The double cantilever beam has been widely used in the past and has proved one of the most popular designs for measuring the growth rate of stress corrosion cracks in materials. In this study, the double cantilever beam specimens were used to study the effect of tensile loading on stress corrosion cracking behaviour in aluminium alloy 7075(W). Cracks initiated readily in 3.5%NaCl solution with tensile loading conditions. Stress Corrosion Cracking (SCC) development was found to follow an intergranular path, which strongly depended on microstructure of material. Tests also were carried out to measure the threshold stress intensity, KISCC, which SCC would not occur. The SCC test was explained by an active path mechanism due to the galvanic interaction between grain boundary precipitates and adjacent precipitate-free zones. Crack lengths were measured with an eddy current bore probe and confirmed by optical metallography. The data from the eddy current tests on real stress corrosion cracks were used to construct an eddy current calibration curve for predicting stress corrosion crack lengths of aluminium alloy 7075(W).