Epicyclic gear system having two arrays of pinions mounted on flexpins with compensation for carrier distortion

An epicyclic gear system includes sun and ring gears (2, 4), planet pinions (6, 8) arrayed (a, b) between these gears, and a carrier (10) to which planet pinions are coupled through flexpins (30). The pinions are located between carrier walls (20, 22) with flexpins for the respective arrays cantilevered from opposite walls. The carrier is subjected to externally applied torque which transfers through the system. The load path (pa) for one array is shorter than that (pb) for the other array, which disparity causes carrier distortion with flexpins on one wall angularly displaced from flexpins on the other wall. The system compensates for this by one wall having areas (40, 44) of weakness where the flexpins cantilever from it. This enables the pinions of the two arrays to better mesh under a load and share torque transfer more evenly.