault.Aircraft wiring is bundled in looms or harnesses and these are often concealed by bulkheads, making them very difficult to inspect. There is, therefore, a need to develop a non-destructive testing method enabling the remote inspection of wiring looms that are inaccessible for inspection by current methods.This project proposes to develop a novel wiring inspection technique based on the use of long range ultrasonic testing techniques in which the wires themselves act as wave guides. A sensor or sensor array will be clamped to the harness. This will be energised by a handheld pulser/receiver. Flaws in the wiring will reflect ultrasound back to the sensor assembly and will be detected by the pulser/receiver. Insulation damage will be recognised by advanced signal processing and pattern recognition techniques.