A test blade for use in a blade-release test in which the blade is mounted on a rotatable hub and at least a portion of the blade is released therefrom by the action of a controlled explosion. The blade has a root portion for mounting on said rotatable hub and the root portion comprises a radially inner surface having a channel extending at least partly along or proximal the camber line. The channel is for receiving at least one explosive charge and at least one detonator which may be contained within a charge carrier.

Anti-rotation tabs for the platforms in the fan section of a gas turbine engine are provided. The anti-rotation tabs interface with the trailing edge of the spinner, thereby preventing the platform from rotating and twisting.

A rotor disc (1) for a turbomachine, including a radial flange (2) that includes a plurality of fastening holes (3), and a plurality of scallops (4) forming notches in the flange (2), and being separated by inter-scallop flange portions (7). The flange alternatively has, in its circumferential direction: a fastening hole (3) and an inter-scallop flange portion (7) arranged in the radial extension of the fastening hole (3), and a scallop (4), in such a way that one or more of the scallops (4.sub.7, 4.sub.8, 4.sub.9; 4.sub.2, 4.sub.5-4.sub.7, 4.sub.8-4.sub.11, 4.sub.14) has a volume greater than the volume of each of the other scallops (4.sub.1-4.sub.6, 4.sub.10-4.sub.14; 4.sub.1, 4.sub.3, 4.sub.4, 4.sub.12, 4.sub.13), and one or more of the inter-scallop flange portions (7.sub.3) has a volume less than the volume of each of the other inter-scallop flange portions (7.sub.1, 7.sub.2, 7.sub.4), in order to balance said disc (1). A turbomachine including that rotor disc and a method for balancing a turbomachine rotor disc are also disclosed.