A gearbox includes a sun gear, a plurality of planet gears, an annulus gear and a planet carrier. The planet carrier includes a first ring, second ring spaced axially from the first ring, a plurality of circumferentially spaced axles and a plurality of circumferentially spaced support structures extending axially between and secured to the first ring and second ring. Each planet gear is rotatably mounted on a respective one of the axles. The first ring has a plurality of circumferentially spaced recesses and the second ring has a plurality of circumferentially spaced recesses. Each recess in the second ring is aligned with a corresponding one of the recesses in the first ring. A first end of each support structure locates in a recess in the first ring. A second end of each support structure locates in a recess in the second ring. Each support structure comprises a fused powdered material.