A fan type compressor includes a rotor disk with a plurality of root insertion openings to receive a blade. Each insertion opening includes two shear pin slots on the sides, and the blade includes a root portion with shear pin slots formed on the pressure side and the suction side of the root. The blade is inserted into the insertion opening such that the slots are aligned, and a shear pin is inserted into both slots to secure the blade within the rotor disk. The shear pin slots are formed below the airfoil curvature and follow the airfoil curvature at the root portion. The shear pins are flexible enough to bend during insertion into the slots, and are strong enough to prevent from shearing off during rotor disk operation. The blade attachment structure provides for reduction of the dead weight from the attachment structure in order to simulate an IBR while providing for easy removal and replacement of a damaged blade.