Single instrument combines eddy-current and ultrasonic testing for fuselage NDT

A new inspection platform puts eddy-current and ultrasonic testing in one instrument for fuselage non-destructive testing, the manufacturer says.

According to the company, scratches on aluminium alloy airframes are normally removed by mechanical blend-out during manufacturing and scheduled maintenance. Fuselage skin panels have a cladding layer of pure 1000-series aluminium over a 2024 alloy substrate. The cladding is only 2% to 4% of the sheet and runs between 0.04 mm and 0.40 mm deep.

Blend-out that cuts through the cladding exposes the stronger core alloy to corrosion, the announcement says. The removal site cannot be seen with the naked eye, so inspection is needed to confirm missing clad and measure remaining wall thickness.

The two materials differ in electrical conductivity. At about 1 MHz, cladded 2024 plates measure 26 to 36 MS/m depending on thickness, while uncladded sections drop to 17 to 18 MS/m, according to the company. That gap is the basis for using eddy-current testing to locate the cladding boundary. High-frequency ultrasonics separately gauges remaining wall thickness inside the blended cavity.

Running both methods has traditionally taken separate instruments, which the manufacturer says adds complexity and splits the data. The Smart UE1 EVO platform addresses this by driving a 2 MHz probe and combining the two measurements in one unit.