At the pictures above and to the right you see the rotor of the centrifugal low pressure stage of the fuel pump or boost stage. Note the helicoid part at the center of the rotor which helps the pump to have more effective suction in case the boost pump at the fuel tanks are inoperative for some reason. Engine driven fuel pump must be able to deliver normal working pressure even with the electric fuel boost pumps, (placed in the wing fuel tanks), not working.
At the picture to the right you can see in a better way the helicoid channels of the rotor. The channels are machined on both sides of the rotor. The material of the rotor is light aluminum alloy.