Abstract: The present invention relates to a test blade for a blade-release test. The blade is arranged in use to be mounted on a hub for rotation, and to be released therefrom by the action of a controlled explosion. The blade is arranged to receive at least one explosive charge and at least one detonator for detonating the charge. The blade further comprises a cut-through portion extending completely through the blade from a front face to a rear face, the cut-through portion also extending part way along the blade in an axial direction between a leading edge and a trailing edge of the blade.